Generate -errorcode values to go with errors. Generate messages and postscript

using Tcl_Obj API, not the string result API.

79 files changed, 3880 insertions, 2941 deletions

diff --git a/generic/tk3d.c b/generic/tk3d.c
index 2920c76..dd7ab2f 100644
--- a/generic/tk3d.c
+++ b/generic/tk3d.c
@@ -673,11 +673,10 @@ Tk_GetRelief(
     } else if ((c == 's') && (strncmp(name, "sunken", length) == 0)) {
 	*reliefPtr = TK_RELIEF_SUNKEN;
     } else {
-	char buf[200];
-
-	sprintf(buf, "bad relief \"%.50s\": must be %s",
-		name, "flat, groove, raised, ridge, solid, or sunken");
-	Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	Tcl_SetObjResult(interp,
+		Tcl_ObjPrintf("bad relief \"%.50s\": must be %s",
+		name, "flat, groove, raised, ridge, solid, or sunken"));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "RELIEF", NULL);
 	return TCL_ERROR;
     }
     return TCL_OK;
diff --git a/generic/tkArgv.c b/generic/tkArgv.c
index 3f235ad..6c2c5c5 100644
--- a/generic/tkArgv.c
+++ b/generic/tkArgv.c
@@ -70,7 +70,7 @@ Tk_ParseArgv(
     register const Tk_ArgvInfo *infoPtr;
 				/* Pointer to the current entry in the table
 				 * of argument descriptions. */
-    const Tk_ArgvInfo *matchPtr;	/* Descriptor that matches current argument. */
+    const Tk_ArgvInfo *matchPtr;/* Descriptor that matches current argument. */
     const char *curArg;		/* Current argument */
     register char c;		/* Second character of current arg (used for
 				 * quick check for matching; use 2nd char.
@@ -83,6 +83,7 @@ Tk_ParseArgv(
 				 * than srcIndex). */
     int argc;			/* # arguments in argv still to process. */
     size_t length;		/* Number of characters in current argument. */
+    char *endPtr;		/* Used for identifying junk in arguments. */
     int i;
 
     if (flags & TK_ARGV_DONT_SKIP_FIRST_ARG) {
@@ -139,8 +140,10 @@ Tk_ParseArgv(
 		    continue;
 		}
 		if (matchPtr != NULL) {
-		    Tcl_AppendResult(interp, "ambiguous option \"", curArg,
-			    "\"", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "ambiguous option \"%s\"", curArg));
+		    Tcl_SetErrorCode(interp, "TK", "ARG", "AMBIGUOUS", curArg,
+			    NULL);
 		    return TCL_ERROR;
 		}
 		matchPtr = infoPtr;
@@ -153,8 +156,10 @@ Tk_ParseArgv(
 	     */
 
 	    if (flags & TK_ARGV_NO_LEFTOVERS) {
-		Tcl_AppendResult(interp, "unrecognized argument \"",
-			curArg, "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"unrecognized argument \"%s\"", curArg));
+		Tcl_SetErrorCode(interp, "TK", "ARG", "UNRECOGNIZED", curArg,
+			NULL);
 		return TCL_ERROR;
 	    }
 	    argv[dstIndex] = curArg;
@@ -175,25 +180,23 @@ Tk_ParseArgv(
 	case TK_ARGV_INT:
 	    if (argc == 0) {
 		goto missingArg;
-	    } else {
-		char *endPtr;
-
-		*((int *) infoPtr->dst) = strtol(argv[srcIndex], &endPtr, 0);
-		if ((endPtr == argv[srcIndex]) || (*endPtr != 0)) {
-		    Tcl_AppendResult(interp,"expected integer argument for \"",
-			    infoPtr->key, "\" but got \"", argv[srcIndex],
-			    "\"", NULL);
-		    return TCL_ERROR;
-		}
-		srcIndex++;
-		argc--;
 	    }
+	    *((int *) infoPtr->dst) = strtol(argv[srcIndex], &endPtr, 0);
+	    if ((endPtr == argv[srcIndex]) || (*endPtr != 0)) {
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"expected %s argument for \"%s\" but got \"%s\"",
+			"integer", infoPtr->key, argv[srcIndex]));
+		Tcl_SetErrorCode(interp, "TK", "ARG", "INTEGER", curArg,NULL);
+		return TCL_ERROR;
+	    }
+	    srcIndex++;
+	    argc--;
 	    break;
 	case TK_ARGV_STRING:
 	    if (argc == 0) {
 		goto missingArg;
 	    }
-	    *((const char **)infoPtr->dst) = argv[srcIndex];
+	    *((const char **) infoPtr->dst) = argv[srcIndex];
 	    srcIndex++;
 	    argc--;
 	    break;
@@ -201,7 +204,7 @@ Tk_ParseArgv(
 	    if (argc == 0) {
 		goto missingArg;
 	    }
-	    *((Tk_Uid *)infoPtr->dst) = Tk_GetUid(argv[srcIndex]);
+	    *((Tk_Uid *) infoPtr->dst) = Tk_GetUid(argv[srcIndex]);
 	    srcIndex++;
 	    argc--;
 	    break;
@@ -211,19 +214,17 @@ Tk_ParseArgv(
 	case TK_ARGV_FLOAT:
 	    if (argc == 0) {
 		goto missingArg;
-	    } else {
-		char *endPtr;
-
-		*((double *) infoPtr->dst) = strtod(argv[srcIndex], &endPtr);
-		if ((endPtr == argv[srcIndex]) || (*endPtr != 0)) {
-		    Tcl_AppendResult(interp, "expected floating-point ",
-			    "argument for \"", infoPtr->key, "\" but got \"",
-			    argv[srcIndex], "\"", NULL);
-		    return TCL_ERROR;
-		}
-		srcIndex++;
-		argc--;
 	    }
+	    *((double *) infoPtr->dst) = strtod(argv[srcIndex], &endPtr);
+	    if ((endPtr == argv[srcIndex]) || (*endPtr != 0)) {
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"expected %s argument for \"%s\" but got \"%s\"",
+			"floating-point", infoPtr->key, argv[srcIndex]));
+		Tcl_SetErrorCode(interp, "TK", "ARG", "FLOAT", curArg, NULL);
+		return TCL_ERROR;
+	    }
+	    srcIndex++;
+	    argc--;
 	    break;
 	case TK_ARGV_FUNC: {
 	    typedef int (ArgvFunc)(char *, const char *, const char *);
@@ -249,6 +250,7 @@ Tk_ParseArgv(
 	}
 	case TK_ARGV_HELP:
 	    PrintUsage(interp, argTable, flags);
+	    Tcl_SetErrorCode(interp, "TK", "ARG", "HELP", NULL);
 	    return TCL_ERROR;
 	case TK_ARGV_CONST_OPTION:
 	    Tk_AddOption(tkwin, infoPtr->dst, infoPtr->src,
@@ -265,8 +267,11 @@ Tk_ParseArgv(
 	    break;
 	case TK_ARGV_OPTION_NAME_VALUE:
 	    if (argc < 2) {
-		Tcl_AppendResult(interp, "\"", curArg,
-			"\" option requires two following arguments", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"\"%s\" option requires two following arguments",
+			curArg));
+		Tcl_SetErrorCode(interp, "TK", "ARG", "NAME_VALUE", curArg,
+			NULL);
 		return TCL_ERROR;
 	    }
 	    Tk_AddOption(tkwin, argv[srcIndex], argv[srcIndex+1],
@@ -274,14 +279,12 @@ Tk_ParseArgv(
 	    srcIndex += 2;
 	    argc -= 2;
 	    break;
-	default: {
-	    char buf[64 + TCL_INTEGER_SPACE];
-
-	    sprintf(buf, "bad argument type %d in Tk_ArgvInfo", infoPtr->type);
-	    Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	default:
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad argument type %d in Tk_ArgvInfo", infoPtr->type));
+	    Tcl_SetErrorCode(interp, "TK", "API_ABUSE", NULL);
 	    return TCL_ERROR;
 	}
-	}
     }
 
     /*
@@ -301,8 +304,9 @@ Tk_ParseArgv(
     return TCL_OK;
 
   missingArg:
-    Tcl_AppendResult(interp, "\"", curArg,
-	    "\" option requires an additional argument", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "\"%s\" option requires an additional argument", curArg));
+    Tcl_SetErrorCode(interp, "TK", "ARG", "MISSING", curArg, NULL);
     return TCL_ERROR;
 }
 
@@ -328,7 +332,7 @@ static void
 PrintUsage(
     Tcl_Interp *interp,		/* Place information in this interp's result
 				 * area. */
-    const Tk_ArgvInfo *argTable,	/* Array of command-specific argument
+    const Tk_ArgvInfo *argTable,/* Array of command-specific argument
 				 * descriptions. */
     int flags)			/* If the TK_ARGV_NO_DEFAULTS bit is set in
 				 * this word, then don't generate information
@@ -336,7 +340,7 @@ PrintUsage(
 {
     register const Tk_ArgvInfo *infoPtr;
     size_t width, i, numSpaces;
-    char tmp[TCL_DOUBLE_SPACE];
+    Tcl_Obj *message;
 
     /*
      * First, compute the width of the widest option key, so that we can make
@@ -348,6 +352,7 @@ PrintUsage(
 	for (infoPtr = i ? defaultTable : argTable;
 		infoPtr->type != TK_ARGV_END; infoPtr++) {
 	    size_t length;
+
 	    if (infoPtr->key == NULL) {
 		continue;
 	    }
@@ -358,35 +363,35 @@ PrintUsage(
 	}
     }
 
-    Tcl_AppendResult(interp, "Command-specific options:", NULL);
+    message = Tcl_NewStringObj("Command-specific options:", -1);
     for (i = 0; ; i++) {
 	for (infoPtr = i ? defaultTable : argTable;
 		infoPtr->type != TK_ARGV_END; infoPtr++) {
 	    if ((infoPtr->type == TK_ARGV_HELP) && (infoPtr->key == NULL)) {
-		Tcl_AppendResult(interp, "\n", infoPtr->help, NULL);
+		Tcl_AppendPrintfToObj(message, "\n%s", infoPtr->help);
 		continue;
 	    }
-	    Tcl_AppendResult(interp, "\n ", infoPtr->key, ":", NULL);
+	    Tcl_AppendPrintfToObj(message, "\n %s:", infoPtr->key);
 	    numSpaces = width + 1 - strlen(infoPtr->key);
 	    while (numSpaces-- > 0) {
-		Tcl_AppendResult(interp, " ", NULL);
+		Tcl_AppendToObj(message, " ", 1);
 	    }
-	    Tcl_AppendResult(interp, infoPtr->help, NULL);
+	    Tcl_AppendToObj(message, infoPtr->help, -1);
 	    switch (infoPtr->type) {
 	    case TK_ARGV_INT:
-		sprintf(tmp, "%d", *((int *) infoPtr->dst));
-		Tcl_AppendResult(interp, "\n\t\tDefault value: ", tmp, NULL);
+		Tcl_AppendPrintfToObj(message, "\n\t\tDefault value: %d",
+			*((int *) infoPtr->dst));
 		break;
 	    case TK_ARGV_FLOAT:
-		Tcl_PrintDouble(NULL, *((double *) infoPtr->dst), tmp);
-		Tcl_AppendResult(interp, "\n\t\tDefault value: ", tmp, NULL);
+		Tcl_AppendPrintfToObj(message, "\n\t\tDefault value: %f",
+			*((double *) infoPtr->dst));
 		break;
 	    case TK_ARGV_STRING: {
 		char *string = *((char **) infoPtr->dst);
 
 		if (string != NULL) {
-		    Tcl_AppendResult(interp, "\n\t\tDefault value: \"", string,
-			    "\"", NULL);
+		    Tcl_AppendPrintfToObj(message,
+			    "\n\t\tDefault value: \"%s\"", string);
 		}
 		break;
 	    }
@@ -398,8 +403,9 @@ PrintUsage(
 	if ((flags & TK_ARGV_NO_DEFAULTS) || (i > 0)) {
 	    break;
 	}
-	Tcl_AppendResult(interp, "\nGeneric options for all commands:", NULL);
+	Tcl_AppendToObj(message, "\nGeneric options for all commands:", -1);
     }
+    Tcl_SetObjResult(interp, message);
 }
 
 /*
diff --git a/generic/tkBind.c b/generic/tkBind.c
index e58ad4d..7126e24 100644
--- a/generic/tkBind.c
+++ b/generic/tkBind.c
@@ -620,7 +620,7 @@ static PatSeq *		FindSequence(Tcl_Interp *interp,
 static void		GetAllVirtualEvents(Tcl_Interp *interp,
 			    VirtualEventTable *vetPtr);
 static char *		GetField(char *p, char *copy, int size);
-static void		GetPatternString(PatSeq *psPtr, Tcl_DString *dsPtr);
+static Tcl_Obj *	GetPatternObj(PatSeq *psPtr);
 static int		GetVirtualEvent(Tcl_Interp *interp,
 			    VirtualEventTable *vetPtr, Tcl_Obj *virtName);
 static Tk_Uid		GetVirtualEventUid(Tcl_Interp *interp,
@@ -1094,13 +1094,14 @@ Tk_GetAllBindings(
 {
     PatSeq *psPtr;
     Tcl_HashEntry *hPtr;
-    Tcl_DString ds;
+    Tcl_Obj *resultObj;
 
     hPtr = Tcl_FindHashEntry(&bindPtr->objectTable, (char *) object);
     if (hPtr == NULL) {
 	return;
     }
-    Tcl_DStringInit(&ds);
+
+    resultObj = Tcl_NewObj();
     for (psPtr = Tcl_GetHashValue(hPtr); psPtr != NULL;
 	    psPtr = psPtr->nextObjPtr) {
 	/*
@@ -1108,11 +1109,9 @@ Tk_GetAllBindings(
 	 * its sequence.
 	 */
 
-	Tcl_DStringSetLength(&ds, 0);
-	GetPatternString(psPtr, &ds);
-	Tcl_AppendElement(interp, Tcl_DStringValue(&ds));
+	Tcl_ListObjAppendElement(NULL, resultObj, GetPatternObj(psPtr));
     }
-    Tcl_DStringFree(&ds);
+    Tcl_SetObjResult(interp, resultObj);
 }
 
 /*
@@ -1223,7 +1222,8 @@ Tk_BindEvent(
     PatSeq *vMatchDetailList, *vMatchNoDetailList;
     int flags, oldScreen;
     Tcl_Interp *interp;
-    Tcl_DString scripts, savedResult;
+    Tcl_DString scripts;
+    Tcl_InterpState interpState;
     Detail detail;
     char *p, *end;
     TkWindow *winPtr = (TkWindow *) tkwin;
@@ -1453,14 +1453,13 @@ Tk_BindEvent(
      */
 
     interp = bindPtr->interp;
-    Tcl_DStringInit(&savedResult);
 
     /*
      * Save information about the current screen, then invoke a script if the
      * screen has changed.
      */
 
-    Tcl_DStringGetResult(interp, &savedResult);
+    interpState = Tcl_SaveInterpState(interp, TCL_OK);
     screenPtr = &bindInfoPtr->screenInfo;
     oldDispPtr = screenPtr->curDispPtr;
     oldScreen = screenPtr->curScreenIndex;
@@ -1475,7 +1474,7 @@ Tk_BindEvent(
     end = p + Tcl_DStringLength(&scripts);
 
     /*
-     * Be carefule when dereferencing screenPtr or bindInfoPtr. If we evaluate
+     * Be careful when dereferencing screenPtr or bindInfoPtr. If we evaluate
      * something that destroys ".", bindInfoPtr would have been freed, but we
      * can tell that by first checking to see if winPtr->mainPtr == NULL.
      */
@@ -1523,7 +1522,7 @@ Tk_BindEvent(
 	screenPtr->curScreenIndex = oldScreen;
 	ChangeScreen(interp, oldDispPtr->name, oldScreen);
     }
-    Tcl_DStringResult(interp, &savedResult);
+    (void) Tcl_RestoreInterpState(interp, interpState);
     Tcl_DStringFree(&scripts);
 
     Tcl_Release(bindInfoPtr);
@@ -2771,10 +2770,10 @@ GetVirtualEvent(
     Tcl_Obj *virtName)		/* String describing virtual event. */
 {
     Tcl_HashEntry *vhPtr;
-    Tcl_DString ds;
     int iPhys;
     PhysicalsOwned *poPtr;
     Tk_Uid virtUid;
+    Tcl_Obj *resultObj;
 
     virtUid = GetVirtualEventUid(interp, Tcl_GetString(virtName));
     if (virtUid == NULL) {
@@ -2786,15 +2785,13 @@ GetVirtualEvent(
 	return TCL_OK;
     }
 
-    Tcl_DStringInit(&ds);
-
+    resultObj = Tcl_NewObj();
     poPtr = Tcl_GetHashValue(vhPtr);
     for (iPhys = 0; iPhys < poPtr->numOwned; iPhys++) {
-	Tcl_DStringSetLength(&ds, 0);
-	GetPatternString(poPtr->patSeqs[iPhys], &ds);
-	Tcl_AppendElement(interp, Tcl_DStringValue(&ds));
+	Tcl_ListObjAppendElement(NULL, resultObj,
+		GetPatternObj(poPtr->patSeqs[iPhys]));
     }
-    Tcl_DStringFree(&ds);
+    Tcl_SetObjResult(interp, resultObj);
 
     return TCL_OK;
 }
@@ -2824,20 +2821,15 @@ GetAllVirtualEvents(
 {
     Tcl_HashEntry *hPtr;
     Tcl_HashSearch search;
-    Tcl_DString ds;
-
-    Tcl_DStringInit(&ds);
+    Tcl_Obj *resultObj;
 
+    resultObj = Tcl_NewObj();
     hPtr = Tcl_FirstHashEntry(&vetPtr->nameTable, &search);
     for ( ; hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
-	Tcl_DStringSetLength(&ds, 0);
-	Tcl_DStringAppend(&ds, "<<", 2);
-	Tcl_DStringAppend(&ds, Tcl_GetHashKey(hPtr->tablePtr, hPtr), -1);
-	Tcl_DStringAppend(&ds, ">>", 2);
-	Tcl_AppendElement(interp, Tcl_DStringValue(&ds));
+	Tcl_ListObjAppendElement(NULL, resultObj, Tcl_ObjPrintf(
+		"<<%s>>", (char *) Tcl_GetHashKey(hPtr->tablePtr, hPtr)));
     }
-
-    Tcl_DStringFree(&ds);
+    Tcl_SetObjResult(interp, resultObj);
 }
 
 /*
@@ -2924,8 +2916,11 @@ HandleEventGenerate(
     mainPtr = (TkWindow *) mainWin;
     if ((tkwin == NULL)
 	    || (mainPtr->mainPtr != ((TkWindow *) tkwin)->mainPtr)) {
-	Tcl_AppendResult(interp, "window id \"", Tcl_GetString(objv[0]),
-		"\" doesn't exist in this application", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"window id \"%s\" doesn't exist in this application",
+		Tcl_GetString(objv[0])));
+	Tcl_SetErrorCode(interp, "TK", "LOOKUP", "WINDOW",
+		Tcl_GetString(objv[0]), NULL);
 	return TCL_ERROR;
     }
 
@@ -2939,13 +2934,15 @@ HandleEventGenerate(
 	return TCL_ERROR;
     }
     if (count != 1) {
-	Tcl_SetResult(interp, "Double or Triple modifier not allowed",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"Double or Triple modifier not allowed", -1));
+	Tcl_SetErrorCode(interp, "TK", "EVENT", "BAD_MODIFIER", NULL);
 	return TCL_ERROR;
     }
     if (*p != '\0') {
-	Tcl_SetResult(interp, "only one event specification allowed",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"only one event specification allowed", -1));
+	Tcl_SetErrorCode(interp, "TK", "EVENT", "MULTIPLE", NULL);
 	return TCL_ERROR;
     }
 
@@ -3021,8 +3018,9 @@ HandleEventGenerate(
 	     * is missing.
 	     */
 
-	    Tcl_AppendResult(interp, "value for \"", Tcl_GetString(optionPtr),
-		    "\" missing", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "value for \"%s\" missing", Tcl_GetString(optionPtr)));
+	    Tcl_SetErrorCode(interp, "TK", "EVENT", "MISSING_VALUE", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -3163,15 +3161,19 @@ HandleEventGenerate(
 	    value = Tcl_GetString(valuePtr);
 	    keysym = TkStringToKeysym(value);
 	    if (keysym == NoSymbol) {
-		Tcl_AppendResult(interp, "unknown keysym \"", value, "\"",
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"unknown keysym \"%s\"", value));
+		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "KEYSYM", value,
 			NULL);
 		return TCL_ERROR;
 	    }
 
 	    TkpSetKeycodeAndState(tkwin, keysym, &event.general);
 	    if (event.general.xkey.keycode == 0) {
-		Tcl_AppendResult(interp, "no keycode for keysym \"", value,
-			"\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"no keycode for keysym \"%s\"", value));
+		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "KEYCODE", value,
+			NULL);
 		return TCL_ERROR;
 	    }
 	    if (!(flags & KEY)
@@ -3400,8 +3402,10 @@ HandleEventGenerate(
 	continue;
 
     badopt:
-	Tcl_AppendResult(interp, name, " event doesn't accept \"",
-		Tcl_GetString(optionPtr), "\" option", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"%s event doesn't accept \"%s\" option",
+		name, Tcl_GetString(optionPtr)));
+	Tcl_SetErrorCode(interp, "TK", "EVENT", "BAD_OPTION", NULL);
 	return TCL_ERROR;
     }
 
@@ -3495,7 +3499,9 @@ NameToWindow(
     return TCL_OK;
 
   badWindow:
-    Tcl_AppendResult(interp, "bad window name/identifier \"",name,"\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad window name/identifier \"%s\"", name));
+    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "WINDOW_ID", name, NULL);
     return TCL_ERROR;
 }
 
@@ -3558,8 +3564,9 @@ GetVirtualEventUid(
 
     if (length < 5 || virtString[0] != '<' || virtString[1] != '<' ||
 	    virtString[length - 2] != '>' || virtString[length - 1] != '>') {
-	Tcl_AppendResult(interp, "virtual event \"", virtString,
-		"\" is badly formed", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"virtual event \"%s\" is badly formed", virtString));
+	Tcl_SetErrorCode(interp, "TK", "EVENT", "VIRTUAL", "MALFORMED", NULL);
 	return NULL;
     }
     virtString[length - 2] = '\0';
@@ -3651,9 +3658,11 @@ FindSequence(
 
 	if (eventMask & VirtualEventMask) {
 	    if (allowVirtual == 0) {
-		Tcl_SetResult(interp,
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
 			"virtual event not allowed in definition of another virtual event",
-			TCL_STATIC);
+			-1));
+		Tcl_SetErrorCode(interp, "TK", "EVENT", "VIRTUAL", "INNER",
+			NULL);
 		return NULL;
 	    }
 	    virtualFound = 1;
@@ -3679,12 +3688,16 @@ FindSequence(
      */
 
     if (numPats == 0) {
-	Tcl_SetResult(interp, "no events specified in binding", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"no events specified in binding", -1));
+	Tcl_SetErrorCode(interp, "TK", "EVENT", "NO_EVENTS", NULL);
 	return NULL;
     }
     if ((numPats > 1) && (virtualFound != 0)) {
-	Tcl_SetResult(interp, "virtual events may not be composed",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"virtual events may not be composed", -1));
+	Tcl_SetErrorCode(interp, "TK", "EVENT", "VIRTUAL", "COMPOSITION",
+		NULL);
 	return NULL;
     }
 
@@ -3804,6 +3817,7 @@ ParseEventDescription(
 	    } else {
 		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 			"bad ASCII character 0x%x", UCHAR(*p)));
+		Tcl_SetErrorCode(interp, "TK", "EVENT", "BAD_CHAR", NULL);
 		count = 0;
 		goto done;
 	    }
@@ -3844,14 +3858,18 @@ ParseEventDescription(
 
 	p = strchr(field, '>');
 	if (p == field) {
-	    Tcl_SetResult(interp, "virtual event \"<<>>\" is badly formed",
-		    TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "virtual event \"<<>>\" is badly formed", -1));
+	    Tcl_SetErrorCode(interp, "TK", "EVENT", "VIRTUAL", "MALFORMED",
+		    NULL);
 	    count = 0;
 	    goto done;
 	}
 	if ((p == NULL) || (p[1] != '>')) {
-	    Tcl_SetResult(interp, "missing \">\" in virtual binding",
-		    TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "missing \">\" in virtual binding", -1));
+	    Tcl_SetErrorCode(interp, "TK", "EVENT", "VIRTUAL", "MALFORMED",
+		    NULL);
 	    count = 0;
 	    goto done;
 	}
@@ -3917,9 +3935,11 @@ ParseEventDescription(
 		eventMask = ButtonPressMask;
 	    } else if (eventFlags & KEY) {
 		goto getKeysym;
-	    } else if ((eventFlags & BUTTON) == 0) {
-		Tcl_AppendResult(interp, "specified button \"", field,
-			"\" for non-button event", NULL);
+	    } else if (!(eventFlags & BUTTON)) {
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"specified button \"%s\" for non-button event",
+			field));
+		Tcl_SetErrorCode(interp, "TK", "EVENT", "NON_BUTTON", NULL);
 		count = 0;
 		goto done;
 	    }
@@ -3929,24 +3949,28 @@ ParseEventDescription(
 	getKeysym:
 	    patPtr->detail.keySym = TkStringToKeysym(field);
 	    if (patPtr->detail.keySym == NoSymbol) {
-		Tcl_AppendResult(interp, "bad event type or keysym \"",
-			field, "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"bad event type or keysym \"%s\"", field));
+		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "KEYSYM", field,
+			NULL);
 		count = 0;
 		goto done;
 	    }
 	    if (eventFlags == 0) {
 		patPtr->eventType = KeyPress;
 		eventMask = KeyPressMask;
-	    } else if ((eventFlags & KEY) == 0) {
-		Tcl_AppendResult(interp, "specified keysym \"", field,
-			"\" for non-key event", NULL);
+	    } else if (!(eventFlags & KEY)) {
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"specified keysym \"%s\" for non-key event", field));
+		Tcl_SetErrorCode(interp, "TK", "EVENT", "NON_KEY", NULL);
 		count = 0;
 		goto done;
 	    }
 	}
     } else if (eventFlags == 0) {
-	Tcl_SetResult(interp, "no event type or button # or keysym",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"no event type or button # or keysym", -1));
+	Tcl_SetErrorCode(interp, "TK", "EVENT", "UNMODIFIABLE", NULL);
 	count = 0;
 	goto done;
     }
@@ -3958,14 +3982,16 @@ ParseEventDescription(
 	while (*p != '\0') {
 	    p++;
 	    if (*p == '>') {
-		Tcl_SetResult(interp,
-			"extra characters after detail in binding",
-			TCL_STATIC);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"extra characters after detail in binding", -1));
+		Tcl_SetErrorCode(interp, "TK", "EVENT", "PAST_DETAIL", NULL);
 		count = 0;
 		goto done;
 	    }
 	}
-	Tcl_SetResult(interp, "missing \">\" in binding", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"missing \">\" in binding", -1));
+	Tcl_SetErrorCode(interp, "TK", "EVENT", "MALFORMED", NULL);
 	count = 0;
 	goto done;
     }
@@ -4020,31 +4046,30 @@ GetField(
 /*
  *---------------------------------------------------------------------------
  *
- * GetPatternString --
+ * GetPatternObj --
  *
  *	Produce a string version of the given event, for displaying to the
  *	user.
  *
  * Results:
- *	The string is left in dsPtr.
+ *	The string is returned as a Tcl_Obj.
  *
  * Side effects:
- *	It is the caller's responsibility to initialize the DString before and
- *	to free it after calling this function.
+ *	It is the caller's responsibility to arrange for the object to be
+ *	released; it starts with a refCount of zero.
  *
  *---------------------------------------------------------------------------
  */
 
-static void
-GetPatternString(
-    PatSeq *psPtr,
-    Tcl_DString *dsPtr)
+static Tcl_Obj *
+GetPatternObj(
+    PatSeq *psPtr)
 {
     Pattern *patPtr;
-    char c, buffer[TCL_INTEGER_SPACE];
     int patsLeft, needMods;
     const ModInfo *modPtr;
     const EventInfo *eiPtr;
+    Tcl_Obj *patternObj = Tcl_NewObj();
 
     /*
      * The order of the patterns in the sequence is backwards from the order
@@ -4058,14 +4083,15 @@ GetPatternString(
 	 */
 
 	if ((patPtr->eventType == KeyPress)
-		&& ((psPtr->flags & PAT_NEARBY) == 0)
+		&& !(psPtr->flags & PAT_NEARBY)
 		&& (patPtr->needMods == 0)
 		&& (patPtr->detail.keySym < 128)
 		&& isprint(UCHAR(patPtr->detail.keySym))
 		&& (patPtr->detail.keySym != '<')
 		&& (patPtr->detail.keySym != ' ')) {
-	    c = (char) patPtr->detail.keySym;
-	    Tcl_DStringAppend(dsPtr, &c, 1);
+	    char c = (char) patPtr->detail.keySym;
+
+	    Tcl_AppendToObj(patternObj, &c, 1);
 	    continue;
 	}
 
@@ -4074,9 +4100,7 @@ GetPatternString(
 	 */
 
 	if (patPtr->eventType == VirtualEvent) {
-	    Tcl_DStringAppend(dsPtr, "<<", 2);
-	    Tcl_DStringAppend(dsPtr, patPtr->detail.name, -1);
-	    Tcl_DStringAppend(dsPtr, ">>", 2);
+	    Tcl_AppendPrintfToObj(patternObj, "<<%s>>", patPtr->detail.name);
 	    continue;
 	}
 
@@ -4086,7 +4110,7 @@ GetPatternString(
 	 * or button detail.
 	 */
 
-	Tcl_DStringAppend(dsPtr, "<", 1);
+	Tcl_AppendToObj(patternObj, "<", 1);
 
 	if ((psPtr->flags & PAT_NEARBY) && (patsLeft > 1)
 		&& (memcmp(patPtr, patPtr-1, sizeof(Pattern)) == 0)) {
@@ -4100,12 +4124,12 @@ GetPatternString(
 			(memcmp(patPtr, patPtr-1, sizeof(Pattern)) == 0)) {
 		    patsLeft--;
 		    patPtr--;
-		    Tcl_DStringAppend(dsPtr, "Quadruple-", 10);
+		    Tcl_AppendToObj(patternObj, "Quadruple-", 10);
 		} else {
-		    Tcl_DStringAppend(dsPtr, "Triple-", 7);
+		    Tcl_AppendToObj(patternObj, "Triple-", 7);
 		}
 	    } else {
-		Tcl_DStringAppend(dsPtr, "Double-", 7);
+		Tcl_AppendToObj(patternObj, "Double-", 7);
 	    }
 	}
 
@@ -4113,16 +4137,15 @@ GetPatternString(
 		needMods != 0; modPtr++) {
 	    if (modPtr->mask & needMods) {
 		needMods &= ~modPtr->mask;
-		Tcl_DStringAppend(dsPtr, modPtr->name, -1);
-		Tcl_DStringAppend(dsPtr, "-", 1);
+		Tcl_AppendPrintfToObj(patternObj, "%s-", modPtr->name);
 	    }
 	}
 
 	for (eiPtr = eventArray; eiPtr->name != NULL; eiPtr++) {
 	    if (eiPtr->type == patPtr->eventType) {
-		Tcl_DStringAppend(dsPtr, eiPtr->name, -1);
+		Tcl_AppendToObj(patternObj, eiPtr->name, -1);
 		if (patPtr->detail.clientData != 0) {
-		    Tcl_DStringAppend(dsPtr, "-", 1);
+		    Tcl_AppendToObj(patternObj, "-", 1);
 		}
 		break;
 	    }
@@ -4134,16 +4157,17 @@ GetPatternString(
 		const char *string = TkKeysymToString(patPtr->detail.keySym);
 
 		if (string != NULL) {
-		    Tcl_DStringAppend(dsPtr, string, -1);
+		    Tcl_AppendToObj(patternObj, string, -1);
 		}
 	    } else {
-		sprintf(buffer, "%d", patPtr->detail.button);
-		Tcl_DStringAppend(dsPtr, buffer, -1);
+		Tcl_AppendPrintfToObj(patternObj, "%d", patPtr->detail.button);
 	    }
 	}
 
-	Tcl_DStringAppend(dsPtr, ">", 1);
+	Tcl_AppendToObj(patternObj, ">", 1);
     }
+
+    return patternObj;
 }
 
 /*
diff --git a/generic/tkBitmap.c b/generic/tkBitmap.c
index b0d1ecc..729fff4 100644
--- a/generic/tkBitmap.c
+++ b/generic/tkBitmap.c
@@ -342,8 +342,10 @@ GetBitmap(
 	int result;
 
 	if (Tcl_IsSafe(interp)) {
-	    Tcl_AppendResult(interp, "can't specify bitmap with '@' in a",
-		    " safe interpreter", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't specify bitmap with '@' in a safe interpreter",
+		    -1));
+	    Tcl_SetErrorCode(interp, "TK", "SAFE", "BITMAP_FILE", NULL);
 	    goto error;
 	}
 
@@ -363,8 +365,9 @@ GetBitmap(
 		&bitmap, &dummy2, &dummy2);
 	if (result != BitmapSuccess) {
 	    if (interp != NULL) {
-		Tcl_AppendResult(interp, "error reading bitmap file \"",
-			string, "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"error reading bitmap file \"%s\"", string));
+		Tcl_SetErrorCode(interp, "TK", "BITMAP", "FILE_ERROR", NULL);
 	    }
 	    Tcl_DStringFree(&buffer);
 	    goto error;
@@ -384,8 +387,10 @@ GetBitmap(
 
 	    if (bitmap == None) {
 		if (interp != NULL) {
-		    Tcl_AppendResult(interp, "bitmap \"", string,
-			    "\" not defined", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bitmap \"%s\" not defined", string));
+		    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "BITMAP", string,
+			    NULL);
 		}
 		goto error;
 	    }
@@ -487,8 +492,9 @@ Tk_DefineBitmap(
     predefHashPtr = Tcl_CreateHashEntry(&tsdPtr->predefBitmapTable,
 	    name, &isNew);
     if (!isNew) {
-	Tcl_AppendResult(interp, "bitmap \"", name, "\" is already defined",
-		NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bitmap \"%s\" is already defined", name));
+	Tcl_SetErrorCode(interp, "TK", "BITMAP", "EXISTS", NULL);
 	return TCL_ERROR;
     }
     predefPtr = ckalloc(sizeof(TkPredefBitmap));
diff --git a/generic/tkBusy.c b/generic/tkBusy.c
index fc7f6ab..8f73d80 100644
--- a/generic/tkBusy.c
+++ b/generic/tkBusy.c
@@ -687,8 +687,10 @@ GetBusy(
     }
     hPtr = Tcl_FindHashEntry(busyTablePtr, (char *) tkwin);
     if (hPtr == NULL) {
-	Tcl_AppendResult(interp, "can't find busy window \"",
-		Tcl_GetString(windowObj), "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't find busy window \"%s\"", Tcl_GetString(windowObj)));
+	Tcl_SetErrorCode(interp, "TK", "LOOKUP", "BUSY",
+		Tcl_GetString(windowObj), NULL);
 	return NULL;
     }
     return Tcl_GetHashValue(hPtr);
diff --git a/generic/tkCanvArc.c b/generic/tkCanvArc.c
index 6cbc89b..4e4c582 100644
--- a/generic/tkCanvArc.c
+++ b/generic/tkCanvArc.c
@@ -344,27 +344,23 @@ ArcCoords(
     ArcItem *arcPtr = (ArcItem *) itemPtr;
 
     if (objc == 0) {
-	Tcl_Obj *obj = Tcl_NewObj();
-	Tcl_Obj *subobj = Tcl_NewDoubleObj(arcPtr->bbox[0]);
-
-	Tcl_ListObjAppendElement(interp, obj, subobj);
-	subobj = Tcl_NewDoubleObj(arcPtr->bbox[1]);
-	Tcl_ListObjAppendElement(interp, obj, subobj);
-	subobj = Tcl_NewDoubleObj(arcPtr->bbox[2]);
-	Tcl_ListObjAppendElement(interp, obj, subobj);
-	subobj = Tcl_NewDoubleObj(arcPtr->bbox[3]);
-	Tcl_ListObjAppendElement(interp, obj, subobj);
-	Tcl_SetObjResult(interp, obj);
+	Tcl_Obj *objs[4];
+
+	objs[0] = Tcl_NewDoubleObj(arcPtr->bbox[0]);
+	objs[1] = Tcl_NewDoubleObj(arcPtr->bbox[1]);
+	objs[2] = Tcl_NewDoubleObj(arcPtr->bbox[2]);
+	objs[3] = Tcl_NewDoubleObj(arcPtr->bbox[3]);
+	Tcl_SetObjResult(interp, Tcl_NewListObj(4, objs));
     } else if ((objc == 1)||(objc == 4)) {
 	if (objc==1) {
 	    if (Tcl_ListObjGetElements(interp, objv[0], &objc,
 		    (Tcl_Obj ***) &objv) != TCL_OK) {
 		return TCL_ERROR;
 	    } else if (objc != 4) {
-		char buf[64 + TCL_INTEGER_SPACE];
-
-		sprintf(buf, "wrong # coordinates: expected 4, got %d", objc);
-		Tcl_SetResult(interp, buf, TCL_VOLATILE);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"wrong # coordinates: expected 4, got %d", objc));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "ARC",
+			NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -380,10 +376,9 @@ ArcCoords(
 	}
 	ComputeArcBbox(canvas, arcPtr);
     } else {
-	char buf[64 + TCL_INTEGER_SPACE];
-
-	sprintf(buf, "wrong # coordinates: expected 0 or 4, got %d", objc);
-	Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"wrong # coordinates: expected 0 or 4, got %d", objc));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "ARC", NULL);
 	return TCL_ERROR;
     }
     return TCL_OK;
@@ -1823,13 +1818,14 @@ ArcToPostscript(
 				 * being created. */
 {
     ArcItem *arcPtr = (ArcItem *) itemPtr;
-    char buffer[400];
     double y1, y2, ang1, ang2;
     XColor *color;
     Pixmap stipple;
     XColor *fillColor;
     Pixmap fillStipple;
     Tk_State state = itemPtr->state;
+    Tcl_Obj *psObj;
+    Tcl_InterpState interpState;
 
     y1 = Tk_CanvasPsY(canvas, arcPtr->bbox[1]);
     y2 = Tk_CanvasPsY(canvas, arcPtr->bbox[3]);
@@ -1876,37 +1872,51 @@ ArcToPostscript(
     }
 
     /*
+     * Make our working space.
+     */
+
+    psObj = Tcl_NewObj();
+    interpState = Tcl_SaveInterpState(interp, TCL_OK);
+
+    /*
      * If the arc is filled, output Postscript for the interior region of the
      * arc.
      */
 
     if (arcPtr->fillGC != None) {
-	sprintf(buffer, "matrix currentmatrix\n%.15g %.15g translate %.15g %.15g scale\n",
+	Tcl_AppendPrintfToObj(psObj,
+		"matrix currentmatrix\n"
+		"%.15g %.15g translate %.15g %.15g scale\n",
 		(arcPtr->bbox[0] + arcPtr->bbox[2])/2, (y1 + y2)/2,
 		(arcPtr->bbox[2] - arcPtr->bbox[0])/2, (y1 - y2)/2);
-	Tcl_AppendResult(interp, buffer, NULL);
-	if (arcPtr->style == CHORD_STYLE) {
-	    sprintf(buffer, "0 0 1 %.15g %.15g arc closepath\nsetmatrix\n",
-		    ang1, ang2);
-	} else {
-	    sprintf(buffer,
-		    "0 0 moveto 0 0 1 %.15g %.15g arc closepath\nsetmatrix\n",
-		    ang1, ang2);
+
+	if (arcPtr->style != CHORD_STYLE) {
+	    Tcl_AppendToObj(psObj, "0 0 moveto ", -1);
 	}
-	Tcl_AppendResult(interp, buffer, NULL);
+	Tcl_AppendPrintfToObj(psObj,
+		"0 0 1 %.15g %.15g arc closepath\nsetmatrix\n",
+		ang1, ang2);
+
+	Tcl_ResetResult(interp);
 	if (Tk_CanvasPsColor(interp, canvas, fillColor) != TCL_OK) {
-	    return TCL_ERROR;
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	if (fillStipple != None) {
-	    Tcl_AppendResult(interp, "clip ", NULL);
+	    Tcl_AppendToObj(psObj, "clip ", -1);
+
+	    Tcl_ResetResult(interp);
 	    if (Tk_CanvasPsStipple(interp, canvas, fillStipple) != TCL_OK) {
-		return TCL_ERROR;
+		goto error;
 	    }
+	    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	    if (arcPtr->outline.gc != None) {
-		Tcl_AppendResult(interp, "grestore gsave\n", NULL);
+		Tcl_AppendToObj(psObj, "grestore gsave\n", -1);
 	    }
 	} else {
-	    Tcl_AppendResult(interp, "fill\n", NULL);
+	    Tcl_AppendToObj(psObj, "fill\n", -1);
 	}
     }
 
@@ -1915,57 +1925,86 @@ ArcToPostscript(
      */
 
     if (arcPtr->outline.gc != None) {
-	sprintf(buffer, "matrix currentmatrix\n%.15g %.15g translate %.15g %.15g scale\n",
+	Tcl_AppendPrintfToObj(psObj,
+		"matrix currentmatrix\n"
+		"%.15g %.15g translate %.15g %.15g scale\n",
 		(arcPtr->bbox[0] + arcPtr->bbox[2])/2, (y1 + y2)/2,
 		(arcPtr->bbox[2] - arcPtr->bbox[0])/2, (y1 - y2)/2);
-	Tcl_AppendResult(interp, buffer, NULL);
-	sprintf(buffer, "0 0 1 %.15g %.15g", ang1, ang2);
-	Tcl_AppendResult(interp, buffer,
-		" arc\nsetmatrix\n0 setlinecap\n", NULL);
-	if (Tk_CanvasPsOutline(canvas, itemPtr, &(arcPtr->outline)) != TCL_OK){
-	    return TCL_ERROR;
+	Tcl_AppendPrintfToObj(psObj,
+		"0 0 1 %.15g %.15g arc\nsetmatrix\n0 setlinecap\n",
+		ang1, ang2);
+
+	Tcl_ResetResult(interp);
+	if (Tk_CanvasPsOutline(canvas, itemPtr, &arcPtr->outline) != TCL_OK) {
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	if (arcPtr->style != ARC_STYLE) {
-	    Tcl_AppendResult(interp, "grestore gsave\n", NULL);
+	    Tcl_AppendToObj(psObj, "grestore gsave\n", -1);
+
+	    Tcl_ResetResult(interp);
 	    if (arcPtr->style == CHORD_STYLE) {
 		Tk_CanvasPsPath(interp, canvas, arcPtr->outlinePtr,
 			CHORD_OUTLINE_PTS);
 	    } else {
 		Tk_CanvasPsPath(interp, canvas, arcPtr->outlinePtr,
 			PIE_OUTLINE1_PTS);
-		if (Tk_CanvasPsColor(interp, canvas, color)
-			!= TCL_OK) {
-		    return TCL_ERROR;
+		if (Tk_CanvasPsColor(interp, canvas, color) != TCL_OK) {
+		    goto error;
 		}
+		Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 		if (stipple != None) {
-		    Tcl_AppendResult(interp, "clip ", NULL);
-		    if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK){
-			return TCL_ERROR;
+		    Tcl_AppendToObj(psObj, "clip ", -1);
+
+		    Tcl_ResetResult(interp);
+		    if (Tk_CanvasPsStipple(interp, canvas, stipple) !=TCL_OK){
+			goto error;
 		    }
+		    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
 		} else {
-		    Tcl_AppendResult(interp, "fill\n", NULL);
+		    Tcl_AppendToObj(psObj, "fill\n", -1);
 		}
-		Tcl_AppendResult(interp, "grestore gsave\n", NULL);
+		Tcl_AppendToObj(psObj, "grestore gsave\n", -1);
+
+		Tcl_ResetResult(interp);
 		Tk_CanvasPsPath(interp, canvas,
 			arcPtr->outlinePtr + 2*PIE_OUTLINE1_PTS,
 			PIE_OUTLINE2_PTS);
 	    }
-	    if (Tk_CanvasPsColor(interp, canvas, color)
-		    != TCL_OK) {
-		return TCL_ERROR;
+	    if (Tk_CanvasPsColor(interp, canvas, color) != TCL_OK) {
+		goto error;
 	    }
+	    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	    if (stipple != None) {
-		Tcl_AppendResult(interp, "clip ", NULL);
+		Tcl_AppendToObj(psObj, "clip ", -1);
+
+		Tcl_ResetResult(interp);
 		if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK) {
-		    return TCL_ERROR;
+		    goto error;
 		}
+		Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
 	    } else {
-		Tcl_AppendResult(interp, "fill\n", NULL);
+		Tcl_AppendToObj(psObj, "fill\n", -1);
 	    }
 	}
     }
 
+    /*
+     * Plug the accumulated postscript back into the result.
+     */
+
+    (void) Tcl_RestoreInterpState(interp, interpState);
+    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    Tcl_DecrRefCount(psObj);
     return TCL_OK;
+
+  error:
+    Tcl_DiscardInterpState(interpState);
+    Tcl_DecrRefCount(psObj);
+    return TCL_ERROR;
 }
 
 /*
@@ -2021,8 +2060,10 @@ StyleParseProc(
 	return TCL_OK;
     }
 
-    Tcl_AppendResult(interp, "bad -style option \"", value,
-	    "\": must be arc, chord, or pieslice", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad -style option \"%s\": must be arc, chord, or pieslice",
+	    value));
+    Tcl_SetErrorCode(interp, "TK", "CANVAS", "ARC_STYLE", NULL);
     *stylePtr = PIESLICE_STYLE;
     return TCL_ERROR;
 }
diff --git a/generic/tkCanvBmap.c b/generic/tkCanvBmap.c
index ea16a29..d7d54f4 100644
--- a/generic/tkCanvBmap.c
+++ b/generic/tkCanvBmap.c
@@ -249,10 +249,8 @@ BitmapCoords(
     if (objc == 0) {
 	Tcl_Obj *obj = Tcl_NewObj();
 
-	Tcl_Obj *subobj = Tcl_NewDoubleObj(bmapPtr->x);
-	Tcl_ListObjAppendElement(interp, obj, subobj);
-	subobj = Tcl_NewDoubleObj(bmapPtr->y);
-	Tcl_ListObjAppendElement(interp, obj, subobj);
+	Tcl_ListObjAppendElement(NULL, obj, Tcl_NewDoubleObj(bmapPtr->x));
+	Tcl_ListObjAppendElement(NULL, obj, Tcl_NewDoubleObj(bmapPtr->y));
 	Tcl_SetObjResult(interp, obj);
     } else if (objc < 3) {
 	if (objc == 1) {
@@ -260,10 +258,10 @@ BitmapCoords(
 		    (Tcl_Obj ***) &objv) != TCL_OK) {
 		return TCL_ERROR;
 	    } else if (objc != 2) {
-		char buf[64 + TCL_INTEGER_SPACE];
-
-		sprintf(buf, "wrong # coordinates: expected 2, got %d", objc);
-		Tcl_SetResult(interp, buf, TCL_VOLATILE);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"wrong # coordinates: expected 2, got %d", objc));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "BITMAP",
+			NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -275,10 +273,9 @@ BitmapCoords(
 	}
 	ComputeBitmapBbox(canvas, bmapPtr);
     } else {
-	char buf[64 + TCL_INTEGER_SPACE];
-
-	sprintf(buf, "wrong # coordinates: expected 0 or 2, got %d", objc);
-	Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"wrong # coordinates: expected 0 or 2, got %d", objc));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "BITMAP", NULL);
 	return TCL_ERROR;
     }
     return TCL_OK;
@@ -853,11 +850,12 @@ BitmapToPostscript(
     double x, y;
     int width, height, rowsAtOnce, rowsThisTime;
     int curRow;
-    char buffer[100 + TCL_DOUBLE_SPACE * 2 + TCL_INTEGER_SPACE * 4];
     XColor *fgColor;
     XColor *bgColor;
     Pixmap bitmap;
     Tk_State state = itemPtr->state;
+    Tcl_Obj *psObj;
+    Tcl_InterpState interpState;
 
     if (state == TK_STATE_NULL) {
 	state = Canvas(canvas)->canvas_state;
@@ -913,18 +911,29 @@ BitmapToPostscript(
     }
 
     /*
+     * Make our working space.
+     */
+
+    psObj = Tcl_NewObj();
+    interpState = Tcl_SaveInterpState(interp, TCL_OK);
+
+    /*
      * Color the background, if there is one.
      */
 
     if (bgColor != NULL) {
-	sprintf(buffer,
-		"%.15g %.15g moveto %d 0 rlineto 0 %d rlineto %d %s\n",
-		x, y, width, height, -width, "0 rlineto closepath");
-	Tcl_AppendResult(interp, buffer, NULL);
+	Tcl_AppendPrintfToObj(psObj,
+		"%.15g %.15g moveto %d 0 rlineto 0 %d rlineto "
+		"%d 0 rlineto closepath\n",
+		x, y, width, height, -width);
+
+	Tcl_ResetResult(interp);
 	if (Tk_CanvasPsColor(interp, canvas, bgColor) != TCL_OK) {
-	    return TCL_ERROR;
+	    goto error;
 	}
-	Tcl_AppendResult(interp, "fill\n", NULL);
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
+	Tcl_AppendToObj(psObj, "fill\n", -1);
     }
 
     /*
@@ -935,37 +944,61 @@ BitmapToPostscript(
      */
 
     if (fgColor != NULL) {
+	Tcl_ResetResult(interp);
 	if (Tk_CanvasPsColor(interp, canvas, fgColor) != TCL_OK) {
-	    return TCL_ERROR;
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	if (width > 60000) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "can't generate Postscript",
-		    " for bitmaps more than 60000 pixels wide", NULL);
-	    return TCL_ERROR;
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't generate Postscript for bitmaps more than 60000"
+		    " pixels wide", -1));
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "MEMLIMIT", NULL);
+	    goto error;
 	}
+
 	rowsAtOnce = 60000/width;
 	if (rowsAtOnce < 1) {
 	    rowsAtOnce = 1;
 	}
-	sprintf(buffer, "%.15g %.15g translate\n", x, y+height);
-	Tcl_AppendResult(interp, buffer, NULL);
+
+	Tcl_AppendPrintfToObj(psObj, "%.15g %.15g translate\n", x, y+height);
+
 	for (curRow = 0; curRow < height; curRow += rowsAtOnce) {
 	    rowsThisTime = rowsAtOnce;
 	    if (rowsThisTime > (height - curRow)) {
 		rowsThisTime = height - curRow;
 	    }
-	    sprintf(buffer, "0 -%.15g translate\n%d %d true matrix {\n",
+
+	    Tcl_AppendPrintfToObj(psObj,
+		    "0 -%.15g translate\n%d %d true matrix {\n",
 		    (double) rowsThisTime, width, rowsThisTime);
-	    Tcl_AppendResult(interp, buffer, NULL);
+
+	    Tcl_ResetResult(interp);
 	    if (Tk_CanvasPsBitmap(interp, canvas, bitmap,
 		    0, curRow, width, rowsThisTime) != TCL_OK) {
-		return TCL_ERROR;
+		goto error;
 	    }
-	    Tcl_AppendResult(interp, "\n} imagemask\n", NULL);
+	    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
+	    Tcl_AppendToObj(psObj, "\n} imagemask\n", -1);
 	}
     }
+
+    /*
+     * Plug the accumulated postscript back into the result.
+     */
+
+    (void) Tcl_RestoreInterpState(interp, interpState);
+    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    Tcl_DecrRefCount(psObj);
     return TCL_OK;
+
+  error:
+    Tcl_DiscardInterpState(interpState);
+    Tcl_DecrRefCount(psObj);
+    return TCL_ERROR;
 }
 
 /*
diff --git a/generic/tkCanvImg.c b/generic/tkCanvImg.c
index 880070b..899741a 100644
--- a/generic/tkCanvImg.c
+++ b/generic/tkCanvImg.c
@@ -232,37 +232,35 @@ ImageCoords(
     ImageItem *imgPtr = (ImageItem *) itemPtr;
 
     if (objc == 0) {
-	Tcl_Obj *obj = Tcl_NewObj();
+	Tcl_Obj *objs[2];
 
-	Tcl_Obj *subobj = Tcl_NewDoubleObj(imgPtr->x);
-	Tcl_ListObjAppendElement(interp, obj, subobj);
-	subobj = Tcl_NewDoubleObj(imgPtr->y);
-	Tcl_ListObjAppendElement(interp, obj, subobj);
-	Tcl_SetObjResult(interp, obj);
+	objs[0] = Tcl_NewDoubleObj(imgPtr->x);
+	objs[1] = Tcl_NewDoubleObj(imgPtr->y);
+	Tcl_SetObjResult(interp, Tcl_NewListObj(2, objs));
     } else if (objc < 3) {
 	if (objc==1) {
 	    if (Tcl_ListObjGetElements(interp, objv[0], &objc,
 		    (Tcl_Obj ***) &objv) != TCL_OK) {
 		return TCL_ERROR;
 	    } else if (objc != 2) {
-		char buf[64];
-
-		sprintf(buf, "wrong # coordinates: expected 2, got %d", objc);
-		Tcl_SetResult(interp, buf, TCL_VOLATILE);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"wrong # coordinates: expected 2, got %d", objc));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "IMAGE",
+			NULL);
 		return TCL_ERROR;
 	    }
 	}
-	if ((Tk_CanvasGetCoordFromObj(interp, canvas, objv[0], &imgPtr->x) != TCL_OK)
+	if ((Tk_CanvasGetCoordFromObj(interp, canvas, objv[0],
+		    &imgPtr->x) != TCL_OK)
 		|| (Tk_CanvasGetCoordFromObj(interp, canvas, objv[1],
   		    &imgPtr->y) != TCL_OK)) {
 	    return TCL_ERROR;
 	}
 	ComputeImageBbox(canvas, imgPtr);
     } else {
-	char buf[64];
-
-	sprintf(buf, "wrong # coordinates: expected 0 or 2, got %d", objc);
-	Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"wrong # coordinates: expected 0 or 2, got %d", objc));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "IMAGE", NULL);
 	return TCL_ERROR;
     }
     return TCL_OK;
@@ -697,14 +695,12 @@ ImageToPostscript(
 {
     ImageItem *imgPtr = (ImageItem *) itemPtr;
     Tk_Window canvasWin = Tk_CanvasTkwin(canvas);
-
-    char buffer[256];
     double x, y;
     int width, height;
     Tk_Image image;
     Tk_State state = itemPtr->state;
 
-    if(state == TK_STATE_NULL) {
+    if (state == TK_STATE_NULL) {
 	state = Canvas(canvas)->canvas_state;
     }
 
@@ -748,8 +744,14 @@ ImageToPostscript(
     }
 
     if (!prepass) {
-	sprintf(buffer, "%.15g %.15g", x, y);
-	Tcl_AppendResult(interp, buffer, " translate\n", NULL);
+	Tcl_Obj *psObj = Tcl_GetObjResult(interp);
+
+	if (Tcl_IsShared(psObj)) {
+	    psObj = Tcl_DuplicateObj(psObj);
+	    Tcl_SetObjResult(interp, psObj);
+	}
+
+	Tcl_AppendPrintfToObj(psObj, "%.15g %.15g translate\n", x, y);
     }
 
     return Tk_PostscriptImage(image, interp, canvasWin,
diff --git a/generic/tkCanvLine.c b/generic/tkCanvLine.c
index 20a391e..9d68c37 100644
--- a/generic/tkCanvLine.c
+++ b/generic/tkCanvLine.c
@@ -75,7 +75,7 @@ typedef struct LineItem {
 
 static int		ArrowheadPostscript(Tcl_Interp *interp,
 			    Tk_Canvas canvas, LineItem *linePtr,
-			    double *arrowPtr);
+			    double *arrowPtr, Tcl_Obj *psObj);
 static void		ComputeLineBbox(Tk_Canvas canvas, LineItem *linePtr);
 static int		ConfigureLine(Tcl_Interp *interp,
 			    Tk_Canvas canvas, Tk_Item *itemPtr, int objc,
@@ -391,54 +391,52 @@ LineCoords(
 	}
     }
     if (objc & 1) {
-	char buf[64 + TCL_INTEGER_SPACE];
-
-	sprintf(buf, "wrong # coordinates: expected an even number, got %d",
-		objc);
-	Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"wrong # coordinates: expected an even number, got %d",
+		objc));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "LINE", NULL);
 	return TCL_ERROR;
     } else if (objc < 4) {
-	char buf[64 + TCL_INTEGER_SPACE];
-
-	sprintf(buf, "wrong # coordinates: expected at least 4, got %d", objc);
-	Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"wrong # coordinates: expected at least 4, got %d", objc));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "LINE", NULL);
 	return TCL_ERROR;
-    } else {
-	numPoints = objc/2;
-	if (linePtr->numPoints != numPoints) {
-	    coordPtr = ckalloc(sizeof(double) * objc);
-	    if (linePtr->coordPtr != NULL) {
-		ckfree(linePtr->coordPtr);
-	    }
-	    linePtr->coordPtr = coordPtr;
-	    linePtr->numPoints = numPoints;
+    }
+
+    numPoints = objc/2;
+    if (linePtr->numPoints != numPoints) {
+	coordPtr = ckalloc(sizeof(double) * objc);
+	if (linePtr->coordPtr != NULL) {
+	    ckfree(linePtr->coordPtr);
 	}
-	coordPtr = linePtr->coordPtr;
-	for (i = 0; i < objc ; i++) {
-	    if (Tk_CanvasGetCoordFromObj(interp, canvas, objv[i],
-		    coordPtr++) != TCL_OK) {
-		return TCL_ERROR;
-	    }
+	linePtr->coordPtr = coordPtr;
+	linePtr->numPoints = numPoints;
+    }
+    coordPtr = linePtr->coordPtr;
+    for (i = 0; i < objc ; i++) {
+	if (Tk_CanvasGetCoordFromObj(interp, canvas, objv[i],
+		coordPtr++) != TCL_OK) {
+	    return TCL_ERROR;
 	}
+    }
 
-	/*
-	 * Update arrowheads by throwing away any existing arrow-head
-	 * information and calling ConfigureArrows to recompute it.
-	 */
+    /*
+     * Update arrowheads by throwing away any existing arrow-head information
+     * and calling ConfigureArrows to recompute it.
+     */
 
-	if (linePtr->firstArrowPtr != NULL) {
-	    ckfree(linePtr->firstArrowPtr);
-	    linePtr->firstArrowPtr = NULL;
-	}
-	if (linePtr->lastArrowPtr != NULL) {
-	    ckfree(linePtr->lastArrowPtr);
-	    linePtr->lastArrowPtr = NULL;
-	}
-	if (linePtr->arrow != ARROWS_NONE) {
-	    ConfigureArrows(canvas, linePtr);
-	}
-	ComputeLineBbox(canvas, linePtr);
+    if (linePtr->firstArrowPtr != NULL) {
+	ckfree(linePtr->firstArrowPtr);
+	linePtr->firstArrowPtr = NULL;
+    }
+    if (linePtr->lastArrowPtr != NULL) {
+	ckfree(linePtr->lastArrowPtr);
+	linePtr->lastArrowPtr = NULL;
     }
+    if (linePtr->arrow != ARROWS_NONE) {
+	ConfigureArrows(canvas, linePtr);
+    }
+    ComputeLineBbox(canvas, linePtr);
     return TCL_OK;
 }
 
@@ -1752,15 +1750,7 @@ GetLineIndex(
 	if (strncmp(string, "end", (unsigned) length) == 0) {
 	    *indexPtr = 2*linePtr->numPoints;
 	} else {
-	    /*
-	     * Some of the paths here leave messages in interp->result, so we
-	     * have to clear it out before storing our own message.
-	     */
-
-	badIndex:
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "bad index \"", string, "\"", NULL);
-	    return TCL_ERROR;
+	    goto badIndex;
 	}
     } else if (string[0] == '@') {
 	int i;
@@ -1801,6 +1791,17 @@ GetLineIndex(
 	}
     }
     return TCL_OK;
+
+    /*
+     * Some of the paths here leave messages in interp->result, so we have to
+     * clear it out before storing our own message.
+     */
+
+  badIndex:
+    Tcl_ResetResult(interp);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf("bad index \"%s\"", string));
+    Tcl_SetErrorCode(interp, "TK", "CANVAS", "ITEM_INDEX", "LINE", NULL);
+    return TCL_ERROR;
 }
 
 /*
@@ -1894,16 +1895,8 @@ ParseArrowShape(
     }
 
     if (Tcl_SplitList(interp, (char *) value, &argc, &argv) != TCL_OK) {
-	syntaxError:
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "bad arrow shape \"", value,
-		"\": must be list with three numbers", NULL);
-	if (argv != NULL) {
-	    ckfree(argv);
-	}
-	return TCL_ERROR;
-    }
-    if (argc != 3) {
+	goto syntaxError;
+    } else if (argc != 3) {
 	goto syntaxError;
     }
     if ((Tk_CanvasGetCoord(interp, linePtr->canvas, argv[0], &a) != TCL_OK)
@@ -1913,11 +1906,23 @@ ParseArrowShape(
 		!= TCL_OK)) {
 	goto syntaxError;
     }
+
     linePtr->arrowShapeA = (float) a;
     linePtr->arrowShapeB = (float) b;
     linePtr->arrowShapeC = (float) c;
     ckfree(argv);
     return TCL_OK;
+
+  syntaxError:
+    Tcl_ResetResult(interp);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad arrow shape \"%s\": must be list with three numbers",
+	    value));
+    Tcl_SetErrorCode(interp, "TK", "CANVAS", "ARROW_SHAPE", NULL);
+    if (argv != NULL) {
+	ckfree(argv);
+    }
+    return TCL_ERROR;
 }
 
 /*
@@ -2014,8 +2019,10 @@ ArrowParseProc(
 	return TCL_OK;
     }
 
-    Tcl_AppendResult(interp, "bad arrow spec \"", value,
-	    "\": must be none, first, last, or both", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad arrow spec \"%s\": must be none, first, last, or both",
+	    value));
+    Tcl_SetErrorCode(interp, "TK", "CANVAS", "ARROW", NULL);
     *arrowPtr = ARROWS_NONE;
     return TCL_ERROR;
 }
@@ -2252,13 +2259,13 @@ LineToPostscript(
 				 * being created. */
 {
     LineItem *linePtr = (LineItem *) itemPtr;
-    char buffer[64 + TCL_INTEGER_SPACE];
-    const char *style;
-
+    int style;
     double width;
     XColor *color;
     Pixmap stipple;
     Tk_State state = itemPtr->state;
+    Tcl_Obj *psObj;
+    Tcl_InterpState interpState;
 
     if (state == TK_STATE_NULL) {
 	state = Canvas(canvas)->canvas_state;
@@ -2293,30 +2300,50 @@ LineToPostscript(
 	return TCL_OK;
     }
 
+    /*
+     * Make our working space.
+     */
+
+    psObj = Tcl_NewObj();
+    interpState = Tcl_SaveInterpState(interp, TCL_OK);
+
+    /*
+     * Check if we're just doing a "pixel".
+     */
+
     if (linePtr->numPoints == 1) {
-	sprintf(buffer, "%.15g %.15g translate %.15g %.15g",
+	Tcl_AppendToObj(psObj, "matrix currentmatrix\n", -1);
+	Tcl_AppendPrintfToObj(psObj, "%.15g %.15g translate %.15g %.15g",
 		linePtr->coordPtr[0], Tk_CanvasPsY(canvas, linePtr->coordPtr[1]),
 		width/2.0, width/2.0);
-	Tcl_AppendResult(interp, "matrix currentmatrix\n", buffer,
-		" scale 1 0 moveto 0 0 1 0 360 arc\nsetmatrix\n", NULL);
+	Tcl_AppendToObj(psObj,
+		" scale 1 0 moveto 0 0 1 0 360 arc\nsetmatrix\n", -1);
+
+	Tcl_ResetResult(interp);
 	if (Tk_CanvasPsColor(interp, canvas, color) != TCL_OK) {
-	    return TCL_ERROR;
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	if (stipple != None) {
-	    Tcl_AppendResult(interp, "clip ", NULL);
+	    Tcl_AppendToObj(psObj, "clip ", -1);
+	    Tcl_ResetResult(interp);
 	    if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK) {
-		return TCL_ERROR;
+		goto error;
 	    }
+	    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
 	} else {
-	    Tcl_AppendResult(interp, "fill\n", NULL);
+	    Tcl_AppendToObj(psObj, "fill\n", -1);
 	}
-	return TCL_OK;
+	goto done;
     }
+
     /*
      * Generate a path for the line's center-line (do this differently for
      * straight lines and smoothed lines).
      */
 
+    Tcl_ResetResult(interp);
     if ((!linePtr->smooth) || (linePtr->numPoints < 3)) {
 	Tk_CanvasPsPath(interp, canvas, linePtr->coordPtr, linePtr->numPoints);
     } else if ((stipple == None) && linePtr->smooth->postscriptProc) {
@@ -2348,29 +2375,34 @@ LineToPostscript(
 	    ckfree(pointPtr);
 	}
     }
+    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
 
     /*
      * Set other line-drawing parameters and stroke out the line.
      */
 
-    style = "0 setlinecap\n";
     if (linePtr->capStyle == CapRound) {
-	style = "1 setlinecap\n";
+	style = 1;
     } else if (linePtr->capStyle == CapProjecting) {
-	style = "2 setlinecap\n";
+	style = 2;
+    } else {
+	style = 0;
     }
-    Tcl_AppendResult(interp, style, NULL);
-    style = "0 setlinejoin\n";
+    Tcl_AppendPrintfToObj(psObj, "%d setlinecap\n", style);
     if (linePtr->joinStyle == JoinRound) {
-	style = "1 setlinejoin\n";
+	style = 1;
     } else if (linePtr->joinStyle == JoinBevel) {
-	style = "2 setlinejoin\n";
+	style = 2;
+    } else {
+	style = 0;
     }
-    Tcl_AppendResult(interp, style, NULL);
+    Tcl_AppendPrintfToObj(psObj, "%d setlinejoin\n", style);
 
+    Tcl_ResetResult(interp);
     if (Tk_CanvasPsOutline(canvas, itemPtr, &linePtr->outline) != TCL_OK) {
-	return TCL_ERROR;
+	goto error;
     }
+    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
 
     /*
      * Output polygons for the arrowheads, if there are any.
@@ -2378,23 +2410,37 @@ LineToPostscript(
 
     if (linePtr->firstArrowPtr != NULL) {
 	if (stipple != None) {
-	    Tcl_AppendResult(interp, "grestore gsave\n", NULL);
+	    Tcl_AppendToObj(psObj, "grestore gsave\n", -1);
 	}
 	if (ArrowheadPostscript(interp, canvas, linePtr,
-		linePtr->firstArrowPtr) != TCL_OK) {
-	    return TCL_ERROR;
+		linePtr->firstArrowPtr, psObj) != TCL_OK) {
+	    goto error;
 	}
     }
     if (linePtr->lastArrowPtr != NULL) {
 	if (stipple != None) {
-	    Tcl_AppendResult(interp, "grestore gsave\n", NULL);
+	    Tcl_AppendToObj(psObj, "grestore gsave\n", -1);
 	}
 	if (ArrowheadPostscript(interp, canvas, linePtr,
-		linePtr->lastArrowPtr) != TCL_OK) {
-	    return TCL_ERROR;
+		linePtr->lastArrowPtr, psObj) != TCL_OK) {
+	    goto error;
 	}
     }
+
+    /*
+     * Plug the accumulated postscript back into the result.
+     */
+
+  done:
+    (void) Tcl_RestoreInterpState(interp, interpState);
+    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    Tcl_DecrRefCount(psObj);
     return TCL_OK;
+
+  error:
+    Tcl_DiscardInterpState(interpState);
+    Tcl_DecrRefCount(psObj);
+    return TCL_ERROR;
 }
 
 /*
@@ -2409,7 +2455,7 @@ LineToPostscript(
  *	The return value is a standard Tcl result. If an error occurs in
  *	generating Postscript then an error message is left in the interp's
  *	result, replacing whatever used to be there. If no error occurs, then
- *	Postscript for the arrowhead is appended to the result.
+ *	Postscript for the arrowhead is appended to the given object.
  *
  * Side effects:
  *	None.
@@ -2419,12 +2465,14 @@ LineToPostscript(
 
 static int
 ArrowheadPostscript(
-    Tcl_Interp *interp,		/* Leave Postscript or error message here. */
+    Tcl_Interp *interp,		/* Leave error message here; non-error results
+				 * will be discarded by caller. */
     Tk_Canvas canvas,		/* Information about overall canvas. */
     LineItem *linePtr,		/* Line item for which Postscript is being
 				 * generated. */
-    double *arrowPtr)		/* Pointer to first of five points describing
+    double *arrowPtr,		/* Pointer to first of five points describing
 				 * arrowhead polygon. */
+    Tcl_Obj *psObj)		/* Append postscript to this object. */
 {
     Pixmap stipple;
     Tk_State state = linePtr->header.state;
@@ -2444,14 +2492,20 @@ ArrowheadPostscript(
 	}
     }
 
+    Tcl_ResetResult(interp);
     Tk_CanvasPsPath(interp, canvas, arrowPtr, PTS_IN_ARROW);
+    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
     if (stipple != None) {
-	Tcl_AppendResult(interp, "clip ", NULL);
+	Tcl_AppendToObj(psObj, "clip ", -1);
+
+	Tcl_ResetResult(interp);
 	if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK) {
 	    return TCL_ERROR;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
     } else {
-	Tcl_AppendResult(interp, "fill\n", NULL);
+	Tcl_AppendToObj(psObj, "fill\n", -1);
     }
     return TCL_OK;
 }
diff --git a/generic/tkCanvPoly.c b/generic/tkCanvPoly.c
index 943ef0b..f8ea42b 100644
--- a/generic/tkCanvPoly.c
+++ b/generic/tkCanvPoly.c
@@ -359,6 +359,7 @@ PolygonCoords(
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"wrong # coordinates: expected an even number, got %d",
 		objc));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "POLYGON", NULL);
 	return TCL_ERROR;
     }
 
@@ -1731,6 +1732,7 @@ GetPolygonIndex(
 
   badIndex:
     Tcl_SetObjResult(interp, Tcl_ObjPrintf("bad index \"%s\"", string));
+    Tcl_SetErrorCode(interp, "TK", "CANVAS", "ITEM_INDEX", "POLY", NULL);
     return TCL_ERROR;
 }
 
@@ -1799,13 +1801,15 @@ PolygonToPostscript(
 				 * being created. */
 {
     PolygonItem *polyPtr = (PolygonItem *) itemPtr;
-    const char *style;
+    int style;
     XColor *color;
     XColor *fillColor;
     Pixmap stipple;
     Pixmap fillStipple;
     Tk_State state = itemPtr->state;
     double width;
+    Tcl_Obj *psObj;
+    Tcl_InterpState interpState;
 
     if (polyPtr->numPoints < 2 || polyPtr->coordPtr == NULL) {
 	return TCL_OK;
@@ -1852,9 +1856,17 @@ PolygonToPostscript(
 	    fillStipple = polyPtr->disabledFillStipple;
 	}
     }
+
+    /*
+     * Make our working space.
+     */
+
+    psObj = Tcl_NewObj();
+    interpState = Tcl_SaveInterpState(interp, TCL_OK);
+
     if (polyPtr->numPoints == 2) {
 	if (color == NULL) {
-	    return TCL_OK;
+	    goto done;
 	}
 
 	/*
@@ -1862,7 +1874,7 @@ PolygonToPostscript(
 	 * tiny to be used directly...)
 	 */
 
-	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	Tcl_AppendPrintfToObj(psObj,
 		"matrix currentmatrix\n"	/* save state */
 		"%.15g %.15g translate "	/* go to drawing location */
 		"%.15g %.15g scale "		/* scale the drawing */
@@ -1871,24 +1883,30 @@ PolygonToPostscript(
 		"setmatrix\n",			/* restore state */
 		polyPtr->coordPtr[0],
 		Tk_CanvasPsY(canvas, polyPtr->coordPtr[1]),
-		width/2.0, width/2.0));
+		width/2.0, width/2.0);
 
 	/*
 	 * Color it in.
 	 */
 
+	Tcl_ResetResult(interp);
 	if (Tk_CanvasPsColor(interp, canvas, color) != TCL_OK) {
-	    return TCL_ERROR;
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	if (stipple != None) {
-	    Tcl_AppendResult(interp, "clip ", NULL);
+	    Tcl_AppendToObj(psObj, "clip ", -1);
+
+	    Tcl_ResetResult(interp);
 	    if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK) {
-		return TCL_ERROR;
+		goto error;
 	    }
+	    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
 	} else {
-	    Tcl_AppendResult(interp, "fill\n", NULL);
+	    Tcl_AppendToObj(psObj, "fill\n", -1);
 	}
-	return TCL_OK;
+	goto done;
     }
 
     /*
@@ -1896,6 +1914,7 @@ PolygonToPostscript(
      */
 
     if (fillColor != NULL && polyPtr->numPoints > 3) {
+	Tcl_ResetResult(interp);
 	if (!polyPtr->smooth || !polyPtr->smooth->postscriptProc) {
 	    Tk_CanvasPsPath(interp, canvas, polyPtr->coordPtr,
 		    polyPtr->numPoints);
@@ -1904,18 +1923,24 @@ PolygonToPostscript(
 		    polyPtr->numPoints, polyPtr->splineSteps);
 	}
 	if (Tk_CanvasPsColor(interp, canvas, fillColor) != TCL_OK) {
-	    return TCL_ERROR;
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	if (fillStipple != None) {
-	    Tcl_AppendResult(interp, "eoclip ", NULL);
+	    Tcl_AppendToObj(psObj, "eoclip ", -1);
+
+	    Tcl_ResetResult(interp);
 	    if (Tk_CanvasPsStipple(interp, canvas, fillStipple) != TCL_OK) {
-		return TCL_ERROR;
+		goto error;
 	    }
+	    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	    if (color != NULL) {
-		Tcl_AppendResult(interp, "grestore gsave\n", NULL);
+		Tcl_AppendToObj(psObj, "grestore gsave\n", -1);
 	    }
 	} else {
-	    Tcl_AppendResult(interp, "eofill\n", NULL);
+	    Tcl_AppendToObj(psObj, "eofill\n", -1);
 	}
     }
 
@@ -1924,6 +1949,7 @@ PolygonToPostscript(
      */
 
     if (color != NULL) {
+	Tcl_ResetResult(interp);
 	if (!polyPtr->smooth || !polyPtr->smooth->postscriptProc) {
 	    Tk_CanvasPsPath(interp, canvas, polyPtr->coordPtr,
 		    polyPtr->numPoints);
@@ -1931,20 +1957,38 @@ PolygonToPostscript(
 	    polyPtr->smooth->postscriptProc(interp, canvas, polyPtr->coordPtr,
 		    polyPtr->numPoints, polyPtr->splineSteps);
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
 
 	if (polyPtr->joinStyle == JoinRound) {
-	    style = "1";
+	    style = 1;
 	} else if (polyPtr->joinStyle == JoinBevel) {
-	    style = "2";
+	    style = 2;
 	} else {
-	    style = "0";
+	    style = 0;
 	}
-	Tcl_AppendResult(interp, style, " setlinejoin 1 setlinecap\n", NULL);
+	Tcl_AppendPrintfToObj(psObj, "%d setlinejoin 1 setlinecap\n", style);
+
+	Tcl_ResetResult(interp);
 	if (Tk_CanvasPsOutline(canvas, itemPtr, &polyPtr->outline) != TCL_OK){
-	    return TCL_ERROR;
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
     }
+
+    /*
+     * Plug the accumulated postscript back into the result.
+     */
+
+  done:
+    (void) Tcl_RestoreInterpState(interp, interpState);
+    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    Tcl_DecrRefCount(psObj);
     return TCL_OK;
+
+  error:
+    Tcl_DiscardInterpState(interpState);
+    Tcl_DecrRefCount(psObj);
+    return TCL_ERROR;
 }
 
 /*
diff --git a/generic/tkCanvPs.c b/generic/tkCanvPs.c
index eafc07f..6542864 100644
--- a/generic/tkCanvPs.c
+++ b/generic/tkCanvPs.c
@@ -134,6 +134,10 @@ static const Tk_ConfigSpec configSpecs[] = {
 
 static int		GetPostscriptPoints(Tcl_Interp *interp,
 			    char *string, double *doublePtr);
+static void		PostscriptBitmap(Tk_Window tkwin, Pixmap bitmap,
+			    int startX, int startY, int width, int height,
+			    Tcl_Obj *psObj);
+static inline Tcl_Obj *	GetPostscriptBuffer(Tcl_Interp *interp);
 
 /*
  *--------------------------------------------------------------
@@ -166,9 +170,9 @@ TkCanvPostscriptCmd(
     TkPostscriptInfo psInfo, *psInfoPtr = &psInfo;
     Tk_PostscriptInfo oldInfoPtr;
     int result;
+    int written;
     Tk_Item *itemPtr;
 #define STRING_LENGTH 400
-    char string[STRING_LENGTH+1];
     const char *p;
     time_t now;
     size_t length;
@@ -177,6 +181,7 @@ TkCanvPostscriptCmd(
     Tcl_HashEntry *hPtr;
     Tcl_DString buffer;
     Tcl_Obj *preambleObj;
+    Tcl_Obj *psObj;
     int deltaX = 0, deltaY = 0;	/* Offset of lower-left corner of area to be
 				 * marked up, measured in canvas units from
 				 * the positioning point on the page (reflects
@@ -200,6 +205,7 @@ TkCanvPostscriptCmd(
     }
     Tcl_IncrRefCount(preambleObj);
     Tcl_ResetResult(interp);
+    psObj = Tcl_NewObj();
 
     /*
      * Initialize the data structure describing Postscript generation, then
@@ -321,8 +327,11 @@ TkCanvPostscriptCmd(
 	} else if (strncmp(psInfo.colorMode, "color", length) == 0) {
 	    psInfo.colorLevel = 2;
 	} else {
-	    Tcl_AppendResult(interp, "bad color mode \"", psInfo.colorMode,
-		    "\": must be monochrome, gray, or color", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad color mode \"%s\": must be monochrome, gray, or color",
+		    psInfo.colorMode));
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "COLORMODE", NULL);
+	    result = TCL_ERROR;
 	    goto cleanup;
 	}
     }
@@ -333,8 +342,9 @@ TkCanvPostscriptCmd(
 	 */
 
 	if (psInfo.channelName != NULL) {
-	    Tcl_AppendResult(interp, "can't specify both -file",
-		    " and -channel", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't specify both -file and -channel", -1));
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "USAGE", NULL);
 	    result = TCL_ERROR;
 	    goto cleanup;
 	}
@@ -345,8 +355,9 @@ TkCanvPostscriptCmd(
 	 */
 
 	if (Tcl_IsSafe(interp)) {
-	    Tcl_AppendResult(interp, "can't specify -file in a",
-		    " safe interpreter", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't specify -file in a safe interpreter", -1));
+	    Tcl_SetErrorCode(interp, "TK", "SAFE", "PS_FILE", NULL);
 	    result = TCL_ERROR;
 	    goto cleanup;
 	}
@@ -375,9 +386,11 @@ TkCanvPostscriptCmd(
 	    result = TCL_ERROR;
 	    goto cleanup;
 	}
-	if ((mode & TCL_WRITABLE) == 0) {
-	    Tcl_AppendResult(interp, "channel \"", psInfo.channelName,
-		    "\" wasn't opened for writing", NULL);
+	if (!(mode & TCL_WRITABLE)) {
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "channel \"%s\" wasn't opened for writing",
+		    psInfo.channelName));
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "UNWRITABLE",NULL);
 	    result = TCL_ERROR;
 	    goto cleanup;
 	}
@@ -422,24 +435,27 @@ TkCanvPostscriptCmd(
      */
 
     if (psInfo.prolog) {
-	Tcl_AppendResult(interp, "%!PS-Adobe-3.0 EPSF-3.0\n",
-		"%%Creator: Tk Canvas Widget\n", NULL);
+	Tcl_AppendToObj(psObj,
+		"%!PS-Adobe-3.0 EPSF-3.0\n"
+		"%%Creator: Tk Canvas Widget\n", -1);
+
 #ifdef HAVE_PW_GECOS
 	if (!Tcl_IsSafe(interp)) {
 	    struct passwd *pwPtr = getpwuid(getuid());	/* INTL: Native. */
 
-	    Tcl_AppendResult(interp, "%%For: ",
-		    (pwPtr != NULL) ? pwPtr->pw_gecos : "Unknown", "\n", NULL);
+	    Tcl_AppendPrintfToObj(psObj,
+		    "%%%%For: %s\n", (pwPtr ? pwPtr->pw_gecos : "Unknown"));
 	    endpwent();
 	}
 #endif /* HAVE_PW_GECOS */
-	Tcl_AppendResult(interp, "%%Title: Window ", Tk_PathName(tkwin), "\n",
-		NULL);
+	Tcl_AppendPrintfToObj(psObj,
+		"%%%%Title: Window %s\n", Tk_PathName(tkwin));
 	time(&now);
-	Tcl_AppendResult(interp, "%%CreationDate: ",
-		ctime(&now), NULL);		/* INTL: Native. */
+	Tcl_AppendPrintfToObj(psObj,
+		"%%%%CreationDate: %s", ctime(&now));	/* INTL: Native. */
 	if (!psInfo.rotate) {
-	    sprintf(string, "%d %d %d %d",
+	    Tcl_AppendPrintfToObj(psObj,
+		    "%%%%BoundingBox: %d %d %d %d\n",
 		    (int) (psInfo.pageX + psInfo.scale*deltaX),
 		    (int) (psInfo.pageY + psInfo.scale*deltaY),
 		    (int) (psInfo.pageX + psInfo.scale*(deltaX + psInfo.width)
@@ -447,50 +463,61 @@ TkCanvPostscriptCmd(
 		    (int) (psInfo.pageY + psInfo.scale*(deltaY + psInfo.height)
 			    + 1.0));
 	} else {
-	    sprintf(string, "%d %d %d %d",
+	    Tcl_AppendPrintfToObj(psObj,
+		    "%%%%BoundingBox: %d %d %d %d\n",
 		    (int) (psInfo.pageX - psInfo.scale*(deltaY+psInfo.height)),
 		    (int) (psInfo.pageY + psInfo.scale*deltaX),
 		    (int) (psInfo.pageX - psInfo.scale*deltaY + 1.0),
 		    (int) (psInfo.pageY + psInfo.scale*(deltaX + psInfo.width)
 			    + 1.0));
 	}
-	Tcl_AppendResult(interp, "%%BoundingBox: ", string, "\n", NULL);
-	Tcl_AppendResult(interp, "%%Pages: 1\n",
-		"%%DocumentData: Clean7Bit\n", NULL);
-	Tcl_AppendResult(interp, "%%Orientation: ",
-		psInfo.rotate ? "Landscape\n" : "Portrait\n", NULL);
-	p = "%%DocumentNeededResources: font ";
+	Tcl_AppendPrintfToObj(psObj,
+		"%%%%Pages: 1\n"
+		"%%%%DocumentData: Clean7Bit\n"
+		"%%%%Orientation: %s\n",
+		psInfo.rotate ? "Landscape" : "Portrait");
+	p = "%%%%DocumentNeededResources: font %s\n";
 	for (hPtr = Tcl_FirstHashEntry(&psInfo.fontTable, &search);
 		hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
-	    Tcl_AppendResult(interp, p,
-		    Tcl_GetHashKey(&psInfo.fontTable, hPtr), "\n", NULL);
-	    p = "%%+ font ";
+	    Tcl_AppendPrintfToObj(psObj, p,
+		    Tcl_GetHashKey(&psInfo.fontTable, hPtr));
+	    p = "%%%%+ font %s\n";
 	}
-	Tcl_AppendResult(interp, "%%EndComments\n\n", NULL);
+	Tcl_AppendToObj(psObj, "%%EndComments\n\n", -1);
 
 	/*
 	 * Insert the prolog
 	 */
 
-	Tcl_AppendResult(interp, Tcl_GetString(preambleObj), NULL);
+	Tcl_AppendObjToObj(psObj, preambleObj);
 
 	if (psInfo.chan != NULL) {
-	    Tcl_Write(psInfo.chan, Tcl_GetStringResult(interp), -1);
-	    Tcl_ResetResult(canvasPtr->interp);
+	    written = Tcl_WriteObj(psInfo.chan, psObj);
+	    if (written == -1) {
+	    channelWriteFailed:
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"problem writing postscript data to channel: %s",
+			Tcl_PosixError(interp)));
+		result = TCL_ERROR;
+		goto cleanup;
+	    }
+	    Tcl_DecrRefCount(psObj);
+	    psObj = Tcl_NewObj();
 	}
 
 	/*
 	 * Document setup:  set the color level and include fonts.
 	 */
 
-	sprintf(string, "/CL %d def\n", psInfo.colorLevel);
-	Tcl_AppendResult(interp, "%%BeginSetup\n", string, NULL);
+	Tcl_AppendPrintfToObj(psObj,
+		"%%%%BeginSetup\n/CL %d def\n", psInfo.colorLevel);
 	for (hPtr = Tcl_FirstHashEntry(&psInfo.fontTable, &search);
 		hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
-	    Tcl_AppendResult(interp, "%%IncludeResource: font ",
-		    Tcl_GetHashKey(&psInfo.fontTable, hPtr), "\n", NULL);
+	    Tcl_AppendPrintfToObj(psObj,
+		    "%%%%IncludeResource: font %s\n",
+		    (char *) Tcl_GetHashKey(&psInfo.fontTable, hPtr));
 	}
-	Tcl_AppendResult(interp, "%%EndSetup\n\n", NULL);
+	Tcl_AppendToObj(psObj, "%%EndSetup\n\n", -1);
 
 	/*
 	 * Page setup: move to page positioning point, rotate if needed, set
@@ -498,18 +525,19 @@ TkCanvPostscriptCmd(
 	 * region.
 	 */
 
-	Tcl_AppendResult(interp, "%%Page: 1 1\n", "save\n", NULL);
-	sprintf(string, "%.1f %.1f translate\n", psInfo.pageX, psInfo.pageY);
-	Tcl_AppendResult(interp, string, NULL);
+	Tcl_AppendToObj(psObj, "%%Page: 1 1\nsave\n", -1);
+	Tcl_AppendPrintfToObj(psObj,
+		"%.1f %.1f translate\n", psInfo.pageX, psInfo.pageY);
 	if (psInfo.rotate) {
-	    Tcl_AppendResult(interp, "90 rotate\n", NULL);
+	    Tcl_AppendToObj(psObj, "90 rotate\n", -1);
 	}
-	sprintf(string, "%.4g %.4g scale\n", psInfo.scale, psInfo.scale);
-	Tcl_AppendResult(interp, string, NULL);
-	sprintf(string, "%d %d translate\n", deltaX - psInfo.x, deltaY);
-	Tcl_AppendResult(interp, string, NULL);
-	sprintf(string,
-		"%d %.15g moveto %d %.15g lineto %d %.15g lineto %d %.15g",
+	Tcl_AppendPrintfToObj(psObj,
+		"%.4g %.4g scale\n", psInfo.scale, psInfo.scale);
+	Tcl_AppendPrintfToObj(psObj,
+		"%d %d translate\n", deltaX - psInfo.x, deltaY);
+	Tcl_AppendPrintfToObj(psObj,
+		"%d %.15g moveto %d %.15g lineto %d %.15g lineto %d %.15g "
+		"lineto closepath clip newpath\n",
 		psInfo.x, Tk_PostscriptY((double)psInfo.y,
 			(Tk_PostscriptInfo)psInfoPtr),
 		psInfo.x2, Tk_PostscriptY((double)psInfo.y,
@@ -518,12 +546,14 @@ TkCanvPostscriptCmd(
 			(Tk_PostscriptInfo)psInfoPtr),
 		psInfo.x, Tk_PostscriptY((double)psInfo.y2,
 			(Tk_PostscriptInfo)psInfoPtr));
-	Tcl_AppendResult(interp, string,
-		" lineto closepath clip newpath\n", NULL);
-    }
-    if (psInfo.chan != NULL) {
-	Tcl_Write(psInfo.chan, Tcl_GetStringResult(interp), -1);
-	Tcl_ResetResult(canvasPtr->interp);
+	if (psInfo.chan != NULL) {
+	    written = Tcl_WriteObj(psInfo.chan, psObj);
+	    if (written == -1) {
+		goto channelWriteFailed;
+	    }
+	    Tcl_DecrRefCount(psObj);
+	    psObj = Tcl_NewObj();
+	}
     }
 
     /*
@@ -544,21 +574,28 @@ TkCanvPostscriptCmd(
 	if (itemPtr->state == TK_STATE_HIDDEN) {
 	    continue;
 	}
-	Tcl_AppendResult(interp, "gsave\n", NULL);
+
+	Tcl_ResetResult(interp);
 	result = itemPtr->typePtr->postscriptProc(interp,
 		(Tk_Canvas) canvasPtr, itemPtr, 0);
 	if (result != TCL_OK) {
-	    char msg[64 + TCL_INTEGER_SPACE];
-
-	    sprintf(msg, "\n    (generating Postscript for item %d)",
-		    itemPtr->id);
-	    Tcl_AddErrorInfo(interp, msg);
+	    Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
+		    "\n    (generating Postscript for item %d)",
+		    itemPtr->id));
 	    goto cleanup;
 	}
-	Tcl_AppendResult(interp, "grestore\n", NULL);
+
+	Tcl_AppendToObj(psObj, "gsave\n", -1);
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+	Tcl_AppendToObj(psObj, "grestore\n", -1);
+
 	if (psInfo.chan != NULL) {
-	    Tcl_Write(psInfo.chan, Tcl_GetStringResult(interp), -1);
-	    Tcl_ResetResult(interp);
+	    written = Tcl_WriteObj(psInfo.chan, psObj);
+	    if (written == -1) {
+		goto channelWriteFailed;
+	    }
+	    Tcl_DecrRefCount(psObj);
+	    psObj = Tcl_NewObj();
 	}
     }
 
@@ -568,12 +605,23 @@ TkCanvPostscriptCmd(
      */
 
     if (psInfo.prolog) {
-	Tcl_AppendResult(interp, "restore showpage\n\n",
-		"%%Trailer\nend\n%%EOF\n", NULL);
+	Tcl_AppendToObj(psObj,
+		"restore showpage\n\n"
+		"%%Trailer\n"
+		"end\n"
+		"%%EOF\n", -1);
+
+	if (psInfo.chan != NULL) {
+	    Tcl_WriteObj(psInfo.chan, psObj);
+	    if (written == -1) {
+		goto channelWriteFailed;
+	    }
+	}
     }
-    if (psInfo.chan != NULL) {
-	Tcl_Write(psInfo.chan, Tcl_GetStringResult(interp), -1);
-	Tcl_ResetResult(canvasPtr->interp);
+
+    if (psInfo.chan == NULL) {
+	Tcl_SetObjResult(interp, psObj);
+	psObj = Tcl_NewObj();
     }
 
     /*
@@ -614,9 +662,23 @@ TkCanvPostscriptCmd(
     Tcl_DeleteHashTable(&psInfo.fontTable);
     canvasPtr->psInfo = (Tk_PostscriptInfo) oldInfoPtr;
     Tcl_DecrRefCount(preambleObj);
+    Tcl_DecrRefCount(psObj);
     return result;
 }
 
+static inline Tcl_Obj *
+GetPostscriptBuffer(
+    Tcl_Interp *interp)
+{
+    Tcl_Obj *psObj = Tcl_GetObjResult(interp);
+
+    if (Tcl_IsShared(psObj)) {
+	psObj = Tcl_DuplicateObj(psObj);
+	Tcl_SetObjResult(interp, psObj);
+    }
+    return psObj;
+}
+
 /*
  *--------------------------------------------------------------
  *
@@ -645,9 +707,7 @@ Tk_PostscriptColor(
     XColor *colorPtr)		/* Information about color. */
 {
     TkPostscriptInfo *psInfoPtr = (TkPostscriptInfo *) psInfo;
-    int tmp;
     double red, green, blue;
-    char string[200];
 
     if (psInfoPtr->prepass) {
 	return TCL_OK;
@@ -659,12 +719,12 @@ Tk_PostscriptColor(
      */
 
     if (psInfoPtr->colorVar != NULL) {
-	const char *cmdString;
-
-	cmdString = Tcl_GetVar2(interp, psInfoPtr->colorVar,
+	const char *cmdString = Tcl_GetVar2(interp, psInfoPtr->colorVar,
 		Tk_NameOfColor(colorPtr), 0);
+
 	if (cmdString != NULL) {
-	    Tcl_AppendResult(interp, cmdString, "\n", NULL);
+	    Tcl_AppendPrintfToObj(GetPostscriptBuffer(interp),
+		    "%s\n", cmdString);
 	    return TCL_OK;
 	}
     }
@@ -681,15 +741,12 @@ Tk_PostscriptColor(
      * per color, but most diplays use at least 8 bits.
      */
 
-    tmp = colorPtr->red;
-    red = ((double) (tmp >> 8))/255.0;
-    tmp = colorPtr->green;
-    green = ((double) (tmp >> 8))/255.0;
-    tmp = colorPtr->blue;
-    blue = ((double) (tmp >> 8))/255.0;
-    sprintf(string, "%.3f %.3f %.3f setrgbcolor AdjustColor\n",
+    red = ((double) (((int) colorPtr->red) >> 8))/255.0;
+    green = ((double) (((int) colorPtr->green) >> 8))/255.0;
+    blue = ((double) (((int) colorPtr->blue) >> 8))/255.0;
+    Tcl_AppendPrintfToObj(GetPostscriptBuffer(interp),
+	    "%.3f %.3f %.3f setrgbcolor AdjustColor\n",
 	    red, green, blue);
-    Tcl_AppendResult(interp, string, NULL);
     return TCL_OK;
 }
 
@@ -723,9 +780,9 @@ Tk_PostscriptFont(
 				 * be printed. */
 {
     TkPostscriptInfo *psInfoPtr = (TkPostscriptInfo *) psInfo;
-    char pointString[TCL_INTEGER_SPACE];
     Tcl_DString ds;
     int i, points;
+    const char *fontname;
 
     /*
      * First, look up the font's name in the font map, if there is one. If
@@ -741,28 +798,24 @@ Tk_PostscriptFont(
 	Tcl_Obj *list = Tcl_GetVar2Ex(interp, psInfoPtr->fontVar, name, 0);
 
 	if (list != NULL) {
-	    const char *fontname;
-
 	    if (Tcl_ListObjGetElements(interp, list, &objc, &objv) != TCL_OK
 		    || objc != 2
-		    || Tcl_GetString(objv[0])[0] == '\0'
+		    || (fontname = Tcl_GetString(objv[0]))[0] == '\0'
+		    || strchr(fontname, ' ') != NULL
 		    || Tcl_GetDoubleFromObj(interp, objv[1], &size) != TCL_OK
 		    || size <= 0) {
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "bad font map entry for \"", name,
-			"\": \"", Tcl_GetString(list), "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"bad font map entry for \"%s\": \"%s\"",
+			name, Tcl_GetString(list)));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "FONTMAP",
+			NULL);
 		return TCL_ERROR;
 	    }
 
-	    fontname = Tcl_GetString(objv[0]);
-	    sprintf(pointString, "%d", (int) size);
-
-	    Tcl_AppendResult(interp, "/", fontname, " findfont ",
-		    pointString, " scalefont ", NULL);
-	    if (strncasecmp(fontname, "Symbol", 7) != 0) {
-		Tcl_AppendResult(interp, "ISOEncode ", NULL);
-	    }
-	    Tcl_AppendResult(interp, "setfont\n", NULL);
+	    Tcl_AppendPrintfToObj(GetPostscriptBuffer(interp),
+		    "/%s findfont %d scalefont%s setfont\n",
+		    fontname, (int) size,
+		    strncasecmp(fontname, "Symbol", 7) ? " ISOEncode" : "");
 	    Tcl_CreateHashEntry(&psInfoPtr->fontTable, fontname, &i);
 	    return TCL_OK;
 	}
@@ -774,13 +827,11 @@ Tk_PostscriptFont(
 
     Tcl_DStringInit(&ds);
     points = Tk_PostscriptFontName(tkfont, &ds);
-    sprintf(pointString, "%d", TkFontGetPoints(psInfoPtr->tkwin, points));
-    Tcl_AppendResult(interp, "/", Tcl_DStringValue(&ds), " findfont ",
-	    pointString, " scalefont ", NULL);
-    if (strncasecmp(Tcl_DStringValue(&ds), "Symbol", 7) != 0) {
-	Tcl_AppendResult(interp, "ISOEncode ", NULL);
-    }
-    Tcl_AppendResult(interp, "setfont\n", NULL);
+    fontname = Tcl_DStringValue(&ds);
+    Tcl_AppendPrintfToObj(GetPostscriptBuffer(interp),
+	    "/%s findfont %d scalefont%s setfont\n",
+	    fontname, TkFontGetPoints(psInfoPtr->tkwin, points),
+	    strncasecmp(fontname, "Symbol", 7) ? " ISOEncode" : "");
     Tcl_CreateHashEntry(&psInfoPtr->fontTable, Tcl_DStringValue(&ds), &i);
     Tcl_DStringFree(&ds);
 
@@ -818,18 +869,32 @@ Tk_PostscriptBitmap(
     int width, int height)	/* Height of rectangular region. */
 {
     TkPostscriptInfo *psInfoPtr = (TkPostscriptInfo *) psInfo;
+
+    if (psInfoPtr->prepass) {
+	return TCL_OK;
+    }
+
+    PostscriptBitmap(tkwin, bitmap, startX, startY, width, height,
+	    GetPostscriptBuffer(interp));
+    return TCL_OK;
+}
+
+static void
+PostscriptBitmap(
+    Tk_Window tkwin,
+    Pixmap bitmap,		/* Bitmap for which to generate Postscript. */
+    int startX, int startY,	/* Coordinates of upper-left corner of
+				 * rectangular region to output. */
+    int width, int height,	/* Height of rectangular region. */
+    Tcl_Obj *psObj)		/* Where to append the postscript. */
+{
     XImage *imagePtr;
     int charsInLine, x, y, lastX, lastY, value, mask;
     unsigned int totalWidth, totalHeight;
-    char string[100];
     Window dummyRoot;
     int dummyX, dummyY;
     unsigned dummyBorderwidth, dummyDepth;
 
-    if (psInfoPtr->prepass) {
-	return TCL_OK;
-    }
-
     /*
      * The following call should probably be a call to Tk_SizeOfBitmap
      * instead, but it seems that we are occasionally invoked by custom item
@@ -843,7 +908,8 @@ Tk_PostscriptBitmap(
 	    (unsigned int *) &totalHeight, &dummyBorderwidth, &dummyDepth);
     imagePtr = XGetImage(Tk_Display(tkwin), bitmap, 0, 0,
 	    totalWidth, totalHeight, 1, XYPixmap);
-    Tcl_AppendResult(interp, "<", NULL);
+
+    Tcl_AppendToObj(psObj, "<", -1);
     mask = 0x80;
     value = 0;
     charsInLine = 0;
@@ -856,28 +922,26 @@ Tk_PostscriptBitmap(
 	    }
 	    mask >>= 1;
 	    if (mask == 0) {
-		sprintf(string, "%02x", value);
-		Tcl_AppendResult(interp, string, NULL);
+		Tcl_AppendPrintfToObj(psObj, "%02x", value);
 		mask = 0x80;
 		value = 0;
 		charsInLine += 2;
 		if (charsInLine >= 60) {
-		    Tcl_AppendResult(interp, "\n", NULL);
+		    Tcl_AppendToObj(psObj, "\n", -1);
 		    charsInLine = 0;
 		}
 	    }
 	}
 	if (mask != 0x80) {
-	    sprintf(string, "%02x", value);
-	    Tcl_AppendResult(interp, string, NULL);
+	    Tcl_AppendPrintfToObj(psObj, "%02x", value);
 	    mask = 0x80;
 	    value = 0;
 	    charsInLine += 2;
 	}
     }
-    Tcl_AppendResult(interp, ">", NULL);
+    Tcl_AppendToObj(psObj, ">", -1);
+
     XDestroyImage(imagePtr);
-    return TCL_OK;
 }
 
 /*
@@ -912,10 +976,10 @@ Tk_PostscriptStipple(
 {
     TkPostscriptInfo *psInfoPtr = (TkPostscriptInfo *) psInfo;
     int width, height;
-    char string[TCL_INTEGER_SPACE * 2];
     Window dummyRoot;
     int dummyX, dummyY;
     unsigned dummyBorderwidth, dummyDepth;
+    Tcl_Obj *psObj;
 
     if (psInfoPtr->prepass) {
 	return TCL_OK;
@@ -932,13 +996,11 @@ Tk_PostscriptStipple(
     XGetGeometry(Tk_Display(tkwin), bitmap, &dummyRoot,
 	    (int *) &dummyX, (int *) &dummyY, (unsigned *) &width,
 	    (unsigned *) &height, &dummyBorderwidth, &dummyDepth);
-    sprintf(string, "%d %d ", width, height);
-    Tcl_AppendResult(interp, string, NULL);
-    if (Tk_PostscriptBitmap(interp, tkwin, psInfo, bitmap, 0, 0,
-	    width, height) != TCL_OK) {
-	return TCL_ERROR;
-    }
-    Tcl_AppendResult(interp, " StippleFill\n", NULL);
+
+    psObj = GetPostscriptBuffer(interp);
+    Tcl_AppendPrintfToObj(psObj, "%d %d ", width, height);
+    PostscriptBitmap(tkwin, bitmap, 0, 0, width, height, psObj);
+    Tcl_AppendToObj(psObj, " StippleFill\n", -1);
     return TCL_OK;
 }
 
@@ -998,19 +1060,19 @@ Tk_PostscriptPath(
     int numPoints)		/* Number of points at *coordPtr. */
 {
     TkPostscriptInfo *psInfoPtr = (TkPostscriptInfo *) psInfo;
-    char buffer[200];
+    Tcl_Obj *psObj;
 
     if (psInfoPtr->prepass) {
 	return;
     }
-    sprintf(buffer, "%.15g %.15g moveto\n", coordPtr[0],
-	    Tk_PostscriptY(coordPtr[1], psInfo));
-    Tcl_AppendResult(interp, buffer, NULL);
+
+    psObj = GetPostscriptBuffer(interp);
+    Tcl_AppendPrintfToObj(psObj, "%.15g %.15g moveto\n",
+	    coordPtr[0], Tk_PostscriptY(coordPtr[1], psInfo));
     for (numPoints--, coordPtr += 2; numPoints > 0;
 	    numPoints--, coordPtr += 2) {
-	sprintf(buffer, "%.15g %.15g lineto\n", coordPtr[0],
-		Tk_PostscriptY(coordPtr[1], psInfo));
-	Tcl_AppendResult(interp, buffer, NULL);
+	Tcl_AppendPrintfToObj(psObj, "%.15g %.15g lineto\n",
+		coordPtr[0], Tk_PostscriptY(coordPtr[1], psInfo));
     }
 }
 
@@ -1081,7 +1143,8 @@ GetPostscriptPoints(
     return TCL_OK;
 
   error:
-    Tcl_AppendResult(interp, "bad distance \"", string, "\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf("bad distance \"%s\"", string));
+    Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "POINTS", NULL);
     return TCL_ERROR;
 }
 
@@ -1195,15 +1258,15 @@ TkPostscriptImage(
     int width, int height)	/* Width and height of area */
 {
     TkPostscriptInfo *psInfoPtr = (TkPostscriptInfo *) psInfo;
-    char buffer[256];
     int xx, yy, band, maxRows;
     double red, green, blue;
-    int bytesPerLine=0, maxWidth=0;
+    int bytesPerLine = 0, maxWidth = 0;
     int level = psInfoPtr->colorLevel;
     Colormap cmap;
     int i, ncolors;
     Visual *visual;
     TkColormapData cdata;
+    Tcl_Obj *psObj;
 
     if (psInfoPtr->prepass) {
 	return TCL_OK;
@@ -1289,15 +1352,16 @@ TkPostscriptImage(
 
     if (bytesPerLine > 60000) {
 	Tcl_ResetResult(interp);
-	sprintf(buffer,
-		"Can't generate Postscript for images more than %d pixels wide",
-		maxWidth);
-	Tcl_AppendResult(interp, buffer, NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't generate Postscript for images more than %d pixels wide",
+		maxWidth));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "MEMLIMIT", NULL);
 	ckfree(cdata.colors);
 	return TCL_ERROR;
     }
 
     maxRows = 60000 / bytesPerLine;
+    psObj = GetPostscriptBuffer(interp);
 
     for (band = height-1; band >= 0; band -= maxRows) {
 	int rows = (band >= maxRows) ? maxRows : band + 1;
@@ -1305,16 +1369,13 @@ TkPostscriptImage(
 
 	switch (level) {
 	case 0:
-	    sprintf(buffer, "%d %d 1 matrix {\n<", width, rows);
-	    Tcl_AppendResult(interp, buffer, NULL);
+	    Tcl_AppendPrintfToObj(psObj, "%d %d 1 matrix {\n<", width, rows);
 	    break;
 	case 1:
-	    sprintf(buffer, "%d %d 8 matrix {\n<", width, rows);
-	    Tcl_AppendResult(interp, buffer, NULL);
+	    Tcl_AppendPrintfToObj(psObj, "%d %d 8 matrix {\n<", width, rows);
 	    break;
 	default:
-	    sprintf(buffer, "%d %d 8 matrix {\n<", width, rows);
-	    Tcl_AppendResult(interp, buffer, NULL);
+	    Tcl_AppendPrintfToObj(psObj, "%d %d 8 matrix {\n<", width, rows);
 	    break;
 	}
 	for (yy = band; yy > band - rows; yy--) {
@@ -1336,22 +1397,20 @@ TkPostscriptImage(
 		    }
 		    mask >>= 1;
 		    if (mask == 0) {
-			sprintf(buffer, "%02X", data);
-			Tcl_AppendResult(interp, buffer, NULL);
+			Tcl_AppendPrintfToObj(psObj, "%02X", data);
 			lineLen += 2;
 			if (lineLen > 60) {
 			    lineLen = 0;
-			    Tcl_AppendResult(interp, "\n", NULL);
+			    Tcl_AppendToObj(psObj, "\n", -1);
 			}
-			mask=0x80;
-			data=0x00;
+			mask = 0x80;
+			data = 0x00;
 		    }
 		}
 		if ((width % 8) != 0) {
-		    sprintf(buffer, "%02X", data);
-		    Tcl_AppendResult(interp, buffer, NULL);
-		    mask=0x80;
-		    data=0x00;
+		    Tcl_AppendPrintfToObj(psObj, "%02X", data);
+		    mask = 0x80;
+		    data = 0x00;
 		}
 		break;
 	    }
@@ -1364,13 +1423,13 @@ TkPostscriptImage(
 		for (xx = x; xx < x+width; xx ++) {
 		    TkImageGetColor(&cdata, XGetPixel(ximage, xx, yy),
 			    &red, &green, &blue);
-		    sprintf(buffer, "%02X", (int) floor(0.5 + 255.0 *
+		    Tcl_AppendPrintfToObj(psObj, "%02X",
+			    (int) floor(0.5 + 255.0 *
 			    (0.30 * red + 0.59 * green + 0.11 * blue)));
-		    Tcl_AppendResult(interp, buffer, NULL);
 		    lineLen += 2;
 		    if (lineLen > 60) {
 			lineLen = 0;
-			Tcl_AppendResult(interp, "\n", NULL);
+			Tcl_AppendToObj(psObj, "\n", -1);
 		    }
 		}
 		break;
@@ -1383,15 +1442,14 @@ TkPostscriptImage(
 		for (xx = x; xx < x+width; xx++) {
 		    TkImageGetColor(&cdata, XGetPixel(ximage, xx, yy),
 			    &red, &green, &blue);
-		    sprintf(buffer, "%02X%02X%02X",
+		    Tcl_AppendPrintfToObj(psObj, "%02X%02X%02X",
 			    (int) floor(0.5 + 255.0 * red),
 			    (int) floor(0.5 + 255.0 * green),
 			    (int) floor(0.5 + 255.0 * blue));
-		    Tcl_AppendResult(interp, buffer, NULL);
 		    lineLen += 6;
 		    if (lineLen > 60) {
 			lineLen = 0;
-			Tcl_AppendResult(interp, "\n", NULL);
+			Tcl_AppendToObj(psObj, "\n", -1);
 		    }
 		}
 		break;
@@ -1399,13 +1457,11 @@ TkPostscriptImage(
 	}
 	switch (level) {
 	case 0: case 1:
-	    sprintf(buffer, ">\n} image\n"); break;
+	    Tcl_AppendToObj(psObj, ">\n} image\n", -1); break;
 	default:
-	    sprintf(buffer, ">\n} false 3 colorimage\n"); break;
+	    Tcl_AppendToObj(psObj, ">\n} false 3 colorimage\n", -1); break;
 	}
-	Tcl_AppendResult(interp, buffer, NULL);
-	sprintf(buffer, "0 %d translate\n", rows);
-	Tcl_AppendResult(interp, buffer, NULL);
+	Tcl_AppendPrintfToObj(psObj, "0 %d translate\n", rows);
     }
     ckfree(cdata.colors);
     return TCL_OK;
@@ -1441,15 +1497,15 @@ Tk_PostscriptPhoto(
 {
     TkPostscriptInfo *psInfoPtr = (TkPostscriptInfo *) psInfo;
     int colorLevel = psInfoPtr->colorLevel;
-    const char *displayOperation;
+    const char *displayOperation, *decode;
     unsigned char *pixelPtr;
-    char buffer[256], cspace[40], decode[40];
     int bpc, xx, yy, lineLen, alpha;
     float red, green, blue;
-    int bytesPerLine=0, maxWidth=0;
+    int bytesPerLine = 0, maxWidth = 0;
     unsigned char opaque = 255;
     unsigned char *alphaPtr;
     int alphaOffset, alphaPitch, alphaIncr;
+    Tcl_Obj *psObj;
 
     if (psInfoPtr->prepass) {
 	return TCL_OK;
@@ -1482,10 +1538,10 @@ Tk_PostscriptPhoto(
     }
     if (bytesPerLine > 60000) {
 	Tcl_ResetResult(interp);
-	sprintf(buffer,
-		"Can't generate Postscript for images more than %d pixels wide",
-		maxWidth);
-	Tcl_AppendResult(interp, buffer, NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't generate Postscript for images more than %d pixels wide",
+		maxWidth));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "MEMLIMIT", NULL);
 	return TCL_ERROR;
     }
 
@@ -1493,35 +1549,32 @@ Tk_PostscriptPhoto(
      * Set up the postscript code except for the image-data stream.
      */
 
+    psObj = GetPostscriptBuffer(interp);
     switch (colorLevel) {
     case 0:
-	strcpy(cspace, "/DeviceGray");
-	strcpy(decode, "[1 0]");
+	Tcl_AppendToObj(psObj, "/DeviceGray setcolorspace\n\n", -1);
+	decode = "1 0";
 	bpc = 1;
 	break;
     case 1:
-	strcpy(cspace, "/DeviceGray");
-	strcpy(decode, "[0 1]");
+	Tcl_AppendToObj(psObj, "/DeviceGray setcolorspace\n\n", -1);
+	decode = "0 1";
 	bpc = 8;
 	break;
     default:
-	strcpy(cspace, "/DeviceRGB");
-	strcpy(decode, "[0 1 0 1 0 1]");
+	Tcl_AppendToObj(psObj, "/DeviceRGB setcolorspace\n\n", -1);
+	decode = "0 1 0 1 0 1";
 	bpc = 8;
 	break;
     }
 
-
-    Tcl_AppendResult(interp, cspace, " setcolorspace\n\n", NULL);
-
-    sprintf(buffer, "  /Width %d\n  /Height %d\n  /BitsPerComponent %d\n",
-	    width, height,  bpc);
-    Tcl_AppendResult(interp, "<<\n  /ImageType 1\n", buffer,
-	    "  /DataSource currentfile  /ASCIIHexDecode filter\n", NULL);
-
-    sprintf(buffer, "  /ImageMatrix [1 0 0 -1 0 %d]\n", height);
-    Tcl_AppendResult(interp, buffer, "  /Decode ", decode, "\n>>\n1 ",
-	    displayOperation, "\n", NULL);
+    Tcl_AppendPrintfToObj(psObj,
+	    "<<\n  /ImageType 1\n"
+	    "  /Width %d\n  /Height %d\n  /BitsPerComponent %d\n"
+	    "  /DataSource currentfile\n  /ASCIIHexDecode filter\n"
+	    "  /ImageMatrix [1 0 0 -1 0 %d]\n  /Decode [%s]\n>>\n"
+	    "1 %s\n",
+	    width, height, bpc, height, decode, displayOperation);
 
     /*
      * Check the PhotoImageBlock information. We assume that:
@@ -1581,20 +1634,18 @@ Tk_PostscriptPhoto(
 		}
 		mask >>= 1;
 		if (mask == 0) {
-		    sprintf(buffer, "%02X", data);
-		    Tcl_AppendResult(interp, buffer, NULL);
+		    Tcl_AppendPrintfToObj(psObj, "%02X", data);
 		    lineLen += 2;
 		    if (lineLen >= 60) {
 			lineLen = 0;
-			Tcl_AppendResult(interp, "\n", NULL);
+			Tcl_AppendToObj(psObj, "\n", -1);
 		    }
 		    mask = 0x80;
 		    data = 0x00;
 		}
 	    }
 	    if ((width % 8) != 0) {
-		sprintf(buffer, "%02X", data);
-		Tcl_AppendResult(interp, buffer, NULL);
+		Tcl_AppendPrintfToObj(psObj, "%02X", data);
 		mask = 0x80;
 		data = 0x00;
 	    }
@@ -1622,20 +1673,18 @@ Tk_PostscriptPhoto(
 		}
 		mask >>= 1;
 		if (mask == 0) {
-		    sprintf(buffer, "%02X", data);
-		    Tcl_AppendResult(interp, buffer, NULL);
+		    Tcl_AppendPrintfToObj(psObj, "%02X", data);
 		    lineLen += 2;
 		    if (lineLen >= 60) {
 			lineLen = 0;
-			Tcl_AppendResult(interp, "\n", NULL);
+			Tcl_AppendToObj(psObj, "\n", -1);
 		    }
 		    mask = 0x80;
 		    data = 0x00;
 		}
 	    }
 	    if ((width % 8) != 0) {
-		sprintf(buffer, "%02X", data);
-		Tcl_AppendResult(interp, buffer, NULL);
+		Tcl_AppendPrintfToObj(psObj, "%02X", data);
 		mask = 0x80;
 		data = 0x00;
 	    }
@@ -1650,12 +1699,11 @@ Tk_PostscriptPhoto(
 	    for (xx = 0; xx < width; xx ++) {
 		alpha = *(alphaPtr + (yy * alphaPitch)
 			+ (xx * alphaIncr) + alphaOffset);
-		sprintf(buffer, "%02X", alpha | 0x01);
-		Tcl_AppendResult(interp, buffer, NULL);
+		Tcl_AppendPrintfToObj(psObj, "%02X", alpha | 0x01);
 		lineLen += 2;
 		if (lineLen >= 60) {
 		    lineLen = 0;
-		    Tcl_AppendResult(interp, "\n", NULL);
+		    Tcl_AppendToObj(psObj, "\n", -1);
 		}
 	    }
 
@@ -1672,13 +1720,12 @@ Tk_PostscriptPhoto(
 		green = pixelPtr[blockPtr->offset[1]];
 		blue = pixelPtr[blockPtr->offset[2]];
 
-		sprintf(buffer, "%02X", (int) floor(0.5 +
+		Tcl_AppendPrintfToObj(psObj, "%02X", (int) floor(0.5 +
 			( 0.3086 * red + 0.6094 * green + 0.0820 * blue)));
-		Tcl_AppendResult(interp, buffer, NULL);
 		lineLen += 2;
 		if (lineLen >= 60) {
 		    lineLen = 0;
-		    Tcl_AppendResult(interp, "\n", NULL);
+		    Tcl_AppendToObj(psObj, "\n", -1);
 		}
 	    }
 	    break;
@@ -1692,12 +1739,11 @@ Tk_PostscriptPhoto(
 	    for (xx = 0; xx < width; xx ++) {
 		alpha = *(alphaPtr + (yy * alphaPitch)
 			+ (xx * alphaIncr) + alphaOffset);
-		sprintf(buffer, "%02X", alpha | 0x01);
-		Tcl_AppendResult(interp, buffer, NULL);
+		Tcl_AppendPrintfToObj(psObj, "%02X", alpha | 0x01);
 		lineLen += 2;
 		if (lineLen >= 60) {
 		    lineLen = 0;
-		    Tcl_AppendResult(interp, "\n", NULL);
+		    Tcl_AppendToObj(psObj, "\n", -1);
 		}
 	    }
 
@@ -1710,22 +1756,25 @@ Tk_PostscriptPhoto(
 		pixelPtr = blockPtr->pixelPtr + (yy * blockPtr->pitch)
 			+ (xx * blockPtr->pixelSize);
 
-		sprintf(buffer, "%02X%02X%02X",
+		Tcl_AppendPrintfToObj(psObj, "%02X%02X%02X",
 			pixelPtr[blockPtr->offset[0]],
 			pixelPtr[blockPtr->offset[1]],
 			pixelPtr[blockPtr->offset[2]]);
-		Tcl_AppendResult(interp, buffer, NULL);
 		lineLen += 6;
 		if (lineLen >= 60) {
 		    lineLen = 0;
-		    Tcl_AppendResult(interp, "\n", NULL);
+		    Tcl_AppendToObj(psObj, "\n", -1);
 		}
 	    }
 	    break;
 	}
     }
 
-    Tcl_AppendResult(interp, ">\n", NULL);
+    /*
+     * The end-of-data marker.
+     */
+
+    Tcl_AppendToObj(psObj, ">\n", -1);
     return TCL_OK;
 }
 
diff --git a/generic/tkCanvText.c b/generic/tkCanvText.c
index 0861a21..eb8dfe3 100644
--- a/generic/tkCanvText.c
+++ b/generic/tkCanvText.c
@@ -338,29 +338,32 @@ TextCoords(
 	subobj = Tcl_NewDoubleObj(textPtr->y);
 	Tcl_ListObjAppendElement(interp, obj, subobj);
 	Tcl_SetObjResult(interp, obj);
-    } else if (objc < 3) {
-	if (objc == 1) {
-	    if (Tcl_ListObjGetElements(interp, objv[0], &objc,
-		    (Tcl_Obj ***) &objv) != TCL_OK) {
-		return TCL_ERROR;
-	    } else if (objc != 2) {
-		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
-			"wrong # coordinates: expected 2, got %d", objc));
-		return TCL_ERROR;
-	    }
-	}
-	if ((Tk_CanvasGetCoordFromObj(interp, canvas, objv[0],
-		    &textPtr->x) != TCL_OK)
-		|| (Tk_CanvasGetCoordFromObj(interp, canvas, objv[1],
-		    &textPtr->y) != TCL_OK)) {
-	    return TCL_ERROR;
-	}
-	ComputeTextBbox(canvas, textPtr);
-    } else {
+	return TCL_OK;
+    } else if (objc > 2) {
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"wrong # coordinates: expected 0 or 2, got %d", objc));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "TEXT", NULL);
+	return TCL_ERROR;
+    }
+
+    if (objc == 1) {
+	if (Tcl_ListObjGetElements(interp, objv[0], &objc,
+		(Tcl_Obj ***) &objv) != TCL_OK) {
+	    return TCL_ERROR;
+	} else if (objc != 2) {
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # coordinates: expected 2, got %d", objc));
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "TEXT", NULL);
+	    return TCL_ERROR;
+	}
+    }
+    if ((Tk_CanvasGetCoordFromObj(interp, canvas, objv[0],
+		&textPtr->x) != TCL_OK)
+	    || (Tk_CanvasGetCoordFromObj(interp, canvas, objv[1],
+		&textPtr->y) != TCL_OK)) {
 	return TCL_ERROR;
     }
+    ComputeTextBbox(canvas, textPtr);
     return TCL_OK;
 }
 
@@ -1356,14 +1359,18 @@ GetTextIndex(
     } else if ((c == 's') && (length >= 5)
 	    && (strncmp(string, "sel.first", (unsigned) length) == 0)) {
 	if (textInfoPtr->selItemPtr != itemPtr) {
-	    Tcl_SetResult(interp, "selection isn't in item", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "selection isn't in item", -1));
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "UNSELECTED", NULL);
 	    return TCL_ERROR;
 	}
 	*indexPtr = textInfoPtr->selectFirst;
     } else if ((c == 's') && (length >= 5)
 	    && (strncmp(string, "sel.last", (unsigned) length) == 0)) {
 	if (textInfoPtr->selItemPtr != itemPtr) {
-	    Tcl_SetResult(interp, "selection isn't in item", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "selection isn't in item", -1));
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "UNSELECTED", NULL);
 	    return TCL_ERROR;
 	}
 	*indexPtr = textInfoPtr->selectLast;
@@ -1403,6 +1410,7 @@ GetTextIndex(
 
     badIndex:
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf("bad index \"%s\"", string));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "ITEM_INDEX", "TEXT", NULL);
 	return TCL_ERROR;
     }
     return TCL_OK;
@@ -1536,6 +1544,8 @@ TextToPostscript(
     XColor *color;
     Pixmap stipple;
     Tk_State state = itemPtr->state;
+    Tcl_Obj *psObj;
+    Tcl_InterpState interpState;
 
     if (state == TK_STATE_NULL) {
 	state = Canvas(canvas)->canvas_state;
@@ -1561,26 +1571,40 @@ TextToPostscript(
 	}
     }
 
+    /*
+     * Make our working space.
+     */
+
+    psObj = Tcl_NewObj();
+    interpState = Tcl_SaveInterpState(interp, TCL_OK);
+
+    /*
+     * Generate postscript.
+     */
+
+    Tcl_ResetResult(interp);
     if (Tk_CanvasPsFont(interp, canvas, textPtr->tkfont) != TCL_OK) {
-	return TCL_ERROR;
+	goto error;
     }
+    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
     if (prepass != 0) {
-	return TCL_OK;
+	goto done;
     }
+
+    Tcl_ResetResult(interp);
     if (Tk_CanvasPsColor(interp, canvas, color) != TCL_OK) {
-	return TCL_ERROR;
+	goto error;
     }
+    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
     if (stipple != None) {
-	Tcl_AppendResult(interp, "/StippleText {\n    ", NULL);
+	Tcl_ResetResult(interp);
 	Tk_CanvasPsStipple(interp, canvas, stipple);
-	Tcl_AppendResult(interp, "} bind def\n", NULL);
+	Tcl_AppendPrintfToObj(psObj, "/StippleText {\n    %s} bind def\n",
+		Tcl_GetString(Tcl_GetObjResult(interp)));
     }
 
-    Tcl_AppendPrintfToObj(Tcl_GetObjResult(interp), "%.15g %.15g %.15g [\n",
-	    textPtr->angle, textPtr->x, Tk_CanvasPsY(canvas, textPtr->y));
-
-    Tk_TextLayoutToPostscript(interp, textPtr->textLayout);
-
     x = 0;  y = 0;  justify = NULL;	/* lint. */
     switch (textPtr->anchor) {
     case TK_ANCHOR_NW:	   x = 0; y = 0; break;
@@ -1600,12 +1624,31 @@ TextToPostscript(
     }
 
     Tk_GetFontMetrics(textPtr->tkfont, &fm);
-    Tcl_AppendPrintfToObj(Tcl_GetObjResult(interp),
+
+    Tcl_AppendPrintfToObj(psObj, "%.15g %.15g %.15g [\n",
+	    textPtr->angle, textPtr->x, Tk_CanvasPsY(canvas, textPtr->y));
+    Tcl_ResetResult(interp);
+    Tk_TextLayoutToPostscript(interp, textPtr->textLayout);
+    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+    Tcl_AppendPrintfToObj(psObj,
 	    "] %d %g %g %s %s DrawText\n",
 	    fm.linespace, x / -2.0, y / 2.0, justify,
 	    ((stipple == None) ? "false" : "true"));
 
+    /*
+     * Plug the accumulated postscript back into the result.
+     */
+
+  done:
+    (void) Tcl_RestoreInterpState(interp, interpState);
+    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    Tcl_DecrRefCount(psObj);
     return TCL_OK;
+
+  error:
+    Tcl_DiscardInterpState(interpState);
+    Tcl_DecrRefCount(psObj);
+    return TCL_ERROR;
 }
 
 /*
diff --git a/generic/tkCanvUtil.c b/generic/tkCanvUtil.c
index 1a6a8c4..23c73e5 100644
--- a/generic/tkCanvUtil.c
+++ b/generic/tkCanvUtil.c
@@ -49,9 +49,23 @@ static int		DashConvert(char *l, const char *p, int n,
 			    double width);
 static void		TranslateAndAppendCoords(TkCanvas *canvPtr,
 			    double x, double y, XPoint *outArr, int numOut);
+static inline Tcl_Obj *	GetPostscriptBuffer(Tcl_Interp *interp);
 
 #define ABS(a) ((a>=0)?(a):(-(a)))
 
+static inline Tcl_Obj *
+GetPostscriptBuffer(
+    Tcl_Interp *interp)
+{
+    Tcl_Obj *psObj = Tcl_GetObjResult(interp);
+
+    if (Tcl_IsShared(psObj)) {
+	psObj = Tcl_DuplicateObj(psObj);
+	Tcl_SetObjResult(interp, psObj);
+    }
+    return psObj;
+}
+
 /*
  *----------------------------------------------------------------------
  *
@@ -756,8 +770,10 @@ TkSmoothParseProc(
     while (methods != NULL) {
 	if (strncmp(value, methods->smooth.name, length) == 0) {
 	    if (smooth != NULL) {
-		Tcl_AppendResult(interp, "ambiguous smooth method \"", value,
-			"\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"ambiguous smooth method \"%s\"", value));
+		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "SMOOTH", value,
+			NULL);
 		return TCL_ERROR;
 	    }
 	    smooth = &methods->smooth;
@@ -878,7 +894,7 @@ Tk_GetDash(
     if ((unsigned) ABS(dash->number) > sizeof(char *)) {
 	ckfree(dash->pattern.pt);
     }
-    if (argc > (int)sizeof(char *)) {
+    if (argc > (int) sizeof(char *)) {
 	dash->pattern.pt = pt = ckalloc(argc);
     } else {
 	pt = dash->pattern.array;
@@ -886,12 +902,12 @@ Tk_GetDash(
     dash->number = argc;
 
     largv = argv;
-    while (argc>0) {
+    while (argc > 0) {
 	if (Tcl_GetInt(interp, *largv, &i) != TCL_OK || i < 1 || i>255) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp,
-		    "expected integer in the range 1..255 but got \"",
-		    *largv, "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "expected integer in the range 1..255 but got \"%s\"",
+		    *largv));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "DASH", NULL);
 	    goto syntaxError;
 	}
 	*pt++ = i;
@@ -909,8 +925,10 @@ Tk_GetDash(
      */
 
   badDashList:
-    Tcl_AppendResult(interp, "bad dash list \"", value,
-	    "\": must be a list of integers or a format like \"-..\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad dash list \"%s\": must be a list of integers or a format like \"-..\"",
+	    value));
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "DASH", NULL);
   syntaxError:
     if (argv != NULL) {
 	ckfree(argv);
@@ -1252,9 +1270,9 @@ Tk_ChangeOutlineGC(
  *
  * Tk_ResetOutlineGC
  *
- *	Restores the GC to the situation before Tk_ChangeOutlineGC() was called.
- *	This function should be called just after the dashed item is drawn,
- *	because the GC is supposed to be read-only.
+ *	Restores the GC to the situation before Tk_ChangeOutlineGC() was
+ *	called. This function should be called just after the dashed item is
+ *	drawn, because the GC is supposed to be read-only.
  *
  * Results:
  *	1 if there is a stipple pattern, and 0 otherwise.
@@ -1361,15 +1379,16 @@ Tk_CanvasPsOutline(
     Tk_Item *item,
     Tk_Outline *outline)
 {
-    char string[41], pattern[11];
+    char pattern[11];
     int i;
-    char *ptr, *str = string, *lptr = pattern;
+    char *ptr, *lptr = pattern;
     Tcl_Interp *interp = Canvas(canvas)->interp;
     double width = outline->width;
     Tk_Dash *dash = &outline->dash;
     XColor *color = outline->color;
     Pixmap stipple = outline->stipple;
     Tk_State state = item->state;
+    Tcl_Obj *psObj = GetPostscriptBuffer(interp);
 
     if (state == TK_STATE_NULL) {
 	state = Canvas(canvas)->canvas_state;
@@ -1380,7 +1399,7 @@ Tk_CanvasPsOutline(
 	    width = outline->activeWidth;
 	}
 	if (outline->activeDash.number > 0) {
-	    dash = &(outline->activeDash);
+	    dash = &outline->activeDash;
 	}
 	if (outline->activeColor != NULL) {
 	    color = outline->activeColor;
@@ -1393,7 +1412,7 @@ Tk_CanvasPsOutline(
 	    width = outline->disabledWidth;
 	}
 	if (outline->disabledDash.number > 0) {
-	    dash = &(outline->disabledDash);
+	    dash = &outline->disabledDash;
 	}
 	if (outline->disabledColor != NULL) {
 	    color = outline->disabledColor;
@@ -1402,66 +1421,65 @@ Tk_CanvasPsOutline(
 	    stipple = outline->disabledStipple;
 	}
     }
-    sprintf(string, "%.15g setlinewidth\n", width);
-    Tcl_AppendResult(interp, string, NULL);
 
-    if (dash->number > 10) {
-	str = ckalloc(1 + 4*dash->number);
-    } else if (dash->number < -5) {
-	str = ckalloc(1 - 8*dash->number);
-	lptr = ckalloc(1 - 2*dash->number);
-    }
+    Tcl_AppendPrintfToObj(psObj, "%.15g setlinewidth\n", width);
+
     ptr = ((unsigned) ABS(dash->number) > sizeof(char *)) ?
 	    dash->pattern.pt : dash->pattern.array;
+    Tcl_AppendToObj(psObj, "[", -1);
     if (dash->number > 0) {
-	char *ptr0 = ptr;
+	Tcl_Obj *converted;
+	char *p = ptr;
 
-	sprintf(str, "[%d", *ptr++ & 0xff);
-	i = dash->number-1;
-	while (i--) {
-	    sprintf(str+strlen(str), " %d", *ptr++ & 0xff);
+	converted = Tcl_ObjPrintf("%d", *p++ & 0xff);
+	for (i = dash->number-1 ; i>=0 ; i--) {
+	    Tcl_AppendPrintfToObj(converted, " %d", *p++ & 0xff);
 	}
-	Tcl_AppendResult(interp, str, NULL);
-	if (dash->number&1) {
-	    Tcl_AppendResult(interp, " ", str+1, NULL);
+	Tcl_AppendObjToObj(psObj, converted);
+	if (dash->number & 1) {
+	    Tcl_AppendToObj(psObj, " ", -1);
+	    Tcl_AppendObjToObj(psObj, converted);
 	}
-	sprintf(str, "] %d setdash\n", outline->offset);
-	Tcl_AppendResult(interp, str, NULL);
-	ptr = ptr0;
+	Tcl_DecrRefCount(converted);
+	Tcl_AppendPrintfToObj(psObj, "] %d setdash\n", outline->offset);
     } else if (dash->number < 0) {
-	if ((i = DashConvert(lptr, ptr, -dash->number, width)) != 0) {
-	    char *lptr0 = lptr;
+	if (dash->number < -5) {
+	    lptr = ckalloc(1 - 2*dash->number);
+	}
+	i = DashConvert(lptr, ptr, -dash->number, width);
+	if (i > 0) {
+	    char *p = lptr;
 
-	    sprintf(str, "[%d", *lptr++ & 0xff);
-	    while (--i) {
-		sprintf(str+strlen(str), " %d", *lptr++ & 0xff);
+	    Tcl_AppendPrintfToObj(psObj, "%d", *p++ & 0xff);
+	    for (; --i>0 ;) {
+		Tcl_AppendPrintfToObj(psObj, " %d", *p++ & 0xff);
 	    }
-	    Tcl_AppendResult(interp, str, NULL);
-	    sprintf(str, "] %d setdash\n", outline->offset);
-	    Tcl_AppendResult(interp, str, NULL);
-	    lptr = lptr0;
+	    Tcl_AppendPrintfToObj(psObj, "] %d setdash\n", outline->offset);
 	} else {
-	    Tcl_AppendResult(interp, "[] 0 setdash\n", NULL);
+	    Tcl_AppendToObj(psObj, "] 0 setdash\n", -1);
+	}
+	if (lptr != pattern) {
+	    ckfree(lptr);
 	}
     } else {
-	Tcl_AppendResult(interp, "[] 0 setdash\n", NULL);
-    }
-    if (str != string) {
-	ckfree(str);
-    }
-    if (lptr != pattern) {
-	ckfree(lptr);
+	Tcl_AppendToObj(psObj, "] 0 setdash\n", -1);
     }
+
     if (Tk_CanvasPsColor(interp, canvas, color) != TCL_OK) {
 	return TCL_ERROR;
     }
+
+    /*
+     * Note that psObj might hold an invalid reference now.
+     */
+
     if (stipple != None) {
-	Tcl_AppendResult(interp, "StrokeClip ", NULL);
+	Tcl_AppendToObj(GetPostscriptBuffer(interp), "StrokeClip ", -1);
 	if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK) {
 	    return TCL_ERROR;
 	}
     } else {
-	Tcl_AppendResult(interp, "stroke\n", NULL);
+	Tcl_AppendToObj(GetPostscriptBuffer(interp), "stroke\n", -1);
     }
 
     return TCL_OK;
@@ -1731,7 +1749,7 @@ TkCanvTranslatePath(
      * This is the loop that makes the four passes through the data.
      */
 
-    for (j=0; j<4; j++){
+    for (j=0; j<4; j++) {
 	double xClip = limit[j];
 	int inside = a[0] < xClip;
 	double priorY = a[1];
@@ -1742,7 +1760,7 @@ TkCanvTranslatePath(
 	 * rotated by 90 degrees clockwise.
 	 */
 
-	for (i=0; i<numVertex; i++){
+	for (i=0; i<numVertex; i++) {
 	    double x = a[i*2];
 	    double y = a[i*2 + 1];
 
@@ -1833,7 +1851,7 @@ TkCanvTranslatePath(
      * XPoints and translate the origin for the drawable.
      */
 
-    for (i=0; i<numVertex; i++){
+    for (i=0; i<numVertex; i++) {
 	TranslateAndAppendCoords(canvPtr, a[i*2], a[i*2+1], outArr, i);
     }
     if (tempArr != staticSpace) {
diff --git a/generic/tkCanvWind.c b/generic/tkCanvWind.c
index f2cce7d..f183b35 100644
--- a/generic/tkCanvWind.c
+++ b/generic/tkCanvWind.c
@@ -246,22 +246,21 @@ WinItemCoords(
     WindowItem *winItemPtr = (WindowItem *) itemPtr;
 
     if (objc == 0) {
-	Tcl_Obj *obj = Tcl_NewObj();
-	Tcl_Obj *subobj = Tcl_NewDoubleObj(winItemPtr->x);
-	Tcl_ListObjAppendElement(interp, obj, subobj);
-	subobj = Tcl_NewDoubleObj(winItemPtr->y);
-	Tcl_ListObjAppendElement(interp, obj, subobj);
-	Tcl_SetObjResult(interp, obj);
+	Tcl_Obj *objs[2];
+
+	objs[0] = Tcl_NewDoubleObj(winItemPtr->x);
+	objs[1] = Tcl_NewDoubleObj(winItemPtr->y);
+	Tcl_SetObjResult(interp, Tcl_NewListObj(2, objs));
     } else if (objc < 3) {
 	if (objc==1) {
 	    if (Tcl_ListObjGetElements(interp, objv[0], &objc,
 		    (Tcl_Obj ***) &objv) != TCL_OK) {
 		return TCL_ERROR;
 	    } else if (objc != 2) {
-		char buf[64 + TCL_INTEGER_SPACE];
-
-		sprintf(buf, "wrong # coordinates: expected 2, got %d", objc);
-		Tcl_SetResult(interp, buf, TCL_VOLATILE);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"wrong # coordinates: expected 2, got %d", objc));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "WINDOW",
+			NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -272,10 +271,9 @@ WinItemCoords(
 	}
 	ComputeWindowBbox(canvas, winItemPtr);
     } else {
-	char buf[64 + TCL_INTEGER_SPACE];
-
-	sprintf(buf, "wrong # coordinates: expected 0 or 2, got %d", objc);
-	Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"wrong # coordinates: expected 0 or 2, got %d", objc));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "WINDOW", NULL);
 	return TCL_ERROR;
     }
     return TCL_OK;
@@ -342,8 +340,7 @@ ConfigureWinItem(
 	     */
 
 	    parent = Tk_Parent(winItemPtr->tkwin);
-	    for (ancestor = canvasTkwin; ;
-		    ancestor = Tk_Parent(ancestor)) {
+	    for (ancestor = canvasTkwin ;; ancestor = Tk_Parent(ancestor)) {
 		if (ancestor == parent) {
 		    break;
 		}
@@ -375,8 +372,10 @@ ConfigureWinItem(
     return TCL_OK;
 
   badWindow:
-    Tcl_AppendResult(interp, "can't use ", Tk_PathName(winItemPtr->tkwin),
-	    " in a window item of this canvas", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "can't use %s in a window item of this canvas",
+	    Tk_PathName(winItemPtr->tkwin)));
+    Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "HIERARCHY", NULL);
     winItemPtr->tkwin = NULL;
     return TCL_ERROR;
 }
@@ -827,45 +826,44 @@ CanvasPsWindow(
     double x, double y,		/* origin of window. */
     int width, int height)	/* width/height of window. */
 {
-    char buffer[256];
     XImage *ximage;
     int result;
-    Tcl_DString buffer1, buffer2;
 #ifdef X_GetImage
     Tk_ErrorHandler handle;
 #endif
+    Tcl_Obj *cmdObj, *psObj;
+    Tcl_InterpState interpState = Tcl_SaveInterpState(interp, TCL_OK);
+
+    /*
+     * Locate the subwindow within the wider window.
+     */
 
-    sprintf(buffer, "\n%%%% %s item (%s, %d x %d)\n%.15g %.15g translate\n",
+    psObj = Tcl_ObjPrintf(
+	    "\n%%%% %s item (%s, %d x %d)\n"	// Comment
+	    "%.15g %.15g translate\n",		// Position
 	    Tk_Class(tkwin), Tk_PathName(tkwin), width, height, x, y);
-    Tcl_AppendResult(interp, buffer, NULL);
 
     /*
      * First try if the widget has its own "postscript" command. If it exists,
      * this will produce much better postscript than when a pixmap is used.
      */
 
-    Tcl_DStringInit(&buffer1);
-    Tcl_DStringInit(&buffer2);
-    Tcl_DStringGetResult(interp, &buffer2);
-    sprintf(buffer, "%s postscript -prolog 0\n", Tk_PathName(tkwin));
-    result = Tcl_Eval(interp, buffer);
-    Tcl_DStringGetResult(interp, &buffer1);
-    Tcl_DStringResult(interp, &buffer2);
-    Tcl_DStringFree(&buffer2);
+    Tcl_ResetResult(interp);
+    cmdObj = Tcl_ObjPrintf("%s postscript -prolog 0", Tk_PathName(tkwin));
+    Tcl_IncrRefCount(cmdObj);
+    result = Tcl_EvalObjEx(interp, cmdObj, 0);
+    Tcl_DecrRefCount(cmdObj);
 
     if (result == TCL_OK) {
-	Tcl_AppendResult(interp, "50 dict begin\nsave\ngsave\n", NULL);
-	sprintf(buffer, "0 %d moveto %d 0 rlineto 0 -%d rlineto -%d",
-		height, width, height, width);
-	Tcl_AppendResult(interp, buffer, NULL);
-	Tcl_AppendResult(interp, " 0 rlineto closepath\n",
+	Tcl_AppendPrintfToObj(psObj,
+		"50 dict begin\nsave\ngsave\n"
+		"0 %d moveto %d 0 rlineto 0 -%d rlineto -%d 0 rlineto closepath\n"
 		"1.000 1.000 1.000 setrgbcolor AdjustColor\nfill\ngrestore\n",
-		Tcl_DStringValue(&buffer1), "\nrestore\nend\n\n\n", NULL);
-	Tcl_DStringFree(&buffer1);
-
-	return result;
+		height, width, height, width);
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+	Tcl_AppendToObj(psObj, "\nrestore\nend\n\n\n", -1);
+	goto done;
     }
-    Tcl_DStringFree(&buffer1);
 
     /*
      * If the window is off the screen it will generate a BadMatch/XError. We
@@ -890,13 +888,27 @@ CanvasPsWindow(
 #endif
 
     if (ximage == NULL) {
-	return TCL_OK;
+	result = TCL_OK;
+    } else {
+	Tcl_ResetResult(interp);
+	result = TkPostscriptImage(interp, tkwin, Canvas(canvas)->psInfo,
+		ximage, 0, 0, width, height);
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+	XDestroyImage(ximage);
     }
 
-    result = TkPostscriptImage(interp, tkwin, Canvas(canvas)->psInfo, ximage,
-	    0, 0, width, height);
+    /*
+     * Plug the accumulated postscript back into the result.
+     */
 
-    XDestroyImage(ximage);
+  done:
+    if (result == TCL_OK) {
+	(void) Tcl_RestoreInterpState(interp, interpState);
+	Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    } else {
+	Tcl_DiscardInterpState(interpState);
+    }
+    Tcl_DecrRefCount(psObj);
     return result;
 }
 
diff --git a/generic/tkCanvas.c b/generic/tkCanvas.c
index 14d8261..07f1cfe 100644
--- a/generic/tkCanvas.c
+++ b/generic/tkCanvas.c
@@ -269,7 +269,7 @@ static int		ConfigureCanvas(Tcl_Interp *interp,
 			    Tcl_Obj *const *argv, int flags);
 static void		DestroyCanvas(char *memPtr);
 static void		DisplayCanvas(ClientData clientData);
-static void		DoItem(Tcl_Interp *interp,
+static void		DoItem(Tcl_Obj *accumObj,
 			    Tk_Item *itemPtr, Tk_Uid tag);
 static void		EventuallyRedrawItem(TkCanvas *canvasPtr,
 			    Tk_Item *itemPtr);
@@ -333,10 +333,10 @@ static const Tk_ClassProcs canvasClass = {
 
 #ifdef USE_OLD_TAG_SEARCH
 #define FIRST_CANVAS_ITEM_MATCHING(objPtr,searchPtrPtr,errorExitClause) \
-    (itemPtr) = StartTagSearch(canvasPtr,(objPtr),&search)
+    itemPtr = StartTagSearch(canvasPtr,(objPtr),&search)
 #define FOR_EVERY_CANVAS_ITEM_MATCHING(objPtr,searchPtrPtr,errorExitClause) \
-    for ((itemPtr) = StartTagSearch(canvasPtr, (objPtr), &search); \
-	    (itemPtr) != NULL; (itemPtr) = NextItem(&search))
+    for (itemPtr = StartTagSearch(canvasPtr, (objPtr), &search); \
+	    itemPtr != NULL; itemPtr = NextItem(&search))
 #define FIND_ITEMS(objPtr, n) \
     FindItems(interp, canvasPtr, objc, objv, (objPtr), (n))
 #define RELINK_ITEMS(objPtr, itemPtr) \
@@ -928,8 +928,10 @@ CanvasWidgetCmd(
 	    }
 
 	    if (object == NULL) {
-		Tcl_AppendResult(interp, "item \"", Tcl_GetString(objv[2]),
-			"\" doesn't exist", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"item \"%s\" doesn't exist", Tcl_GetString(objv[2])));
+		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "CANVAS_ITEM",
+			Tcl_GetString(objv[2]), NULL);
 		result = TCL_ERROR;
 		goto done;
 	    }
@@ -953,8 +955,10 @@ CanvasWidgetCmd(
 	    }
 
 	    if (object == 0) {
-		Tcl_AppendResult(interp, "item \"", Tcl_GetString(objv[2]),
-			"\" doesn't exist", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"item \"%s\" doesn't exist", Tcl_GetString(objv[2])));
+		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "CANVAS_ITEM",
+			Tcl_GetString(objv[2]), NULL);
 		result = TCL_ERROR;
 		goto done;
 	    }
@@ -1030,10 +1034,10 @@ CanvasWidgetCmd(
 		    |KeyReleaseMask|PointerMotionMask|VirtualEventMask)) {
 		Tk_DeleteBinding(interp, canvasPtr->bindingTable,
 			object, Tcl_GetString(objv[3]));
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "requested illegal events; ",
-			"only key, button, motion, enter, leave, and virtual",
-			" events may be used", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"requested illegal events; only key, button, motion,"
+			" enter, leave, and virtual events may be used", -1));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "BAD_EVENTS", NULL);
 		result = TCL_ERROR;
 		goto done;
 	    }
@@ -1274,8 +1278,10 @@ CanvasWidgetCmd(
 	Tcl_MutexUnlock(&typeListMutex);
 	if (matchPtr == NULL) {
 	badType:
-	    Tcl_AppendResult(interp,
-		    "unknown or ambiguous item type \"", arg, "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "unknown or ambiguous item type \"%s\"", arg));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "CANVAS_ITEM_TYPE", arg,
+		    NULL);
 	    result = TCL_ERROR;
 	    goto done;
 	}
@@ -1501,9 +1507,13 @@ CanvasWidgetCmd(
 	FIRST_CANVAS_ITEM_MATCHING(objv[2], &searchPtr, goto done);
 	if (itemPtr != NULL) {
 	    int i;
+	    Tcl_Obj *resultObj = Tcl_NewObj();
+
 	    for (i = 0; i < itemPtr->numTags; i++) {
-		Tcl_AppendElement(interp, (char *) itemPtr->tagPtr[i]);
+		Tcl_ListObjAppendElement(NULL, resultObj,
+			Tcl_NewStringObj(itemPtr->tagPtr[i], -1));
 	    }
+	    Tcl_SetObjResult(interp, resultObj);
 	}
 	break;
     case CANV_ICURSOR: {
@@ -1545,8 +1555,10 @@ CanvasWidgetCmd(
 	    }
 	}
 	if (itemPtr == NULL) {
-	    Tcl_AppendResult(interp, "can't find an indexable item \"",
-		    Tcl_GetString(objv[2]), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't find an indexable item \"%s\"",
+		    Tcl_GetString(objv[2])));
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "INDEXABLE_ITEM", NULL);
 	    result = TCL_ERROR;
 	    goto done;
 	}
@@ -1647,8 +1659,10 @@ CanvasWidgetCmd(
 	} else {
 	    FIRST_CANVAS_ITEM_MATCHING(objv[3], &searchPtr, goto done);
 	    if (itemPtr == NULL) {
-		Tcl_AppendResult(interp, "tag \"", Tcl_GetString(objv[3]),
-			"\" doesn't match any items", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"tagOrId \"%s\" doesn't match any items",
+			Tcl_GetString(objv[3])));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "ITEM", NULL);
 		result = TCL_ERROR;
 		goto done;
 	    }
@@ -1772,8 +1786,10 @@ CanvasWidgetCmd(
 		prevPtr = itemPtr;
 	    }
 	    if (prevPtr == NULL) {
-		Tcl_AppendResult(interp, "tagOrId \"", Tcl_GetString(objv[3]),
-			"\" doesn't match any items", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"tagOrId \"%s\" doesn't match any items",
+			Tcl_GetString(objv[3])));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "ITEM", NULL);
 		result = TCL_ERROR;
 		goto done;
 	    }
@@ -1847,7 +1863,9 @@ CanvasWidgetCmd(
 	    goto done;
 	}
 	if ((xScale == 0.0) || (yScale == 0.0)) {
-	    Tcl_SetResult(interp, "scale factor cannot be zero", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "scale factor cannot be zero", -1));
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "BAD_SCALE", NULL);
 	    result = TCL_ERROR;
 	    goto done;
 	}
@@ -1925,9 +1943,11 @@ CanvasWidgetCmd(
 		}
 	    }
 	    if (itemPtr == NULL) {
-		Tcl_AppendResult(interp,
-			"can't find an indexable and selectable item \"",
-			Tcl_GetString(objv[3]), "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"can't find an indexable and selectable item \"%s\"",
+			Tcl_GetString(objv[3])));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "SELECTABLE_ITEM",
+			NULL);
 		result = TCL_ERROR;
 		goto done;
 	    }
@@ -2019,6 +2039,7 @@ CanvasWidgetCmd(
 	int newX = 0;		/* Initialization needed only to prevent gcc
 				 * warnings. */
 	double fraction;
+	const char **args;
 
 	if (objc == 2) {
 	    Tcl_SetObjResult(interp, ScrollFractions(
@@ -2026,39 +2047,37 @@ CanvasWidgetCmd(
 		    canvasPtr->xOrigin + Tk_Width(canvasPtr->tkwin)
 		    - canvasPtr->inset, canvasPtr->scrollX1,
 		    canvasPtr->scrollX2));
-	} else {
-	    const char **args = TkGetStringsFromObjs(objc, objv);
+	    break;
+	}
 
-	    type = Tk_GetScrollInfo(interp, objc, args, &fraction, &count);
-	    if (args != NULL) {
-		ckfree(args);
-	    }
-	    switch (type) {
-	    case TK_SCROLL_ERROR:
-		result = TCL_ERROR;
-		goto done;
-	    case TK_SCROLL_MOVETO:
-		newX = canvasPtr->scrollX1 - canvasPtr->inset
-			+ (int) (fraction * (canvasPtr->scrollX2
-			- canvasPtr->scrollX1) + 0.5);
-		break;
-	    case TK_SCROLL_PAGES:
-		newX = (int) (canvasPtr->xOrigin + count * .9
+	args = TkGetStringsFromObjs(objc, objv);
+	type = Tk_GetScrollInfo(interp, objc, args, &fraction, &count);
+	if (args != NULL) {
+	    ckfree(args);
+	}
+	switch (type) {
+	case TK_SCROLL_ERROR:
+	    result = TCL_ERROR;
+	    goto done;
+	case TK_SCROLL_MOVETO:
+	    newX = canvasPtr->scrollX1 - canvasPtr->inset
+		    + (int) (fraction * (canvasPtr->scrollX2
+			    - canvasPtr->scrollX1) + 0.5);
+	    break;
+	case TK_SCROLL_PAGES:
+	    newX = (int) (canvasPtr->xOrigin + count * .9
+		    * (Tk_Width(canvasPtr->tkwin) - 2*canvasPtr->inset));
+	    break;
+	case TK_SCROLL_UNITS:
+	    if (canvasPtr->xScrollIncrement > 0) {
+		newX = canvasPtr->xOrigin + count*canvasPtr->xScrollIncrement;
+	    } else {
+		newX = (int) (canvasPtr->xOrigin + count * .1
 			* (Tk_Width(canvasPtr->tkwin) - 2*canvasPtr->inset));
-		break;
-	    case TK_SCROLL_UNITS:
-		if (canvasPtr->xScrollIncrement > 0) {
-		    newX = canvasPtr->xOrigin
-			    + count*canvasPtr->xScrollIncrement;
-		} else {
-		    newX = (int) (canvasPtr->xOrigin + count * .1
-			    * (Tk_Width(canvasPtr->tkwin)
-			    - 2*canvasPtr->inset));
-		}
-		break;
 	    }
-	    CanvasSetOrigin(canvasPtr, newX, canvasPtr->yOrigin);
+	    break;
 	}
+	CanvasSetOrigin(canvasPtr, newX, canvasPtr->yOrigin);
 	break;
     }
     case CANV_YVIEW: {
@@ -2066,6 +2085,7 @@ CanvasWidgetCmd(
 	int newY = 0;		/* Initialization needed only to prevent gcc
 				 * warnings. */
 	double fraction;
+	const char **args;
 
 	if (objc == 2) {
 	    Tcl_SetObjResult(interp, ScrollFractions(
@@ -2073,40 +2093,36 @@ CanvasWidgetCmd(
 		    canvasPtr->yOrigin + Tk_Height(canvasPtr->tkwin)
 		    - canvasPtr->inset,
 		    canvasPtr->scrollY1, canvasPtr->scrollY2));
-	} else {
-	    const char **args = TkGetStringsFromObjs(objc, objv);
+	    break;
+	}
 
-	    type = Tk_GetScrollInfo(interp, objc, args, &fraction, &count);
-	    if (args != NULL) {
-		ckfree(args);
-	    }
-	    switch (type) {
-	    case TK_SCROLL_ERROR:
-		result = TCL_ERROR;
-		goto done;
-	    case TK_SCROLL_MOVETO:
-		newY = canvasPtr->scrollY1 - canvasPtr->inset
-			+ (int) (fraction*(canvasPtr->scrollY2
-			- canvasPtr->scrollY1) + 0.5);
-		break;
-	    case TK_SCROLL_PAGES:
-		newY = (int) (canvasPtr->yOrigin + count * .9
-			* (Tk_Height(canvasPtr->tkwin)
-			- 2*canvasPtr->inset));
-		break;
-	    case TK_SCROLL_UNITS:
-		if (canvasPtr->yScrollIncrement > 0) {
-		    newY = canvasPtr->yOrigin
-			    + count*canvasPtr->yScrollIncrement;
-		} else {
-		    newY = (int) (canvasPtr->yOrigin + count * .1
-			    * (Tk_Height(canvasPtr->tkwin)
-			    - 2*canvasPtr->inset));
-		}
-		break;
+	args = TkGetStringsFromObjs(objc, objv);
+	type = Tk_GetScrollInfo(interp, objc, args, &fraction, &count);
+	if (args != NULL) {
+	    ckfree(args);
+	}
+	switch (type) {
+	case TK_SCROLL_ERROR:
+	    result = TCL_ERROR;
+	    goto done;
+	case TK_SCROLL_MOVETO:
+	    newY = canvasPtr->scrollY1 - canvasPtr->inset + (int) (
+		    fraction*(canvasPtr->scrollY2-canvasPtr->scrollY1) + 0.5);
+	    break;
+	case TK_SCROLL_PAGES:
+	    newY = (int) (canvasPtr->yOrigin + count * .9
+		    * (Tk_Height(canvasPtr->tkwin) - 2*canvasPtr->inset));
+	    break;
+	case TK_SCROLL_UNITS:
+	    if (canvasPtr->yScrollIncrement > 0) {
+		newY = canvasPtr->yOrigin + count*canvasPtr->yScrollIncrement;
+	    } else {
+		newY = (int) (canvasPtr->yOrigin + count * .1
+			* (Tk_Height(canvasPtr->tkwin) - 2*canvasPtr->inset));
 	    }
-	    CanvasSetOrigin(canvasPtr, canvasPtr->xOrigin, newY);
+	    break;
 	}
+	CanvasSetOrigin(canvasPtr, canvasPtr->xOrigin, newY);
 	break;
     }
     }
@@ -2302,8 +2318,9 @@ ConfigureCanvas(
 	    return TCL_ERROR;
 	}
 	if (argc2 != 4) {
-	    Tcl_AppendResult(interp, "bad scrollRegion \"",
-		    canvasPtr->regionString, "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad scrollRegion \"%s\"", canvasPtr->regionString));
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SCROLL_REGION", NULL);
 	badRegion:
 	    ckfree(canvasPtr->regionString);
 	    ckfree(argv2);
@@ -3583,8 +3600,10 @@ TagSearchScanExpr(
 
 	    case '!':		/* Negate next tag or subexpr */
 		if (looking_for_tag > 1) {
-		    Tcl_AppendResult(interp,
-			    "Too many '!' in tag search expression", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "too many '!' in tag search expression", -1));
+		    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			    "COMPLEXITY", NULL);
 		    return TCL_ERROR;
 		}
 		looking_for_tag++;
@@ -3631,15 +3650,18 @@ TagSearchScanExpr(
 		    *tag++ = c;
 		}
 		if (!found_endquote) {
-		    Tcl_AppendResult(interp,
-			    "Missing endquote in tag search expression",
-			    NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "missing endquote in tag search expression", -1));
+		    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			    "ENDQUOTE", NULL);
 		    return TCL_ERROR;
 		}
 		if (!(tag - searchPtr->rewritebuffer)) {
-		    Tcl_AppendResult(interp,
-			    "Null quoted tag string in tag search expression",
-			    NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "null quoted tag string in tag search expression",
+			    -1));
+		    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			    "EMPTY", NULL);
 		    return TCL_ERROR;
 		}
 		*tag++ = '\0';
@@ -3653,9 +3675,10 @@ TagSearchScanExpr(
 	    case '|':
 	    case '^':
 	    case ')':
-		Tcl_AppendResult(interp,
-			"Unexpected operator in tag search expression",
-			NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"unexpected operator in tag search expression", -1));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			"UNEXPECTED", NULL);
 		return TCL_ERROR;
 
 	    default:		/* Unquoted tag string */
@@ -3716,8 +3739,10 @@ TagSearchScanExpr(
 	    case '&':		/* AND operator */
 		c = searchPtr->string[searchPtr->stringIndex++];
 		if (c != '&') {
-		    Tcl_AppendResult(interp,
-			    "Singleton '&' in tag search expression", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "singleton '&' in tag search expression", -1));
+		    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			    "INCOMPLETE_OP", NULL);
 		    return TCL_ERROR;
 		}
 		expr->uids[expr->index++] = searchUids->andUid;
@@ -3727,8 +3752,10 @@ TagSearchScanExpr(
 	    case '|':		/* OR operator */
 		c = searchPtr->string[searchPtr->stringIndex++];
 		if (c != '|') {
-		    Tcl_AppendResult(interp,
-			    "Singleton '|' in tag search expression", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "singleton '|' in tag search expression", -1));
+		    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			    "INCOMPLETE_OP", NULL);
 		    return TCL_ERROR;
 		}
 		expr->uids[expr->index++] = searchUids->orUid;
@@ -3745,8 +3772,10 @@ TagSearchScanExpr(
 		goto breakwhile;
 
 	    default:		/* syntax error */
-		Tcl_AppendResult(interp,
-			"Invalid boolean operator in tag search expression",
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"invalid boolean operator in tag search expression",
+			-1));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH", "BAD_OP",
 			NULL);
 		return TCL_ERROR;
 	    }
@@ -3757,7 +3786,9 @@ TagSearchScanExpr(
     if (found_tag && !looking_for_tag) {
 	return TCL_OK;
     }
-    Tcl_AppendResult(interp, "Missing tag in tag search expression", NULL);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+	    "missing tag in tag search expression", -1));
+    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH", "NO_TAG", NULL);
     return TCL_ERROR;
 }
 
@@ -4138,23 +4169,23 @@ TagSearchNext(
  * DoItem --
  *
  *	This is a utility function called by FindItems. It either adds
- *	itemPtr's id to the result forming in interp, or it adds a new tag to
+ *	itemPtr's id to the list being constructed, or it adds a new tag to
  *	itemPtr, depending on the value of tag.
  *
  * Results:
  *	None.
  *
  * Side effects:
- *	If tag is NULL then itemPtr's id is added as a list element to the
- *	interp's result; otherwise tag is added to itemPtr's list of tags.
+ *	If tag is NULL then itemPtr's id is added as an element to the
+ *	supplied object; otherwise tag is added to itemPtr's list of tags.
  *
  *--------------------------------------------------------------
  */
 
 static void
 DoItem(
-    Tcl_Interp *interp,		/* Interpreter in which to (possibly) record
-				 * item id. */
+    Tcl_Obj *accumObj,		/* Object in which to (possibly) record item
+				 * id. */
     Tk_Item *itemPtr,		/* Item to (possibly) modify. */
     Tk_Uid tag)			/* Tag to add to those already present for
 				 * item, or NULL. */
@@ -4167,10 +4198,7 @@ DoItem(
      */
 
     if (tag == NULL) {
-	char msg[TCL_INTEGER_SPACE];
-
-	sprintf(msg, "%d", itemPtr->id);
-	Tcl_AppendElement(interp, msg);
+	Tcl_ListObjAppendElement(NULL, accumObj, Tcl_NewIntObj(itemPtr->id));
 	return;
     }
 
@@ -4257,6 +4285,7 @@ FindItems(
     Tk_Item *itemPtr;
     Tk_Uid uid;
     int index, result;
+    Tcl_Obj *resultObj;
     static const char *const optionStrings[] = {
 	"above", "all", "below", "closest",
 	"enclosed", "overlapping", "withtag", NULL
@@ -4288,7 +4317,9 @@ FindItems(
 	    lastPtr = itemPtr;
 	}
 	if ((lastPtr != NULL) && (lastPtr->nextPtr != NULL)) {
-	    DoItem(interp, lastPtr->nextPtr, uid);
+	    resultObj = Tcl_NewObj();
+	    DoItem(resultObj, lastPtr->nextPtr, uid);
+	    Tcl_SetObjResult(interp, resultObj);
 	}
 	break;
     }
@@ -4298,10 +4329,12 @@ FindItems(
 	    return TCL_ERROR;
 	}
 
+	resultObj = Tcl_NewObj();
 	for (itemPtr = canvasPtr->firstItemPtr; itemPtr != NULL;
 		itemPtr = itemPtr->nextPtr) {
-	    DoItem(interp, itemPtr, uid);
+	    DoItem(resultObj, itemPtr, uid);
 	}
+	Tcl_SetObjResult(interp, resultObj);
 	break;
 
     case CANV_BELOW:
@@ -4311,10 +4344,10 @@ FindItems(
 	}
 	FIRST_CANVAS_ITEM_MATCHING(objv[first+1], searchPtrPtr,
 		return TCL_ERROR);
-	if (itemPtr != NULL) {
-	    if (itemPtr->prevPtr != NULL) {
-		DoItem(interp, itemPtr->prevPtr, uid);
-	    }
+	if ((itemPtr != NULL) && (itemPtr->prevPtr != NULL)) {
+	    resultObj = Tcl_NewObj();
+	    DoItem(resultObj, itemPtr->prevPtr, uid);
+	    Tcl_SetObjResult(interp, resultObj);
 	}
 	break;
     case CANV_CLOSEST: {
@@ -4339,8 +4372,8 @@ FindItems(
 		return TCL_ERROR;
 	    }
 	    if (halo < 0.0) {
-		Tcl_AppendResult(interp, "can't have negative halo value \"",
-			Tcl_GetString(objv[3]), "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"can't have negative halo value \"%f\"", halo));
 		return TCL_ERROR;
 	    }
 	} else {
@@ -4404,7 +4437,9 @@ FindItems(
 		    itemPtr = canvasPtr->firstItemPtr;
 		}
 		if (itemPtr == startPtr) {
-		    DoItem(interp, closestPtr, uid);
+		    resultObj = Tcl_NewObj();
+		    DoItem(resultObj, closestPtr, uid);
+		    Tcl_SetObjResult(interp, resultObj);
 		    return TCL_OK;
 		}
 		if (itemPtr->state == TK_STATE_HIDDEN ||
@@ -4442,10 +4477,16 @@ FindItems(
 	    Tcl_WrongNumArgs(interp, first+1, objv, "tagOrId");
 	    return TCL_ERROR;
 	}
+	resultObj = Tcl_NewObj();
 	FOR_EVERY_CANVAS_ITEM_MATCHING(objv[first+1], searchPtrPtr,
-		return TCL_ERROR) {
-	    DoItem(interp, itemPtr, uid);
+		goto badWithTagSearch) {
+	    DoItem(resultObj, itemPtr, uid);
 	}
+	Tcl_SetObjResult(interp, resultObj);
+	return TCL_OK;
+    badWithTagSearch:
+	Tcl_DecrRefCount(resultObj);
+	return TCL_ERROR;
     }
     return TCL_OK;
 }
@@ -4490,6 +4531,7 @@ FindArea(
     double rect[4], tmp;
     int x1, y1, x2, y2;
     Tk_Item *itemPtr;
+    Tcl_Obj *resultObj;
 
     if ((Tk_CanvasGetCoordFromObj(interp, (Tk_Canvas) canvasPtr, objv[0],
 		&rect[0]) != TCL_OK)
@@ -4517,6 +4559,7 @@ FindArea(
     y1 = (int) (rect[1] - 1.0);
     x2 = (int) (rect[2] + 1.0);
     y2 = (int) (rect[3] + 1.0);
+    resultObj = Tcl_NewObj();
     for (itemPtr = canvasPtr->firstItemPtr; itemPtr != NULL;
 	    itemPtr = itemPtr->nextPtr) {
 	if (itemPtr->state == TK_STATE_HIDDEN ||
@@ -4529,9 +4572,10 @@ FindArea(
 	    continue;
 	}
 	if (ItemOverlap(canvasPtr, itemPtr, rect) >= enclosed) {
-	    DoItem(interp, itemPtr, uid);
+	    DoItem(resultObj, itemPtr, uid);
 	}
     }
+    Tcl_SetObjResult(interp, resultObj);
     return TCL_OK;
 }
 
diff --git a/generic/tkClipboard.c b/generic/tkClipboard.c
index 043c167..604fa98 100644
--- a/generic/tkClipboard.c
+++ b/generic/tkClipboard.c
@@ -367,10 +367,12 @@ Tk_ClipboardAppend(
 	Tk_CreateSelHandler(dispPtr->clipWindow, dispPtr->clipboardAtom,
 		type, ClipboardHandler, targetPtr, format);
     } else if (targetPtr->format != format) {
-	Tcl_AppendResult(interp, "format \"", Tk_GetAtomName(tkwin, format),
-		"\" does not match current format \"",
-		Tk_GetAtomName(tkwin, targetPtr->format),"\" for ",
-		Tk_GetAtomName(tkwin, type), NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"format \"%s\" does not match current format \"%s\" for %s",
+		Tk_GetAtomName(tkwin, format),
+		Tk_GetAtomName(tkwin, targetPtr->format),
+		Tk_GetAtomName(tkwin, type)));
+	Tcl_SetErrorCode(interp, "TK", "CLIPBOARD", "FORMAT_MISMATCH", NULL);
 	return TCL_ERROR;
     }
 
@@ -474,8 +476,9 @@ Tk_ClipboardObjCmd(
 
 	    i++;
 	    if (i >= objc) {
-		Tcl_AppendResult(interp, "value for \"", string,
-			"\" missing", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"value for \"%s\" missing", string));
+		Tcl_SetErrorCode(interp, "TK", "CLIPBOARD", "VALUE", NULL);
 		return TCL_ERROR;
 	    }
 	    switch ((enum appendOptions) subIndex) {
@@ -563,8 +566,9 @@ Tk_ClipboardObjCmd(
 	    }
 	    i++;
 	    if (i >= objc) {
-		Tcl_AppendResult(interp, "value for \"", string,
-			"\" missing", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"value for \"%s\" missing", string));
+		Tcl_SetErrorCode(interp, "TK", "CLIPBOARD", "VALUE", NULL);
 		return TCL_ERROR;
 	    }
 	    switch ((enum getOptions) subIndex) {
@@ -699,12 +703,11 @@ ClipboardGetProc(
 				 * selection. */
     Tcl_Interp *interp,		/* Interpreter used for error reporting (not
 				 * used). */
-    const char *portion)		/* New information to be appended. */
+    const char *portion)	/* New information to be appended. */
 {
     Tcl_DStringAppend((Tcl_DString *) clientData, portion, -1);
     return TCL_OK;
 }
-
 
 /*
  * Local Variables:
diff --git a/generic/tkCmds.c b/generic/tkCmds.c
index 63f626e..4e9494b 100644
--- a/generic/tkCmds.c
+++ b/generic/tkCmds.c
@@ -233,7 +233,7 @@ Tk_BindObjCmd(
 	    Tcl_ResetResult(interp);
 	    return TCL_OK;
 	}
-	Tcl_SetResult(interp, (char *) command, TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(command, -1));
     } else {
 	Tk_GetAllBindings(interp, winPtr->mainPtr->bindingTable, object);
     }
@@ -361,30 +361,28 @@ Tk_BindtagsObjCmd(
     }
     if (objc == 2) {
 	listPtr = Tcl_NewObj();
-	Tcl_IncrRefCount(listPtr);
 	if (winPtr->numTags == 0) {
-	    Tcl_ListObjAppendElement(interp, listPtr,
+	    Tcl_ListObjAppendElement(NULL, listPtr,
 		    Tcl_NewStringObj(winPtr->pathName, -1));
-	    Tcl_ListObjAppendElement(interp, listPtr,
+	    Tcl_ListObjAppendElement(NULL, listPtr,
 		    Tcl_NewStringObj(winPtr->classUid, -1));
 	    winPtr2 = winPtr;
 	    while ((winPtr2 != NULL) && !(Tk_TopWinHierarchy(winPtr2))) {
 		winPtr2 = winPtr2->parentPtr;
 	    }
 	    if ((winPtr != winPtr2) && (winPtr2 != NULL)) {
-		Tcl_ListObjAppendElement(interp, listPtr,
+		Tcl_ListObjAppendElement(NULL, listPtr,
 			Tcl_NewStringObj(winPtr2->pathName, -1));
 	    }
-	    Tcl_ListObjAppendElement(interp, listPtr,
+	    Tcl_ListObjAppendElement(NULL, listPtr,
 		    Tcl_NewStringObj("all", -1));
 	} else {
 	    for (i = 0; i < winPtr->numTags; i++) {
-		Tcl_ListObjAppendElement(interp, listPtr,
-			Tcl_NewStringObj((char *)winPtr->tagPtr[i], -1));
+		Tcl_ListObjAppendElement(NULL, listPtr,
+			Tcl_NewStringObj((char *) winPtr->tagPtr[i], -1));
 	    }
 	}
 	Tcl_SetObjResult(interp, listPtr);
-	Tcl_DecrRefCount(listPtr);
 	return TCL_OK;
     }
     if (winPtr->tagPtr != NULL) {
@@ -555,9 +553,15 @@ Tk_LowerObjCmd(
 	}
     }
     if (Tk_RestackWindow(tkwin, Below, other) != TCL_OK) {
-	Tcl_AppendResult(interp, "can't lower \"", Tcl_GetString(objv[1]),
-		"\" below \"", (other ? Tcl_GetString(objv[2]) : ""),
-		"\"", NULL);
+	if (other) {
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't lower \"%s\" below \"%s\"",
+		    Tcl_GetString(objv[1]), Tcl_GetString(objv[2])));
+	} else {
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't lower \"%s\" to bottom", Tcl_GetString(objv[1])));
+	}
+	Tcl_SetErrorCode(interp, "TK", "RESTACK", "LOWER", NULL);
 	return TCL_ERROR;
     }
     return TCL_OK;
@@ -609,9 +613,15 @@ Tk_RaiseObjCmd(
 	}
     }
     if (Tk_RestackWindow(tkwin, Above, other) != TCL_OK) {
-	Tcl_AppendResult(interp, "can't raise \"", Tcl_GetString(objv[1]),
-		"\" above \"", (other ? Tcl_GetString(objv[2]) : ""),
-		"\"", NULL);
+	if (other) {
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't raise \"%s\" above \"%s\"",
+		    Tcl_GetString(objv[1]), Tcl_GetString(objv[2])));
+	} else {
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't raise \"%s\" to top", Tcl_GetString(objv[1])));
+	}
+	Tcl_SetErrorCode(interp, "TK", "RESTACK", "RAISE", NULL);
 	return TCL_ERROR;
     }
     return TCL_OK;
@@ -675,9 +685,9 @@ AppnameCmd(
     const char *string;
 
     if (Tcl_IsSafe(interp)) {
-	Tcl_SetResult(interp,
-		"appname not accessible in a safe interpreter",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"appname not accessible in a safe interpreter", -1));
+	Tcl_SetErrorCode(interp, "TK", "SAFE", "APPLICATION", NULL);
 	return TCL_ERROR;
     }
 
@@ -691,7 +701,7 @@ AppnameCmd(
 	string = Tcl_GetString(objv[1]);
 	winPtr->nameUid = Tk_GetUid(Tk_SetAppName(tkwin, string));
     }
-    Tcl_AppendResult(interp, winPtr->nameUid, NULL);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(winPtr->nameUid, -1));
     return TCL_OK;
 }
 
@@ -800,8 +810,9 @@ ScalingCmd(
     double d;
 
     if (Tcl_IsSafe(interp)) {
-	Tcl_SetResult(interp, "scaling not accessible in a safe interpreter",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"scaling not accessible in a safe interpreter", -1));
+	Tcl_SetErrorCode(interp, "TK", "SAFE", "SCALING", NULL);
 	return TCL_ERROR;
     }
 
@@ -849,9 +860,9 @@ UseinputmethodsCmd(
     int skip;
 
     if (Tcl_IsSafe(interp)) {
-	Tcl_SetResult(interp,
-		"useinputmethods not accessible in a safe interpreter",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"useinputmethods not accessible in a safe interpreter", -1));
+	Tcl_SetErrorCode(interp, "TK", "SAFE", "INPUT_METHODS", NULL);
 	return TCL_ERROR;
     }
 
@@ -933,22 +944,22 @@ InactiveCmd(
 	inactive = (Tcl_IsSafe(interp) ? -1 :
 		Tk_GetUserInactiveTime(Tk_Display(tkwin)));
 	Tcl_SetObjResult(interp, Tcl_NewLongObj(inactive));
-
     } else if (objc - skip == 2) {
 	const char *string;
 
 	string = Tcl_GetString(objv[objc-1]);
 	if (strcmp(string, "reset") != 0) {
-	    Tcl_Obj *msg = Tcl_NewStringObj("bad option \"", -1);
-
-	    Tcl_AppendStringsToObj(msg, string, "\": must be reset", NULL);
-	    Tcl_SetObjResult(interp, msg);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad option \"%s\": must be reset", string));
+	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "option",
+		    string, NULL);
 	    return TCL_ERROR;
 	}
 	if (Tcl_IsSafe(interp)) {
-	    Tcl_SetResult(interp,
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		    "resetting the user inactivity timer "
-		    "is not allowed in a safe interpreter", TCL_STATIC);
+		    "is not allowed in a safe interpreter", -1));
+	    Tcl_SetErrorCode(interp, "TK", "SAFE", "INACTIVITY_TIMER", NULL);
 	    return TCL_ERROR;
 	}
 	Tk_ResetUserInactiveTime(Tk_Display(tkwin));
@@ -1050,8 +1061,10 @@ Tk_TkwaitObjCmd(
 	     */
 
 	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "window \"", Tcl_GetString(objv[2]),
-		    "\" was deleted before its visibility changed", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "window \"%s\" was deleted before its visibility changed",
+		    Tcl_GetString(objv[2])));
+	    Tcl_SetErrorCode(interp, "TK", "WAIT", "PREMATURE", NULL);
 	    return TCL_ERROR;
 	}
 	Tk_DeleteEventHandler(window,
@@ -1129,8 +1142,7 @@ WaitVisibilityProc(
 
     if (eventPtr->type == VisibilityNotify) {
 	*donePtr = 1;
-    }
-    if (eventPtr->type == DestroyNotify) {
+    } else if (eventPtr->type == DestroyNotify) {
 	*donePtr = 2;
     }
 }
@@ -1584,8 +1596,10 @@ Tk_WinfoObjCmd(
 	}
 	name = Tk_GetAtomName(tkwin, (Atom) id);
 	if (strcmp(name, "?bad atom?") == 0) {
-	    Tcl_AppendResult(interp, "no atom exists with id \"",
-		    Tcl_GetString(objv[2]), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "no atom exists with id \"%s\"", Tcl_GetString(objv[2])));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "ATOM",
+		    Tcl_GetString(objv[2]), NULL);
 	    return TCL_ERROR;
 	}
 	Tcl_SetObjResult(interp, Tcl_NewStringObj(name, -1));
@@ -1643,8 +1657,10 @@ Tk_WinfoObjCmd(
 	winPtr = (TkWindow *) Tk_IdToWindow(Tk_Display(tkwin), id);
 	if ((winPtr == NULL) ||
 		(winPtr->mainPtr != ((TkWindow *) tkwin)->mainPtr)) {
-	    Tcl_AppendResult(interp, "window id \"", string,
-		    "\" doesn't exist in this application", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "window id \"%s\" doesn't exist in this application",
+		    string));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "WINDOW", string, NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1764,8 +1780,9 @@ Tk_WinfoObjCmd(
 	visInfoPtr = XGetVisualInfo(Tk_Display(tkwin), VisualScreenMask,
 		&template, &count);
 	if (visInfoPtr == NULL) {
-	    Tcl_SetResult(interp, "can't find any visuals for screen",
-		    TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't find any visuals for screen", -1));
+	    Tcl_SetErrorCode(interp, "TK", "VISUAL", "NONE", NULL);
 	    return TCL_ERROR;
 	}
 	resultPtr = Tcl_NewObj();
@@ -1860,8 +1877,8 @@ Tk_WmObjCmd(
 	    return TCL_ERROR;
 	}
 	if (objc == 2) {
-	    Tcl_SetObjResult(interp,
-		    Tcl_NewBooleanObj(dispPtr->flags & TK_DISPLAY_WM_TRACING));
+	    Tcl_SetObjResult(interp, Tcl_NewBooleanObj(
+		    dispPtr->flags & TK_DISPLAY_WM_TRACING));
 	    return TCL_OK;
 	}
 	if (Tcl_GetBooleanFromObj(interp, objv[2], &wmTracing) != TCL_OK) {
@@ -1886,8 +1903,10 @@ Tk_WmObjCmd(
 	return TCL_ERROR;
     }
     if (!(winPtr->flags & TK_TOP_LEVEL)) {
-	Tcl_AppendResult(interp, "window \"", winPtr->pathName,
-		"\" isn't a top-level window", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"window \"%s\" isn't a top-level window", winPtr->pathName));
+	Tcl_SetErrorCode(interp, "TK", "LOOKUP", "TOPLEVEL", winPtr->pathName,
+		NULL);
 	return TCL_ERROR;
     }
 
@@ -2058,8 +2077,9 @@ TkGetDisplayOf(
     if ((length >= 2) &&
 	    (strncmp(string, "-displayof", (unsigned) length) == 0)) {
         if (objc < 2) {
-	    Tcl_SetResult(interp, "value for \"-displayof\" missing",
-		    TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "value for \"-displayof\" missing", -1));
+	    Tcl_SetErrorCode(interp, "TK", "NO_VALUE", "DISPLAYOF", NULL);
 	    return -1;
 	}
 	*tkwinPtr = Tk_NameToWindow(interp, Tcl_GetString(objv[1]), *tkwinPtr);
@@ -2097,8 +2117,9 @@ TkDeadAppCmd(
     int argc,			/* Number of arguments. */
     const char **argv)		/* Argument strings. */
 {
-    Tcl_AppendResult(interp, "can't invoke \"", argv[0],
-	    "\" command:  application has been destroyed", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "can't invoke \"%s\" command: application has been destroyed", 
+	    argv[0]));
     return TCL_ERROR;
 }
 
diff --git a/generic/tkColor.c b/generic/tkColor.c
index ea03e28..e4fa3f7 100644
--- a/generic/tkColor.c
+++ b/generic/tkColor.c
@@ -224,11 +224,13 @@ Tk_GetColor(
     if (tkColPtr == NULL) {
 	if (interp != NULL) {
 	    if (*name == '#') {
-		Tcl_AppendResult(interp, "invalid color name \"", name,
-			"\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"invalid color name \"%s\"", name));
+		Tcl_SetErrorCode(interp, "TK", "VALUE", "COLOR", NULL);
 	    } else {
-		Tcl_AppendResult(interp, "unknown color name \"", name,
-			"\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"unknown color name \"%s\"", name));
+		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "COLOR", name, NULL);
 	    }
 	}
 	if (isNew) {
@@ -372,10 +374,12 @@ Tk_NameOfColor(
 	sprintf(tsdPtr->rgbString, "#%04x%04x%04x", colorPtr->red,
 		colorPtr->green, colorPtr->blue);
 
-	/* If the string has the form #RSRSTUTUVWVW (where equal
-	 * letters denote equal hexdigits) then this is
-	 * equivalent to #RSTUVW. Then output the shorter form.
+	/*
+	 * If the string has the form #RSRSTUTUVWVW (where equal letters
+	 * denote equal hexdigits) then this is equivalent to #RSTUVW. Then
+	 * output the shorter form.
 	 */
+
 	if ((tsdPtr->rgbString[1] == tsdPtr->rgbString[3])
 		&& (tsdPtr->rgbString[2] == tsdPtr->rgbString[4])
 		&& (tsdPtr->rgbString[5] == tsdPtr->rgbString[7])
diff --git a/generic/tkConfig.c b/generic/tkConfig.c
index 5262f58..b3e76d2 100644
--- a/generic/tkConfig.c
+++ b/generic/tkConfig.c
@@ -205,7 +205,7 @@ Tk_CreateOptionTable(
     hashEntryPtr = Tcl_CreateHashEntry(hashTablePtr, (char *) templatePtr,
 	    &newEntry);
     if (!newEntry) {
-	tablePtr = (OptionTable *) Tcl_GetHashValue(hashEntryPtr);
+	tablePtr = Tcl_GetHashValue(hashEntryPtr);
 	tablePtr->refCount++;
 	return (Tk_OptionTable) tablePtr;
     }
@@ -391,12 +391,11 @@ DestroyOptionHashTable(
     Tcl_HashTable *hashTablePtr = clientData;
     Tcl_HashSearch search;
     Tcl_HashEntry *hashEntryPtr;
-    OptionTable *tablePtr;
 
     for (hashEntryPtr = Tcl_FirstHashEntry(hashTablePtr, &search);
 	    hashEntryPtr != NULL;
 	    hashEntryPtr = Tcl_NextHashEntry(&search)) {
-	tablePtr = (OptionTable *) Tcl_GetHashValue(hashEntryPtr);
+	OptionTable *tablePtr = Tcl_GetHashValue(hashEntryPtr);
 
 	/*
 	 * The following statements do two tricky things:
@@ -946,16 +945,13 @@ DoObjConfig(
 	break;
     }
 
-    {
-	char buf[40+TCL_INTEGER_SPACE];
-
     default:
-	sprintf(buf, "bad config table: unknown type %d",
-		optionPtr->specPtr->type);
-	Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad config table: unknown type %d",
+		optionPtr->specPtr->type));
+	Tcl_SetErrorCode(interp, "TK", "BAD_CONFIG", NULL);
 	return TCL_ERROR;
     }
-    }
 
     /*
      * Release resources associated with the old value, if we're not returning
@@ -1161,7 +1157,9 @@ GetOptionFromObj(
 
   error:
     if (interp != NULL) {
-	Tcl_AppendResult(interp, "unknown option \"", name, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"unknown option \"%s\"", name));
+	Tcl_SetErrorCode(interp, "TK", "LOOKUP", "OPTION", name, NULL);
     }
     return NULL;
 }
@@ -1228,12 +1226,13 @@ SetOptionFromAny(
     Tcl_Interp *interp,		/* Used for error reporting if not NULL. */
     register Tcl_Obj *objPtr)	/* The object to convert. */
 {
-    Tcl_AppendResult(interp,
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 	    "can't convert value to option except via GetOptionFromObj API",
-	    NULL);
+	    -1));
+    Tcl_SetErrorCode(interp, "TK", "API_ABUSE", NULL);
     return TCL_ERROR;
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -1346,8 +1345,10 @@ Tk_SetOptions(
 
 	if (objc < 2) {
 	    if (interp != NULL) {
-		Tcl_AppendResult(interp, "value for \"",
-			Tcl_GetStringFromObj(*objv, NULL), "\" missing",NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"value for \"%s\" missing",
+			Tcl_GetStringFromObj(*objv, NULL)));
+		Tcl_SetErrorCode(interp, "TK", "VALUE_MISSING", NULL);
 		goto error;
 	    }
 	}
@@ -1369,11 +1370,9 @@ Tk_SetOptions(
 	if (DoObjConfig(interp, recordPtr, optionPtr, objv[1], tkwin,
 		(savePtr != NULL) ? &lastSavePtr->items[lastSavePtr->numItems]
 		: NULL) != TCL_OK) {
-	    char msg[100];
-
-	    sprintf(msg, "\n    (processing \"%.40s\" option)",
-		    Tcl_GetStringFromObj(*objv, NULL));
-	    Tcl_AddErrorInfo(interp, msg);
+	    Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
+		    "\n    (processing \"%.40s\" option)",
+		    Tcl_GetStringFromObj(*objv, NULL)));
 	    goto error;
 	}
 	if (savePtr != NULL) {
@@ -1771,7 +1770,6 @@ FreeResources(
  *	single option or all the configuration options in a table.
  *
  * Results:
-
  *	This function normally returns a pointer to an object. If namePtr
  *	isn't NULL, then the result object is a list with five elements: the
  *	option's name, its database name, database class, default value, and
@@ -2154,8 +2152,7 @@ TkDebugConfig(
     Tcl_Obj *objPtr;
 
     objPtr = Tcl_NewObj();
-    hashTablePtr = (Tcl_HashTable *) Tcl_GetAssocData(interp, OPTION_HASH_KEY,
-	    NULL);
+    hashTablePtr = Tcl_GetAssocData(interp, OPTION_HASH_KEY, NULL);
     if (hashTablePtr == NULL) {
 	return objPtr;
     }
diff --git a/generic/tkConsole.c b/generic/tkConsole.c
index 53f49c1..434350a 100644
--- a/generic/tkConsole.c
+++ b/generic/tkConsole.c
@@ -747,7 +747,9 @@ ConsoleObjCmd(
 	Tcl_SetObjResult(interp, Tcl_GetObjResult(consoleInterp));
 	Tcl_Release(consoleInterp);
     } else {
-	Tcl_AppendResult(interp, "no active console interp", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"no active console interp", -1));
+	Tcl_SetErrorCode(interp, "TK", "CONSOLE", "NONE", NULL);
 	result = TCL_ERROR;
     }
     Tcl_DecrRefCount(cmd);
@@ -796,7 +798,9 @@ InterpreterObjCmd(
     }
 
     if ((otherInterp == NULL) || Tcl_InterpDeleted(otherInterp)) {
-	Tcl_AppendResult(interp, "no active master interp", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"no active master interp", -1));
+	Tcl_SetErrorCode(interp, "TK", "CONSOLE", "NO_INTERP", NULL);
 	return TCL_ERROR;
     }
 
diff --git a/generic/tkCursor.c b/generic/tkCursor.c
index 2bbf861..6b2d5f4 100644
--- a/generic/tkCursor.c
+++ b/generic/tkCursor.c
@@ -352,11 +352,15 @@ Tk_GetCursorFromData(
      */
 
     if (TkParseColor(dataKey.display, Tk_Colormap(tkwin), fg, &fgColor) == 0) {
-	Tcl_AppendResult(interp, "invalid color name \"", fg, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"invalid color name \"%s\"", fg));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "CURSOR", "COLOR", NULL);
 	goto error;
     }
     if (TkParseColor(dataKey.display, Tk_Colormap(tkwin), bg, &bgColor) == 0) {
-	Tcl_AppendResult(interp, "invalid color name \"", bg, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"invalid color name \"%s\"", bg));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "CURSOR", "COLOR", NULL);
 	goto error;
     }
 
diff --git a/generic/tkEntry.c b/generic/tkEntry.c
index 044a35b..d78f396 100644
--- a/generic/tkEntry.c
+++ b/generic/tkEntry.c
@@ -449,8 +449,8 @@ static int		ComputeFormat(Spinbox *sbPtr);
 static const Tk_ClassProcs entryClass = {
     sizeof(Tk_ClassProcs),	/* size */
     EntryWorldChanged,		/* worldChangedProc */
-    NULL,					/* createProc */
-    NULL					/* modalProc */
+    NULL,			/* createProc */
+    NULL			/* modalProc */
 };
 
 /*
@@ -612,6 +612,7 @@ EntryWidgetObjCmd(
     switch ((enum entryCmd) cmdIndex) {
     case COMMAND_BBOX: {
 	int index, x, y, width, height;
+	Tcl_Obj *bbox[4];
 
 	if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 2, objv, "index");
@@ -625,8 +626,11 @@ EntryWidgetObjCmd(
 	    index--;
 	}
 	Tk_CharBbox(entryPtr->textLayout, index, &x, &y, &width, &height);
-	Tcl_SetObjResult(interp, Tcl_ObjPrintf("%d %d %d %d",
-		x + entryPtr->layoutX, y + entryPtr->layoutY, width, height));
+	bbox[0] = Tcl_NewIntObj(x + entryPtr->layoutX);
+	bbox[1] = Tcl_NewIntObj(y + entryPtr->layoutY);
+	bbox[2] = Tcl_NewIntObj(width);
+	bbox[3] = Tcl_NewIntObj(height);
+	Tcl_SetObjResult(interp, Tcl_NewListObj(4, bbox));
 	break;
     }
 
@@ -755,9 +759,11 @@ EntryWidgetObjCmd(
 		&& (strncmp(minorCmd, "dragto", strlen(minorCmd)) == 0)) {
 	    EntryScanTo(entryPtr, x);
 	} else {
-	    Tcl_AppendResult(interp, "bad scan option \"",
-		    Tcl_GetString(objv[2]), "\": must be mark or dragto",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad scan option \"%s\": must be mark or dragto",
+		    minorCmd));
+	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "scan option",
+		    minorCmd, NULL);
 	    goto error;
 	}
 	break;
@@ -851,7 +857,7 @@ EntryWidgetObjCmd(
 		goto error;
 	    }
 	    Tcl_SetObjResult(interp,
-		    Tcl_NewBooleanObj((entryPtr->selectFirst >= 0)));
+		    Tcl_NewBooleanObj(entryPtr->selectFirst >= 0));
 	    goto done;
 
 	case SELECTION_RANGE:
@@ -912,7 +918,7 @@ EntryWidgetObjCmd(
 	if (entryPtr->validate != VALIDATE_NONE) {
 	    entryPtr->validate = selIndex;
 	}
-	Tcl_SetObjResult(interp, Tcl_NewBooleanObj((code == TCL_OK)));
+	Tcl_SetObjResult(interp, Tcl_NewBooleanObj(code == TCL_OK));
 	break;
     }
 
@@ -921,13 +927,12 @@ EntryWidgetObjCmd(
 
 	if (objc == 2) {
 	    double first, last;
-	    char buf[TCL_DOUBLE_SPACE];
+	    Tcl_Obj *span[2];
 
 	    EntryVisibleRange(entryPtr, &first, &last);
-	    Tcl_PrintDouble(NULL, first, buf);
-	    Tcl_SetResult(interp, buf, TCL_VOLATILE);
-	    Tcl_PrintDouble(NULL, last, buf);
-	    Tcl_AppendResult(interp, " ", buf, NULL);
+	    span[0] = Tcl_NewDoubleObj(first);
+	    span[1] = Tcl_NewDoubleObj(last);
+	    Tcl_SetObjResult(interp, Tcl_NewListObj(2, span));
 	    goto done;
 	} else if (objc == 3) {
 	    if (GetEntryIndex(interp, entryPtr, Tcl_GetString(objv[2]),
@@ -1165,9 +1170,11 @@ ConfigureEntry(
 
 	if (entryPtr->type == TK_SPINBOX) {
 	    if (sbPtr->fromValue > sbPtr->toValue) {
-		Tcl_SetResult(interp,
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
 			"-to value must be greater than -from value",
-			TCL_VOLATILE);
+			-1));
+		Tcl_SetErrorCode(interp, "TK", "SPINBOX", "RANGE_SANITY",
+			NULL);
 		continue;
 	    }
 
@@ -1184,9 +1191,12 @@ ConfigureEntry(
 
 		formatLen = strlen(fmt);
 		if ((fmt[0] != '%') || (fmt[formatLen-1] != 'f')) {
-		    badFormatOpt:
-		    Tcl_AppendResult(interp, "bad spinbox format specifier \"",
-			    sbPtr->reqFormat, "\"", NULL);
+		badFormatOpt:
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad spinbox format specifier \"%s\"",
+			    sbPtr->reqFormat));
+		    Tcl_SetErrorCode(interp, "TK", "SPINBOX", "FORMAT_SANITY",
+			    NULL);
 		    continue;
 		}
 		if ((sscanf(fmt, "%%%d.%d%[f]", &min, &max, fbuf) == 3)
@@ -2528,8 +2538,12 @@ GetEntryIndex(
     case 's':
 	if (entryPtr->selectFirst < 0) {
 	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "selection isn't in widget ",
-		    Tk_PathName(entryPtr->tkwin), NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "selection isn't in widget %s",
+		    Tk_PathName(entryPtr->tkwin)));
+	    Tcl_SetErrorCode(interp, "TK",
+		    (entryPtr->type == TK_ENTRY) ? "ENTRY" : "SPINBOX",
+		    "NO_SELECTION", NULL);
 	    return TCL_ERROR;
 	}
 	if (length < 5) {
@@ -2589,6 +2603,9 @@ GetEntryIndex(
   badIndex:
     Tcl_SetObjResult(interp, Tcl_ObjPrintf("bad %s index \"%s\"",
 	    (entryPtr->type == TK_ENTRY) ? "entry" : "spinbox", string));
+    Tcl_SetErrorCode(interp, "TK",
+	    (entryPtr->type == TK_ENTRY) ? "ENTRY" : "SPINBOX",
+	    "BAD_INDEX", NULL);
     return TCL_ERROR;
 }
 
@@ -2935,10 +2952,9 @@ EntryUpdateScrollbar(
     code = Tcl_VarEval(interp, entryPtr->scrollCmd, " ", firstStr, " ",
 	    lastStr, NULL);
     if (code != TCL_OK) {
-	Tcl_AddErrorInfo(interp,
-		"\n    (horizontal scrolling command executed by ");
-	Tcl_AddErrorInfo(interp, Tk_PathName(entryPtr->tkwin));
-	Tcl_AddErrorInfo(interp, ")");
+	Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
+		"\n    (horizontal scrolling command executed by %s)",
+		Tk_PathName(entryPtr->tkwin)));
 	Tcl_BackgroundException(interp, code);
     }
     Tcl_ResetResult(interp);
@@ -3141,7 +3157,7 @@ EntryValidate(
 
     if (code != TCL_OK && code != TCL_RETURN) {
 	Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
-		"\n\t(in validation command executed by %s)",
+		"\n    (in validation command executed by %s)",
 		Tk_PathName(entryPtr->tkwin)));
 	Tcl_BackgroundException(interp, code);
 	return TCL_ERROR;
@@ -3154,7 +3170,7 @@ EntryValidate(
     if (Tcl_GetBooleanFromObj(interp, Tcl_GetObjResult(interp),
 	    &bool) != TCL_OK) {
 	Tcl_AddErrorInfo(interp,
-		 "\nvalid boolean not returned by validation command");
+		 "\n    (invalid boolean result from validation command)");
 	Tcl_BackgroundError(interp);
 	Tcl_ResetResult(interp);
 	return TCL_ERROR;
@@ -3280,7 +3296,7 @@ EntryValidateChange(
 		    TCL_EVAL_GLOBAL | TCL_EVAL_DIRECT);
 	    if (result != TCL_OK) {
 		Tcl_AddErrorInfo(entryPtr->interp,
-			"\n\t(in invalidcommand executed by entry)");
+			"\n    (in invalidcommand executed by entry)");
 		Tcl_BackgroundException(entryPtr->interp, result);
 		code = TCL_ERROR;
 		entryPtr->validate = VALIDATE_NONE;
@@ -3592,7 +3608,7 @@ Tk_SpinboxObjCmd(
 	goto error;
     }
 
-    Tcl_SetResult(interp, Tk_PathName(entryPtr->tkwin), TCL_STATIC);
+    Tcl_SetObjResult(interp, TkNewWindowObj(entryPtr->tkwin));
     return TCL_OK;
 
   error:
@@ -3650,6 +3666,7 @@ SpinboxWidgetObjCmd(
     switch ((enum sbCmd) cmdIndex) {
     case SB_CMD_BBOX: {
 	int index, x, y, width, height;
+	Tcl_Obj *bbox[4];
 
 	if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 2, objv, "index");
@@ -3663,8 +3680,11 @@ SpinboxWidgetObjCmd(
 	    index--;
 	}
 	Tk_CharBbox(entryPtr->textLayout, index, &x, &y, &width, &height);
-	Tcl_SetObjResult(interp, Tcl_ObjPrintf("%d %d %d %d",
-		x + entryPtr->layoutX, y + entryPtr->layoutY, width, height));
+	bbox[0] = Tcl_NewIntObj(x + entryPtr->layoutX);
+	bbox[1] = Tcl_NewIntObj(y + entryPtr->layoutY);
+	bbox[2] = Tcl_NewIntObj(width);
+	bbox[3] = Tcl_NewIntObj(height);
+	Tcl_SetObjResult(interp, Tcl_NewListObj(4, bbox));
 	break;
     }
 
@@ -3830,9 +3850,11 @@ SpinboxWidgetObjCmd(
 		&& (strncmp(minorCmd, "dragto", strlen(minorCmd)) == 0)) {
 	    EntryScanTo(entryPtr, x);
 	} else {
-	    Tcl_AppendResult(interp, "bad scan option \"",
-		    Tcl_GetString(objv[2]), "\": must be mark or dragto",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad scan option \"%s\": must be mark or dragto",
+		    minorCmd));
+	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "scan option",
+		    minorCmd, NULL);
 	    goto error;
 	}
 	break;
@@ -3925,8 +3947,8 @@ SpinboxWidgetObjCmd(
 		Tcl_WrongNumArgs(interp, 3, objv, NULL);
 		goto error;
 	    }
-	    Tcl_SetObjResult(interp,
-		    Tcl_NewBooleanObj((entryPtr->selectFirst >= 0)));
+	    Tcl_SetObjResult(interp, Tcl_NewBooleanObj(
+		    entryPtr->selectFirst >= 0));
 	    goto done;
 
 	case SB_SEL_RANGE:
@@ -4030,13 +4052,12 @@ SpinboxWidgetObjCmd(
 
 	if (objc == 2) {
 	    double first, last;
-	    char buf[TCL_DOUBLE_SPACE];
+	    Tcl_Obj *span[2];
 
 	    EntryVisibleRange(entryPtr, &first, &last);
-	    Tcl_PrintDouble(NULL, first, buf);
-	    Tcl_SetResult(interp, buf, TCL_VOLATILE);
-	    Tcl_PrintDouble(NULL, last, buf);
-	    Tcl_AppendResult(interp, " ", buf, NULL);
+	    span[0] = Tcl_NewDoubleObj(first);
+	    span[1] = Tcl_NewDoubleObj(last);
+	    Tcl_SetObjResult(interp, Tcl_NewListObj(2, span));
 	    goto done;
 	} else if (objc == 3) {
 	    if (GetEntryIndex(interp, entryPtr, Tcl_GetString(objv[2]),
@@ -4284,7 +4305,8 @@ SpinboxInvoke(
 	Tcl_DStringFree(&script);
 
 	if (code != TCL_OK) {
-	    Tcl_AddErrorInfo(interp, "\n\t(in command executed by spinbox)");
+	    Tcl_AddErrorInfo(interp,
+		    "\n    (in command executed by spinbox)");
 	    Tcl_BackgroundException(interp, code);
 
 	    /*
diff --git a/generic/tkEvent.c b/generic/tkEvent.c
index 1fbf1dd..463379a 100644
--- a/generic/tkEvent.c
+++ b/generic/tkEvent.c
@@ -1336,7 +1336,7 @@ Tk_HandleEvent(
 	}
     } else {
 	for (handlerPtr = winPtr->handlerList; handlerPtr != NULL; ) {
-	    if ((handlerPtr->mask & mask) != 0) {
+	    if (handlerPtr->mask & mask) {
 		ip.nextHandler = handlerPtr->nextPtr;
 		handlerPtr->proc(handlerPtr->clientData, eventPtr);
 		handlerPtr = ip.nextHandler;
diff --git a/generic/tkFileFilter.c b/generic/tkFileFilter.c
index fba570b..8588d70 100644
--- a/generic/tkFileFilter.c
+++ b/generic/tkFileFilter.c
@@ -120,10 +120,12 @@ TkGetFileFilters(
 	}
 
 	if (count != 2 && count != 3) {
-	    Tcl_AppendResult(interp, "bad file type \"",
-		    Tcl_GetString(listObjv[i]), "\", ",
-		    "should be \"typeName {extension ?extensions ...?} ",
-		    "?{macType ?macTypes ...?}?\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad file type \"%s\", should be "
+		    "\"typeName {extension ?extensions ...?} "
+		    "?{macType ?macTypes ...?}?\"",
+		    Tcl_GetString(listObjv[i])));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "FILE_TYPE", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -289,8 +291,10 @@ AddClause(
 		Tcl_DStringFree(&osTypeDS);
 	    }
 	    if (len != 4) {
-		Tcl_AppendResult(interp, "bad Macintosh file type \"",
-			Tcl_GetString(ostypeList[i]), "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"bad Macintosh file type \"%s\"",
+			Tcl_GetString(ostypeList[i])));
+		Tcl_SetErrorCode(interp, "TK", "VALUE", "MAC_TYPE", NULL);
 		code = TCL_ERROR;
 		goto done;
 	    }
diff --git a/generic/tkFocus.c b/generic/tkFocus.c
index 2f50009..b5e2edf 100644
--- a/generic/tkFocus.c
+++ b/generic/tkFocus.c
@@ -115,7 +115,7 @@ Tk_FocusObjCmd(
     };
     Tk_Window tkwin = clientData;
     TkWindow *winPtr = clientData;
-    TkWindow *newPtr, *focusWinPtr, *topLevelPtr;
+    TkWindow *newPtr, *topLevelPtr;
     ToplevelFocusInfo *tlFocusPtr;
     const char *windowName;
     int index;
@@ -125,9 +125,10 @@ Tk_FocusObjCmd(
      */
 
     if (objc == 1) {
-	focusWinPtr = TkGetFocusWin(winPtr);
-	if (focusWinPtr != NULL) {
-	    Tcl_SetResult(interp, focusWinPtr->pathName, TCL_STATIC);
+	Tk_Window focusWin = (Tk_Window) TkGetFocusWin(winPtr);
+
+	if (focusWin != NULL) {
+	    Tcl_SetObjResult(interp, TkNewWindowObj(focusWin));
 	}
 	return TCL_OK;
     }
@@ -180,7 +181,7 @@ Tk_FocusObjCmd(
 	}
 	newPtr = TkGetFocusWin(newPtr);
 	if (newPtr != NULL) {
-	    Tcl_SetResult(interp, newPtr->pathName, TCL_STATIC);
+	    Tcl_SetObjResult(interp, TkNewWindowObj((Tk_Window) newPtr));
 	}
 	break;
     case 1:			/* -force */
@@ -213,12 +214,12 @@ Tk_FocusObjCmd(
 	    for (tlFocusPtr = newPtr->mainPtr->tlFocusPtr; tlFocusPtr != NULL;
 		    tlFocusPtr = tlFocusPtr->nextPtr) {
 		if (tlFocusPtr->topLevelPtr == topLevelPtr) {
-		    Tcl_SetResult(interp,
-			    tlFocusPtr->focusWinPtr->pathName, TCL_STATIC);
+		    Tcl_SetObjResult(interp, TkNewWindowObj((Tk_Window)
+			    tlFocusPtr->focusWinPtr));
 		    return TCL_OK;
 		}
 	    }
-	    Tcl_SetResult(interp, topLevelPtr->pathName, TCL_STATIC);
+	    Tcl_SetObjResult(interp, TkNewWindowObj((Tk_Window) topLevelPtr));
 	    return TCL_OK;
 	}
 	break;
diff --git a/generic/tkFont.c b/generic/tkFont.c
index 32d0589..4485df8 100644
--- a/generic/tkFont.c
+++ b/generic/tkFont.c
@@ -439,7 +439,7 @@ TkFontPkgFree(
 	hPtr = Tcl_NextHashEntry(&search);
     }
     Tcl_DeleteHashTable(&fiPtr->namedTable);
-    if (fiPtr->updatePending != 0) {
+    if (fiPtr->updatePending) {
 	Tcl_CancelIdleCall(TheWorldHasChanged, fiPtr);
     }
     ckfree(fiPtr);
@@ -569,6 +569,7 @@ Tk_FontObjCmd(
 			-1, 40, "...");
 		Tcl_AppendToObj(resultPtr, "\"", -1);
 		Tcl_SetObjResult(interp, resultPtr);
+		Tcl_SetErrorCode(interp, "TK", "VALUE", "FONT_SAMPLE", NULL);
 		return TCL_ERROR;
 	    }
 	    uniChar = Tcl_GetUniChar(charPtr, 0);
@@ -615,9 +616,10 @@ Tk_FontObjCmd(
 	if (namedHashPtr != NULL) {
 	    nfPtr = Tcl_GetHashValue(namedHashPtr);
 	}
-	if ((namedHashPtr == NULL) || (nfPtr->deletePending != 0)) {
-	    Tcl_AppendResult(interp, "named font \"", string,
-		    "\" doesn't exist", NULL);
+	if ((namedHashPtr == NULL) || nfPtr->deletePending) {
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "named font \"%s\" doesn't exist", string));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "FONT", string, NULL);
 	    return TCL_ERROR;
 	}
 	if (objc == 3) {
@@ -670,7 +672,7 @@ Tk_FontObjCmd(
 	if (TkCreateNamedFont(interp, tkwin, name, &fa) != TCL_OK) {
 	    return TCL_ERROR;
 	}
-	Tcl_AppendResult(interp, name, NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(name, -1));
 	break;
     }
     case FONT_DELETE: {
@@ -686,7 +688,7 @@ Tk_FontObjCmd(
 	    Tcl_WrongNumArgs(interp, 2, objv, "fontname ?fontname ...?");
 	    return TCL_ERROR;
 	}
-	for (i = 2; i < objc && result == TCL_OK; i++) {
+	for (i = 2; (i < objc) && (result == TCL_OK); i++) {
 	    string = Tcl_GetString(objv[i]);
 	    result = TkDeleteNamedFont(interp, tkwin, string);
 	}
@@ -726,8 +728,8 @@ Tk_FontObjCmd(
 	    return TCL_ERROR;
 	}
 	string = Tcl_GetStringFromObj(objv[3 + skip], &length);
-	Tcl_SetObjResult(interp,
-		Tcl_NewIntObj(Tk_TextWidth(tkfont, string, length)));
+	Tcl_SetObjResult(interp, Tcl_NewIntObj(
+		Tk_TextWidth(tkfont, string, length)));
 	Tk_FreeFont(tkfont);
 	break;
     }
@@ -792,7 +794,7 @@ Tk_FontObjCmd(
 	while (namedHashPtr != NULL) {
 	    NamedFont *nfPtr = Tcl_GetHashValue(namedHashPtr);
 
-	    if (nfPtr->deletePending == 0) {
+	    if (!nfPtr->deletePending) {
 		char *string = Tcl_GetHashKey(&fiPtr->namedTable,
 			namedHashPtr);
 
@@ -853,7 +855,7 @@ UpdateDependentFonts(
 		fontPtr != NULL; fontPtr = fontPtr->nextPtr) {
 	    if (fontPtr->namedHashPtr == namedHashPtr) {
 		TkpGetFontFromAttributes(fontPtr, tkwin, &nfPtr->fa);
-		if (fiPtr->updatePending == 0) {
+		if (!fiPtr->updatePending) {
 		    fiPtr->updatePending = 1;
 		    Tcl_DoWhenIdle(TheWorldHasChanged, fiPtr);
 		}
@@ -947,10 +949,11 @@ TkCreateNamedFont(
     namedHashPtr = Tcl_CreateHashEntry(&fiPtr->namedTable, name, &isNew);
     if (!isNew) {
 	nfPtr = Tcl_GetHashValue(namedHashPtr);
-	if (nfPtr->deletePending == 0) {
+	if (!nfPtr->deletePending) {
 	    if (interp) {
-		Tcl_AppendResult(interp, "named font \"", name,
-			"\" already exists", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"named font \"%s\" already exists", name));
+		Tcl_SetErrorCode(interp, "TK", "FONT", "EXISTS", NULL);
 	    }
 	    return TCL_ERROR;
 	}
@@ -1000,8 +1003,9 @@ TkDeleteNamedFont(
     namedHashPtr = Tcl_FindHashEntry(&fiPtr->namedTable, name);
     if (namedHashPtr == NULL) {
 	if (interp) {
-	    Tcl_AppendResult(interp, "named font \"", name,
-		    "\" doesn't exist", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "named font \"%s\" doesn't exist", name));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "FONT", name, NULL);
 	}
 	return TCL_ERROR;
     }
@@ -1183,8 +1187,10 @@ Tk_AllocFontFromObj(
 	if (isNew) {
 	    Tcl_DeleteHashEntry(cacheHashPtr);
 	}
-	Tcl_AppendResult(interp, "failed to allocate font due to ",
-		"internal system font engine problem", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"failed to allocate font due to internal system font engine"
+		" problem", -1));
+	Tcl_SetErrorCode(interp, "TK", "FONT", "INTERNAL_PROBLEM", NULL);
 	return NULL;
     }
 
@@ -1421,7 +1427,7 @@ Tk_FreeFont(
 
 	nfPtr = Tcl_GetHashValue(fontPtr->namedHashPtr);
 	nfPtr->refCount--;
-	if ((nfPtr->refCount == 0) && (nfPtr->deletePending != 0)) {
+	if ((nfPtr->refCount == 0) && nfPtr->deletePending) {
 	    Tcl_DeleteHashEntry(fontPtr->namedHashPtr);
 	    ckfree(nfPtr);
 	}
@@ -1749,7 +1755,7 @@ Tk_PostscriptFontName(
 
     slantString = NULL;
     if (fontPtr->fa.slant == TK_FS_ROMAN) {
-	;
+	/* Do nothing */
     } else if ((strcmp(family, "Helvetica") == 0)
 	    || (strcmp(family, "Courier") == 0)
 	    || (strcmp(family, "AvantGarde") == 0)) {
@@ -2137,7 +2143,7 @@ Tk_ComputeTextLayout(
      * on the next line. Otherwise "Hello" and "Hello\n" are the same height.
      */
 
-    if ((layoutPtr->numChunks > 0) && ((flags & TK_IGNORE_NEWLINES) == 0)) {
+    if ((layoutPtr->numChunks > 0) && !(flags & TK_IGNORE_NEWLINES)) {
 	if (layoutPtr->chunks[layoutPtr->numChunks - 1].start[0] == '\n') {
 	    chunkPtr = NewChunk(&layoutPtr, &maxChunks, start, 0, curX,
 		    curX, baseline);
@@ -2899,7 +2905,7 @@ Tk_IntersectTextLayout(
 
     result = 0;
     for (i = 0; i < layoutPtr->numChunks; i++) {
-	if ((chunkPtr->start[0] == '\n') || (chunkPtr->numBytes==0)) {
+	if ((chunkPtr->start[0] == '\n') || (chunkPtr->numBytes == 0)) {
 	    /*
 	     * Newline characters and empty chunks are not counted when
 	     * computing area intersection (but tab characters would still be
@@ -3235,121 +3241,92 @@ Tk_TextLayoutToPostscript(
     Tk_TextLayout layout)	/* The layout to be rendered. */
 {
     TextLayout *layoutPtr = (TextLayout *) layout;
-#define MAXUSE 128
-    char buf[MAXUSE+30];
-    LayoutChunk *chunkPtr;
-    int i, j, used, baseline, charsize;
-    Tcl_UniChar ch;
+    LayoutChunk *chunkPtr = layoutPtr->chunks;
+    int baseline = chunkPtr->y;
+    Tcl_Obj *psObj = Tcl_NewObj();
+    int i, j, len;
     const char *p, *glyphname;
+    char uindex[5], c, *ps;
+    Tcl_UniChar ch;
 
-    chunkPtr = layoutPtr->chunks;
-    baseline = chunkPtr->y;
-    used = 0;
-    buf[used++] = '[';
-    buf[used++] = '(';
-    for (i = 0; i < layoutPtr->numChunks; i++) {
+    Tcl_AppendToObj(psObj, "[(", -1);
+    for (i = 0; i < layoutPtr->numChunks; i++, chunkPtr++) {
 	if (baseline != chunkPtr->y) {
-	    buf[used++] = ')';
-	    buf[used++] = ']';
-	    buf[used++] = '\n';
-	    buf[used++] = '[';
-	    buf[used++] = '(';
+	    Tcl_AppendToObj(psObj, ")]\n[(", -1);
 	    baseline = chunkPtr->y;
 	}
 	if (chunkPtr->numDisplayChars <= 0) {
 	    if (chunkPtr->start[0] == '\t') {
-		buf[used++] = '\\';
-		buf[used++] = 't';
+		Tcl_AppendToObj(psObj, "\\t", -1);
 	    }
-	} else {
-	    p = chunkPtr->start;
-	    for (j = 0; j < chunkPtr->numDisplayChars; j++) {
+	    continue;
+	}
+
+	for (p=chunkPtr->start, j=0; j<chunkPtr->numDisplayChars; j++) {
+	    /*
+	     * INTL: We only handle symbols that have an encoding as a glyph
+	     * from the standard set defined by Adobe. The rest get punted.
+	     * Eventually this should be revised to handle more sophsticiated
+	     * international postscript fonts.
+	     */
+
+	    p += Tcl_UtfToUniChar(p, &ch);
+	    if ((ch == '(') || (ch == ')') || (ch == '\\') || (ch < 0x20)) {
 		/*
-		 * INTL: We only handle symbols that have an encoding as a
-		 * flyph from the standard set defined by Adobe. The rest get
-		 * punted. Eventually this should be revised to handle more
-		 * sophsticiated international postscript fonts.
+		 * Tricky point: the "03" is necessary in the sprintf below,
+		 * so that a full three digits of octal are always generated.
+		 * Without the "03", a number following this sequence could be
+		 * interpreted by Postscript as part of this sequence.
 		 */
 
-		charsize = Tcl_UtfToUniChar(p, &ch);
-		p += charsize;
-
-		if ((ch == '(') || (ch == ')') || (ch == '\\')
-			|| (ch < 0x20)) {
-		    /*
-		     * Tricky point: the "03" is necessary in the sprintf
-		     * below, so that a full three digits of octal are always
-		     * generated. Without the "03", a number following this
-		     * sequence could be interpreted by Postscript as part of
-		     * this sequence.
-		     */
+		Tcl_AppendPrintfToObj(psObj, "\\%03o", ch);
+		continue;
+	    } else if (ch <= 0x7f) {
+		/*
+		 * Normal ASCII character.
+		 */
 
-		    sprintf(buf + used, "\\%03o", ch);
-		    used += 4;
-		} else if (ch <= 0x7f) {
-		    /*
-		     * Normal ASCII character.
-		     */
+		c = (char) ch;
+		Tcl_AppendToObj(psObj, &c, 1);
+		continue;
+	    }
 
-		    buf[used++] = (char) ch;
-		} else {
-		    char uindex[5];
+	    /*
+	     * This character doesn't belong to the ASCII character set, so we
+	     * use the full glyph name.
+	     */
 
+	    sprintf(uindex, "%04X", ch);		/* endianness? */
+	    glyphname = Tcl_GetVar2(interp, "::tk::psglyphs", uindex, 0);
+	    if (glyphname) {
+		ps = Tcl_GetStringFromObj(psObj, &len);
+		if (ps[len-1] == '(') {
 		    /*
-		     * This character doesn't belong to the ASCII character
-		     * set, so we use the full glyph name.
+		     * In-place edit. Ewww!
 		     */
 
-		    sprintf(uindex, "%04X", ch);	/* endianness? */
-		    glyphname = Tcl_GetVar2(interp, "::tk::psglyphs", uindex,
-			    0);
-		    if (glyphname) {
-			if (used > 0 && buf[used-1] == '(') {
-			    used--;
-			} else {
-			    buf[used++] = ')';
-			}
-			buf[used++] = '/';
-			while ((*glyphname) && (used < MAXUSE+27)) {
-			    buf[used++] = *glyphname++;
-			}
-			buf[used++] = '(';
-		    } else {
-			/*
-			 * No known mapping for the character into the space
-			 * of PostScript glyphs. Ignore it. :-(
-			 */
+		    ps[len-1] = '/';
+		} else {
+		    Tcl_AppendToObj(psObj, ")/", -1);
+		}
+		Tcl_AppendToObj(psObj, glyphname, -1);
+		Tcl_AppendToObj(psObj, "(", -1);
+	    } else {
+		/*
+		 * No known mapping for the character into the space of
+		 * PostScript glyphs. Ignore it. :-(
+		 */
 
 #ifdef TK_DEBUG_POSTSCRIPT_OUTPUT
-			fprintf(stderr, "Warning: no mapping to PostScript "
-				"glyphs for \\u%04x\n", ch);
+		fprintf(stderr, "Warning: no mapping to PostScript "
+			"glyphs for \\u%04x\n", ch);
 #endif
-		    }
-		}
-		if (used >= MAXUSE) {
-		    buf[used] = '\0';
-		    Tcl_AppendResult(interp, buf, NULL);
-		    used = 0;
-		}
 	    }
 	}
-	if (used >= MAXUSE) {
-	    /*
-	     * If there are a whole bunch of returns or tabs in a row, then
-	     * buf[] could get filled up.
-	     */
-
-	    buf[used] = '\0';
-	    Tcl_AppendResult(interp, buf, NULL);
-	    used = 0;
-	}
-	chunkPtr++;
     }
-    buf[used++] = ')';
-    buf[used++] = ']';
-    buf[used++] = '\n';
-    buf[used] = '\0';
-    Tcl_AppendResult(interp, buf, NULL);
+    Tcl_AppendToObj(psObj, ")]\n", -1);
+    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    Tcl_DecrRefCount(psObj);
 }
 
 /*
@@ -3403,8 +3380,10 @@ ConfigAttributesObj(
 	     */
 
 	    if (interp != NULL) {
-		Tcl_AppendResult(interp, "value for \"",
-			Tcl_GetString(optionPtr), "\" option missing", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"value for \"%s\" option missing",
+			Tcl_GetString(optionPtr)));
+		Tcl_SetErrorCode(interp, "TK", "FONT", "NO_ATTRIBUTE", NULL);
 	    }
 	    return TCL_ERROR;
 	}
@@ -3598,7 +3577,7 @@ ParseFontNameObj(
 	}
 	dash = strchr(string + 1, '-');
 	if ((dash != NULL)
-		&& (!isspace(UCHAR(dash[-1])))) { /* INTL: ISO space */
+		&& !isspace(UCHAR(dash[-1]))) {	/* INTL: ISO space */
 	    goto xlfd;
 	}
 
@@ -3646,8 +3625,9 @@ ParseFontNameObj(
     if ((Tcl_ListObjGetElements(NULL, objPtr, &objc, &objv) != TCL_OK)
 	    || (objc < 1)) {
 	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "font \"", string, "\" doesn't exist",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "font \"%s\" doesn't exist", string));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "FONT", string, NULL);
 	}
 	return TCL_ERROR;
     }
@@ -3694,8 +3674,10 @@ ParseFontNameObj(
 	 */
 
 	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "unknown font style \"",
-		    Tcl_GetString(objv[i]), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "unknown font style \"%s\"", Tcl_GetString(objv[i])));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "FONT_STYLE",
+		    Tcl_GetString(objv[i]), NULL);
 	}
 	return TCL_ERROR;
     }
@@ -3848,7 +3830,7 @@ TkFontParseXLFD(
      * parsed set of attributes)".
      */
 
-    if ((i > XLFD_ADD_STYLE) && (FieldSpecified(field[XLFD_ADD_STYLE]))) {
+    if ((i > XLFD_ADD_STYLE) && FieldSpecified(field[XLFD_ADD_STYLE])) {
 	if (atoi(field[XLFD_ADD_STYLE]) != 0) {
 	    for (j = XLFD_NUMFIELDS - 1; j >= XLFD_ADD_STYLE; j--) {
 		field[j + 1] = field[j];
@@ -4077,7 +4059,6 @@ TkFontGetPoints(
  *	platform expects when asking for the font.
  *
  * Results:
-
  *	As above. The return value is NULL if the font name has no aliases.
  *
  * Side effects:
@@ -4247,12 +4228,11 @@ TkFontGetFirstTextLayout(
     Tk_Font *font,
     char *dst)
 {
-    TextLayout *layoutPtr;
+    TextLayout *layoutPtr = (TextLayout *) layout;
     LayoutChunk *chunkPtr;
     int numBytesInChunk;
 
-    layoutPtr = (TextLayout *) layout;
-    if ((layoutPtr==NULL) || (layoutPtr->numChunks==0)
+    if ((layoutPtr == NULL) || (layoutPtr->numChunks == 0)
 	    || (layoutPtr->chunks->numDisplayChars <= 0)) {
 	dst[0] = '\0';
 	return 0;
diff --git a/generic/tkFrame.c b/generic/tkFrame.c
index 55f5d51..8bc44ce 100644
--- a/generic/tkFrame.c
+++ b/generic/tkFrame.c
@@ -334,8 +334,8 @@ static void		MapFrame(ClientData clientData);
 static const Tk_ClassProcs frameClass = {
     sizeof(Tk_ClassProcs),	/* size */
     FrameWorldChanged,		/* worldChangedProc */
-    NULL,					/* createProc */
-    NULL					/* modalProc */
+    NULL,			/* createProc */
+    NULL			/* modalProc */
 };
 
 /*
@@ -465,7 +465,7 @@ CreateFrame(
     Tk_Window newWin;
     const char *className, *screenName, *visualName, *colormapName;
     const char *arg, *useOption;
-    int i, c, length, depth;
+    int i, length, depth;
     unsigned int mask;
     Colormap colormap;
     Visual *visual;
@@ -496,20 +496,19 @@ CreateFrame(
 	if (length < 2) {
 	    continue;
 	}
-	c = arg[1];
-	if ((c == 'c') && (length >= 3)
+	if ((arg[1] == 'c') && (length >= 3)
 		&& (strncmp(arg, "-class", (unsigned) length) == 0)) {
 	    className = Tcl_GetString(objv[i+1]);
-	} else if ((c == 'c')
+	} else if ((arg[1] == 'c') && (length >= 3)
 		&& (strncmp(arg, "-colormap", (unsigned) length) == 0)) {
 	    colormapName = Tcl_GetString(objv[i+1]);
-	} else if ((c == 's') && (type == TYPE_TOPLEVEL)
+	} else if ((arg[1] == 's') && (type == TYPE_TOPLEVEL)
 		&& (strncmp(arg, "-screen", (unsigned) length) == 0)) {
 	    screenName = Tcl_GetString(objv[i+1]);
-	} else if ((c == 'u') && (type == TYPE_TOPLEVEL)
+	} else if ((arg[1] == 'u') && (type == TYPE_TOPLEVEL)
 		&& (strncmp(arg, "-use", (unsigned) length) == 0)) {
 	    useOption = Tcl_GetString(objv[i+1]);
-	} else if ((c == 'v')
+	} else if ((arg[1] == 'v')
 		&& (strncmp(arg, "-visual", (unsigned) length) == 0)) {
 	    visualName = Tcl_GetString(objv[i+1]);
 	}
@@ -548,9 +547,10 @@ CreateFrame(
 	 * are being destroyed. Let an error be thrown.
 	 */
 
-	Tcl_AppendResult(interp, "unable to create widget \"",
-		Tcl_GetString(objv[1]), "\"", NULL);
-	newWin = NULL;
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"unable to create widget \"%s\"", Tcl_GetString(objv[1])));
+	Tcl_SetErrorCode(interp, "TK", "APPLICATION_GONE", NULL);
+	return TCL_ERROR;
     } else {
 	/*
 	 * We were called from Tk_Init; create a new application.
@@ -560,13 +560,14 @@ CreateFrame(
     }
     if (newWin == NULL) {
 	goto error;
-    } else {
-	/*
-	 * Mark Tk frames as suitable candidates for [wm manage]
-	 */
-	TkWindow *winPtr = (TkWindow *)newWin;
-	winPtr->flags |= TK_WM_MANAGEABLE;
     }
+
+    /*
+     * Mark Tk frames as suitable candidates for [wm manage].
+     */
+
+    ((TkWindow *) newWin)->flags |= TK_WM_MANAGEABLE;
+
     if (className == NULL) {
 	className = Tk_GetOption(newWin, "class", "Class");
 	if (className == NULL) {
@@ -577,10 +578,9 @@ CreateFrame(
     if (useOption == NULL) {
 	useOption = Tk_GetOption(newWin, "use", "Use");
     }
-    if ((useOption != NULL) && (*useOption != 0)) {
-	if (TkpUseWindow(interp, newWin, useOption) != TCL_OK) {
-	    goto error;
-	}
+    if ((useOption != NULL) && (*useOption != 0)
+	    && (TkpUseWindow(interp, newWin, useOption) != TCL_OK)) {
+	goto error;
     }
     if (visualName == NULL) {
 	visualName = Tk_GetOption(newWin, "visual", "Visual");
@@ -630,12 +630,11 @@ CreateFrame(
 	framePtr = ckalloc(sizeof(Frame));
 	memset(framePtr, 0, sizeof(Frame));
     }
-    framePtr->tkwin		= newWin;
-    framePtr->display		= Tk_Display(newWin);
-    framePtr->interp		= interp;
-    framePtr->widgetCmd		= Tcl_CreateObjCommand(interp,
-	    Tk_PathName(newWin), FrameWidgetObjCmd, framePtr,
-	    FrameCmdDeletedProc);
+    framePtr->tkwin = newWin;
+    framePtr->display = Tk_Display(newWin);
+    framePtr->interp = interp;
+    framePtr->widgetCmd	= Tcl_CreateObjCommand(interp, Tk_PathName(newWin),
+	    FrameWidgetObjCmd, framePtr, FrameCmdDeletedProc);
     framePtr->optionTable = optionTable;
     framePtr->type = type;
     framePtr->colormap = colormap;
@@ -665,14 +664,15 @@ CreateFrame(
 	    (ConfigureFrame(interp, framePtr, objc-2, objv+2) != TCL_OK)) {
 	goto error;
     }
-    if ((framePtr->isContainer)) {
-	if (framePtr->useThis == NULL) {
-	    TkpMakeContainer(framePtr->tkwin);
-	} else {
-	    Tcl_AppendResult(interp, "A window cannot have both the -use ",
-		    "and the -container option set.", NULL);
+    if (framePtr->isContainer) {
+	if (framePtr->useThis != NULL) {
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "windows cannot have both the -use and the -container"
+		    " option set", -1));
+	    Tcl_SetErrorCode(interp, "TK", "FRAME", "CONTAINMENT", NULL);
 	    goto error;
 	}
+	TkpMakeContainer(framePtr->tkwin);
     }
     if (type == TYPE_TOPLEVEL) {
 	Tcl_DoWhenIdle(MapFrame, framePtr);
@@ -765,6 +765,7 @@ FrameWidgetObjCmd(
 
 	    for (i = 2; i < objc; i++) {
 		const char *arg = Tcl_GetStringFromObj(objv[i], &length);
+
 		if (length < 2) {
 		    continue;
 		}
@@ -785,23 +786,22 @@ FrameWidgetObjCmd(
 #ifdef SUPPORT_CONFIG_EMBEDDED
 		    if (c == 'u') {
 			const char *string = Tcl_GetString(objv[i+1]);
+
 			if (TkpUseWindow(interp, framePtr->tkwin,
 				string) != TCL_OK) {
 			    result = TCL_ERROR;
 			    goto done;
 			}
-		    } else {
-			Tcl_AppendResult(interp, "can't modify ", arg,
-				" option after widget is created", NULL);
-			result = TCL_ERROR;
-			goto done;
+			continue;
 		    }
-#else
-			Tcl_AppendResult(interp, "can't modify ", arg,
-				" option after widget is created", NULL);
-			result = TCL_ERROR;
-			goto done;
 #endif
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "can't modify %s option after widget is created",
+			    arg));
+		    Tcl_SetErrorCode(interp, "TK", "FRAME", "CREATE_ONLY",
+			    NULL);
+		    result = TCL_ERROR;
+		    goto done;
 		}
 	    }
 	    result = ConfigureFrame(interp, framePtr, objc-2, objv+2);
@@ -1011,19 +1011,14 @@ ConfigureFrame(
 		    }
 		    sibling = ancestor;
 		    if (Tk_IsTopLevel(ancestor)) {
-		    badWindow:
-			Tcl_AppendResult(interp, "can't use ",
-				Tk_PathName(labelframePtr->labelWin),
-				" as label in this frame", NULL);
-			labelframePtr->labelWin = NULL;
-			return TCL_ERROR;
+			goto badLabelWindow;
 		    }
 		}
 		if (Tk_IsTopLevel(labelframePtr->labelWin)) {
-		    goto badWindow;
+		    goto badLabelWindow;
 		}
 		if (labelframePtr->labelWin == framePtr->tkwin) {
-		    goto badWindow;
+		    goto badLabelWindow;
 		}
 		Tk_CreateEventHandler(labelframePtr->labelWin,
 			StructureNotifyMask, FrameStructureProc, framePtr);
@@ -1044,6 +1039,14 @@ ConfigureFrame(
 
     FrameWorldChanged(framePtr);
     return TCL_OK;
+
+  badLabelWindow:
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "can't use %s as label in this frame",
+	    Tk_PathName(labelframePtr->labelWin)));
+    Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "HIERARCHY", NULL);
+    labelframePtr->labelWin = NULL;
+    return TCL_ERROR;
 }
 
 /*
diff --git a/generic/tkGeometry.c b/generic/tkGeometry.c
index 2c6c113..2e0009a 100644
--- a/generic/tkGeometry.c
+++ b/generic/tkGeometry.c
@@ -321,7 +321,8 @@ Tk_SetMinimumRequestSize(
 int
 TkSetGeometryMaster(
     Tcl_Interp *interp,		/* Current interpreter, for error. */
-    Tk_Window tkwin,		/* Window that will have geometry master set. */
+    Tk_Window tkwin,		/* Window that will have geometry master
+				 * set. */
     const char *master)		/* The master identity. */
 {
     register TkWindow *winPtr = (TkWindow *) tkwin;
@@ -332,10 +333,11 @@ TkSetGeometryMaster(
     }
     if (winPtr->geometryMaster != NULL) {
 	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "cannot use geometry manager ", master,
-		    " inside ", Tk_PathName(tkwin),
-  	            " which already has slaves managed by ",
-		    winPtr->geometryMaster, NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "cannot use geometry manager %s inside %s which already"
+		    " has slaves managed by %s",
+		    master, Tk_PathName(tkwin), winPtr->geometryMaster));
+	    Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "FIGHT", NULL);
 	}
 	return TCL_ERROR;
     }
@@ -364,8 +366,9 @@ TkSetGeometryMaster(
 
 void
 TkFreeGeometryMaster(
-    Tk_Window tkwin,	/* Window that will have geometry master cleared. */
-    const char *master)	/* The master identity. */
+    Tk_Window tkwin,		/* Window that will have geometry master
+				 * cleared. */
+    const char *master)		/* The master identity. */
 {
     register TkWindow *winPtr = (TkWindow *) tkwin;
 
diff --git a/generic/tkGet.c b/generic/tkGet.c
index bd63971..d58b4a5 100644
--- a/generic/tkGet.c
+++ b/generic/tkGet.c
@@ -152,8 +152,10 @@ Tk_GetAnchor(
     }
 
   error:
-    Tcl_AppendResult(interp, "bad anchor position \"", string,
-	    "\": must be n, ne, e, se, s, sw, w, nw, or center", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad anchor position \"%s\": must be"
+	    " n, ne, e, se, s, sw, w, nw, or center", string));
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "ANCHOR", NULL);
     return TCL_ERROR;
 }
 
@@ -237,8 +239,10 @@ Tk_GetJoinStyle(
 	return TCL_OK;
     }
 
-    Tcl_AppendResult(interp, "bad join style \"", string,
-	    "\": must be bevel, miter, or round", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad join style \"%s\": must be bevel, miter, or round",
+	    string));
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "JOIN", NULL);
     return TCL_ERROR;
 }
 
@@ -316,8 +320,10 @@ Tk_GetCapStyle(
 	return TCL_OK;
     }
 
-    Tcl_AppendResult(interp, "bad cap style \"", string,
-	    "\": must be butt, projecting, or round", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad cap style \"%s\": must be butt, projecting, or round",
+	    string));
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "CAP", NULL);
     return TCL_ERROR;
 }
 
@@ -432,8 +438,10 @@ Tk_GetJustify(
 	return TCL_OK;
     }
 
-    Tcl_AppendResult(interp, "bad justification \"", string,
-	    "\": must be left, right, or center", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad justification \"%s\": must be left, right, or center",
+	    string));
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "JUSTIFY", NULL);
     return TCL_ERROR;
 }
 
@@ -568,9 +576,7 @@ Tk_GetScreenMM(
 
     d = strtod(string, &end);
     if (end == string) {
-	error:
-	Tcl_AppendResult(interp, "bad screen distance \"", string, "\"", NULL);
-	return TCL_ERROR;
+	goto error;
     }
     while ((*end != '\0') && isspace(UCHAR(*end))) {
 	end++;
@@ -606,6 +612,12 @@ Tk_GetScreenMM(
     }
     *doublePtr = d;
     return TCL_OK;
+
+  error:
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad screen distance \"%s\"", string));
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "SCREEN_DISTANCE", NULL);
+    return TCL_ERROR;
 }
 
 /*
@@ -684,9 +696,7 @@ TkGetDoublePixels(
 
     d = strtod((char *) string, &end);
     if (end == string) {
-    error:
-	Tcl_AppendResult(interp, "bad screen distance \"", string, "\"", NULL);
-	return TCL_ERROR;
+	goto error;
     }
     while ((*end != '\0') && isspace(UCHAR(*end))) {
 	end++;
@@ -725,6 +735,12 @@ TkGetDoublePixels(
     }
     *doublePtr = d;
     return TCL_OK;
+
+  error:
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad screen distance \"%s\"", string));
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "FRACTIONAL_PIXELS", NULL);
+    return TCL_ERROR;
 }
 
 /*
diff --git a/generic/tkGrab.c b/generic/tkGrab.c
index 695690b..2df5552 100644
--- a/generic/tkGrab.c
+++ b/generic/tkGrab.c
@@ -211,10 +211,15 @@ Tk_GrabObjCmd(
 	 * is "grab", but if it has been aliased, the message will be
 	 * incorrect.
 	 */
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "wrong # args: should be \"",
-		Tcl_GetString(objv[0]), " ?-global? window\" or \"",
-		Tcl_GetString(objv[0]), " option ?arg ...?\"", NULL);
+
+	Tcl_WrongNumArgs(interp, 1, objv, "?-global? window");
+	Tcl_AppendResult(interp, " or \"", Tcl_GetString(objv[0]),
+		" option ?arg ...?\"", NULL);
+	/* This API not exposed:
+	 *
+	((Interp *) interp)->flags |= INTERP_ALTERNATE_WRONG_ARGS;
+	Tcl_WrongNumArgs(interp, 1, objv, "option ?arg ...?");
+	 */
 	return TCL_ERROR;
     }
 
@@ -277,17 +282,20 @@ Tk_GrabObjCmd(
 	    }
 	    dispPtr = ((TkWindow *) tkwin)->dispPtr;
 	    if (dispPtr->eventualGrabWinPtr != NULL) {
-		Tcl_SetResult(interp, dispPtr->eventualGrabWinPtr->pathName,
-			TCL_STATIC);
+		Tcl_SetObjResult(interp, TkNewWindowObj((Tk_Window)
+			dispPtr->eventualGrabWinPtr));
 	    }
 	} else {
+	    Tcl_Obj *resultObj = Tcl_NewObj();
+
 	    for (dispPtr = TkGetDisplayList(); dispPtr != NULL;
 		    dispPtr = dispPtr->nextPtr) {
 		if (dispPtr->eventualGrabWinPtr != NULL) {
-		    Tcl_AppendElement(interp,
-			    dispPtr->eventualGrabWinPtr->pathName);
+		    Tcl_ListObjAppendElement(NULL, resultObj, TkNewWindowObj(
+			    (Tk_Window) dispPtr->eventualGrabWinPtr));
 		}
 	    }
+	    Tcl_SetObjResult(interp, resultObj);
 	}
 	return TCL_OK;
 
@@ -340,6 +348,7 @@ Tk_GrabObjCmd(
     case GRABCMD_STATUS: {
 	/* [grab status window] */
 	TkWindow *winPtr;
+	const char *statusString;
 
 	if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 1, objv, "status window");
@@ -352,12 +361,13 @@ Tk_GrabObjCmd(
 	}
 	dispPtr = winPtr->dispPtr;
 	if (dispPtr->eventualGrabWinPtr != winPtr) {
-	    Tcl_SetResult(interp, "none", TCL_STATIC);
+	    statusString = "none";
 	} else if (dispPtr->grabFlags & GRAB_GLOBAL) {
-	    Tcl_SetResult(interp, "global", TCL_STATIC);
+	    statusString = "global";
 	} else {
-	    Tcl_SetResult(interp, "local", TCL_STATIC);
+	    statusString = "local";
 	}
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(statusString, -1));
 	break;
     }
     }
@@ -410,10 +420,7 @@ Tk_Grab(
 	    return TCL_OK;
 	}
 	if (dispPtr->eventualGrabWinPtr->mainPtr != winPtr->mainPtr) {
-	alreadyGrabbed:
-	    Tcl_SetResult(interp, "grab failed: another application has grab",
-		    TCL_STATIC);
-	    return TCL_ERROR;
+	    goto alreadyGrabbed;
 	}
 	Tk_Ungrab((Tk_Window) dispPtr->eventualGrabWinPtr);
     }
@@ -423,7 +430,7 @@ Tk_Grab(
     if (!grabGlobal)
 #else
     if (0)
-#endif
+#endif /* MAC_OSX_TK */
     {
 	Window dummy1, dummy2;
 	int dummy3, dummy4, dummy5, dummy6;
@@ -440,7 +447,7 @@ Tk_Grab(
 	dispPtr->grabFlags &= ~(GRAB_GLOBAL|GRAB_TEMP_GLOBAL);
 	XQueryPointer(dispPtr->display, winPtr->window, &dummy1,
 		&dummy2, &dummy3, &dummy4, &dummy5, &dummy6, &state);
-	if ((state & ALL_BUTTONS) != 0) {
+	if (state & ALL_BUTTONS) {
 	    dispPtr->grabFlags |= GRAB_TEMP_GLOBAL;
 	    goto setGlobalGrab;
 	}
@@ -479,26 +486,7 @@ Tk_Grab(
 	    Tcl_Sleep(100);
 	}
 	if (grabResult != 0) {
-	grabError:
-	    if (grabResult == GrabNotViewable) {
-		Tcl_SetResult(interp, "grab failed: window not viewable",
-			TCL_STATIC);
-	    } else if (grabResult == AlreadyGrabbed) {
-		goto alreadyGrabbed;
-	    } else if (grabResult == GrabFrozen) {
-		Tcl_SetResult(interp,
-			"grab failed: keyboard or pointer frozen", TCL_STATIC);
-	    } else if (grabResult == GrabInvalidTime) {
-		Tcl_SetResult(interp, "grab failed: invalid time",
-			TCL_STATIC);
-	    } else {
-		char msg[64 + TCL_INTEGER_SPACE];
-
-		sprintf(msg, "grab failed for unknown reason (code %d)",
-			grabResult);
-		Tcl_AppendResult(interp, msg, NULL);
-	    }
-	    return TCL_ERROR;
+	    goto grabError;
 	}
 	grabResult = XGrabKeyboard(dispPtr->display, Tk_WindowId(tkwin),
 		False, GrabModeAsync, GrabModeAsync, CurrentTime);
@@ -546,6 +534,31 @@ Tk_Grab(
     }
     QueueGrabWindowChange(dispPtr, winPtr);
     return TCL_OK;
+
+  grabError:
+    if (grabResult == GrabNotViewable) {
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"grab failed: window not viewable", -1));
+	Tcl_SetErrorCode(interp, "TK", "GRAB", "UNVIEWABLE", NULL);
+    } else if (grabResult == AlreadyGrabbed) {
+    alreadyGrabbed:
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"grab failed: another application has grab", -1));
+	Tcl_SetErrorCode(interp, "TK", "GRAB", "GRABBED", NULL);
+    } else if (grabResult == GrabFrozen) {
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"grab failed: keyboard or pointer frozen", -1));
+	Tcl_SetErrorCode(interp, "TK", "GRAB", "FROZEN", NULL);
+    } else if (grabResult == GrabInvalidTime) {
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"grab failed: invalid time", -1));
+	Tcl_SetErrorCode(interp, "TK", "GRAB", "BAD_TIME", NULL);
+    } else {
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"grab failed for unknown reason (code %d)", grabResult));
+	Tcl_SetErrorCode(interp, "TK", "GRAB", "UNKNOWN", NULL);
+    }
+    return TCL_ERROR;
 }
 
 /*
@@ -846,7 +859,7 @@ TkPointerEvent(
 	    }
 	}
 	if (eventPtr->type == ButtonPress) {
-	    if ((eventPtr->xbutton.state & ALL_BUTTONS) == 0) {
+	    if (!(eventPtr->xbutton.state & ALL_BUTTONS)) {
 		if (outsideGrabTree) {
 		    TkChangeEventWindow(eventPtr, dispPtr->grabWinPtr);
 		    Tk_QueueWindowEvent(eventPtr, TCL_QUEUE_HEAD);
diff --git a/generic/tkGrid.c b/generic/tkGrid.c
index 70d463e..19e4442 100644
--- a/generic/tkGrid.c
+++ b/generic/tkGrid.c
@@ -301,7 +301,7 @@ static int		SetSlaveColumn(Tcl_Interp *interp, Gridder *slavePtr,
 			    int column, int numCols);
 static int		SetSlaveRow(Tcl_Interp *interp, Gridder *slavePtr,
 			    int row, int numRows);
-static void		StickyToString(int flags, char *result);
+static Tcl_Obj *	StickyToObj(int flags);
 static int		StringToSticky(const char *string);
 static void		Unlink(Gridder *gridPtr);
 
@@ -402,7 +402,8 @@ Tk_GridObjCmd(
     }
 
     /* This should not happen */
-    Tcl_SetResult(interp, "Internal error in grid.", TCL_STATIC);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj("internal error in grid", -1));
+    Tcl_SetErrorCode(interp, "TK", "API_ABUSE", NULL);
     return TCL_ERROR;
 }
 
@@ -447,8 +448,9 @@ GridAnchorCommand(
 
     if (objc == 3) {
 	gridPtr = masterPtr->masterDataPtr;
-	Tcl_SetResult(interp, (char *) Tk_NameOfAnchor(gridPtr == NULL ?
-		GRID_DEFAULT_ANCHOR : gridPtr->anchor), TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		Tk_NameOfAnchor(gridPtr?gridPtr->anchor:GRID_DEFAULT_ANCHOR),
+		-1));
 	return TCL_OK;
     }
 
@@ -720,7 +722,7 @@ GridInfoCommand(
 {
     register Gridder *slavePtr;
     Tk_Window slave;
-    char buffer[64 + TCL_INTEGER_SPACE * 4];
+    Tcl_Obj *infoObj;
 
     if (objc != 3) {
 	Tcl_WrongNumArgs(interp, 2, objv, "window");
@@ -735,18 +737,24 @@ GridInfoCommand(
 	return TCL_OK;
     }
 
-    Tcl_AppendElement(interp, "-in");
-    Tcl_AppendElement(interp, Tk_PathName(slavePtr->masterPtr->tkwin));
-    sprintf(buffer, " -column %d -row %d -columnspan %d -rowspan %d",
-	    slavePtr->column, slavePtr->row,
-	    slavePtr->numCols, slavePtr->numRows);
-    Tcl_AppendResult(interp, buffer, NULL);
-    TkPrintPadAmount(interp, "ipadx", slavePtr->iPadX/2, slavePtr->iPadX);
-    TkPrintPadAmount(interp, "ipady", slavePtr->iPadY/2, slavePtr->iPadY);
-    TkPrintPadAmount(interp, "padx", slavePtr->padLeft, slavePtr->padX);
-    TkPrintPadAmount(interp, "pady", slavePtr->padTop, slavePtr->padY);
-    StickyToString(slavePtr->sticky, buffer);
-    Tcl_AppendResult(interp, " -sticky ", buffer, NULL);
+    infoObj = Tcl_NewObj();
+    Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-in", -1),
+	    TkNewWindowObj(slavePtr->masterPtr->tkwin));
+    Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-column", -1),
+	    Tcl_NewIntObj(slavePtr->column));
+    Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-row", -1),
+	    Tcl_NewIntObj(slavePtr->row));
+    Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-columnspan", -1),
+	    Tcl_NewIntObj(slavePtr->numCols));
+    Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-rowspan", -1),
+	    Tcl_NewIntObj(slavePtr->numRows));
+    TkAppendPadAmount(infoObj, "-ipadx", slavePtr->iPadX/2, slavePtr->iPadX);
+    TkAppendPadAmount(infoObj, "-ipady", slavePtr->iPadY/2, slavePtr->iPadY);
+    TkAppendPadAmount(infoObj, "-padx", slavePtr->padLeft, slavePtr->padX);
+    TkAppendPadAmount(infoObj, "-pady", slavePtr->padTop, slavePtr->padY);
+    Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-sticky", -1),
+	    StickyToObj(slavePtr->sticky));
+    Tcl_SetObjResult(interp, infoObj);
     return TCL_OK;
 }
 
@@ -994,9 +1002,9 @@ GridRowColumnConfigureCommand(
     string = Tcl_GetString(objv[1]);
     slotType = (*string == 'c') ? COLUMN : ROW;
     if (lObjc == 0) {
-	Tcl_AppendResult(interp, "no ",
-		(slotType == COLUMN) ? "column" : "row",
-		" indices specified", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf("no %s indices specified",
+		(slotType == COLUMN) ? "column" : "row"));
+	Tcl_SetErrorCode(interp, "TK", "GRID", "NO_INDEX", NULL);
 	Tcl_DecrRefCount(listCopy);
 	return TCL_ERROR;
     }
@@ -1007,16 +1015,17 @@ GridRowColumnConfigureCommand(
 
     if ((objc == 4) || (objc == 5)) {
 	if (lObjc != 1) {
-	    Tcl_AppendResult(interp, Tcl_GetString(objv[0]), " ",
-		    Tcl_GetString(objv[1]),
-		    ": must specify a single element on retrieval", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "must specify a single element on retrieval", -1));
+	    Tcl_SetErrorCode(interp, "TK", "GRID", "USAGE", NULL);
 	    Tcl_DecrRefCount(listCopy);
 	    return TCL_ERROR;
 	}
 	if (Tcl_GetIntFromObj(interp, lObjv[0], &slot) != TCL_OK) {
 	    Tcl_AppendResult(interp,
-		    " (when retreiving options only integer indices are "
+		    " (when retrieving options only integer indices are "
 		    "allowed)", NULL);
+	    Tcl_SetErrorCode(interp, "TK", "GRID", "INDEX_FORMAT", NULL);
 	    Tcl_DecrRefCount(listCopy);
 	    return TCL_ERROR;
 	}
@@ -1073,19 +1082,19 @@ GridRowColumnConfigureCommand(
 	    return TCL_ERROR;
 	}
 	if (index == ROWCOL_MINSIZE) {
-	    Tcl_SetObjResult(interp,
-		    Tcl_NewIntObj((ok == TCL_OK) ? slotPtr[slot].minSize : 0));
+	    Tcl_SetObjResult(interp, Tcl_NewIntObj(
+		    (ok == TCL_OK) ? slotPtr[slot].minSize : 0));
 	} else if (index == ROWCOL_WEIGHT) {
-	    Tcl_SetObjResult(interp,
-		    Tcl_NewIntObj((ok == TCL_OK) ? slotPtr[slot].weight : 0));
+	    Tcl_SetObjResult(interp, Tcl_NewIntObj(
+		    (ok == TCL_OK) ? slotPtr[slot].weight : 0));
 	} else if (index == ROWCOL_UNIFORM) {
 	    Tk_Uid value = (ok == TCL_OK) ? slotPtr[slot].uniform : "";
 
-	    Tcl_SetObjResult(interp,
-		    Tcl_NewStringObj(value == NULL ? "" : value, -1));
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    (value == NULL) ? "" : value, -1));
 	} else if (index == ROWCOL_PAD) {
-	    Tcl_SetObjResult(interp,
-		    Tcl_NewIntObj((ok == TCL_OK) ? slotPtr[slot].pad : 0));
+	    Tcl_SetObjResult(interp, Tcl_NewIntObj(
+		    (ok == TCL_OK) ? slotPtr[slot].pad : 0));
 	}
 	Tcl_DecrRefCount(listCopy);
 	return TCL_OK;
@@ -1118,17 +1127,17 @@ GridRowColumnConfigureCommand(
 
 	    slavePtr = GetGrid(slave);
 	    if (slavePtr->masterPtr != masterPtr) {
-		Tcl_AppendResult(interp, Tcl_GetString(objv[0]), " ",
-			Tcl_GetString(objv[1]), ": the window \"",
-			Tcl_GetString(lObjv[j]), "\" is not managed by \"",
-		 	Tcl_GetString(objv[2]), "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"the window \"%s\" is not managed by \"%s\"",
+			Tcl_GetString(lObjv[j]), Tcl_GetString(objv[2])));
+		Tcl_SetErrorCode(interp, "TK", "GRID", "NOT_MASTER", NULL);
 		Tcl_DecrRefCount(listCopy);
 		return TCL_ERROR;
 	    }
 	} else {
-	    Tcl_AppendResult(interp, Tcl_GetString(objv[0]), " ",
-		    Tcl_GetString(objv[1]), ": illegal index \"",
-		    Tcl_GetString(lObjv[j]), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "illegal index \"%s\"", Tcl_GetString(lObjv[j])));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "GRID_INDEX", NULL);
 	    Tcl_DecrRefCount(listCopy);
 	    return TCL_ERROR;
 	}
@@ -1148,10 +1157,11 @@ GridRowColumnConfigureCommand(
 	    for (slot = first; slot <= last; slot++) {
 		ok = CheckSlotData(masterPtr, slot, slotType, /*checkOnly*/ 0);
 		if (ok != TCL_OK) {
-		    Tcl_AppendResult(interp, Tcl_GetString(objv[0]), " ",
-			    Tcl_GetString(objv[1]), ": \"",
-			    Tcl_GetString(lObjv[j]),
-			    "\" is out of range", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "\"%s\" is out of range",
+			    Tcl_GetString(lObjv[j])));
+		    Tcl_SetErrorCode(interp, "TK", "GRID", "INDEX_RANGE",
+			    NULL);
 		    Tcl_DecrRefCount(listCopy);
 		    return TCL_ERROR;
 		}
@@ -1185,11 +1195,8 @@ GridRowColumnConfigureCommand(
 			    Tcl_DecrRefCount(listCopy);
 			    return TCL_ERROR;
 			} else if (wt < 0) {
-			    Tcl_AppendResult(interp, "invalid arg \"",
-				    Tcl_GetString(objv[i]),
-				    "\": should be non-negative", NULL);
 			    Tcl_DecrRefCount(listCopy);
-			    return TCL_ERROR;
+			    goto negativeIndex;
 			} else {
 			    slotPtr[slot].weight = wt;
 			}
@@ -1206,11 +1213,8 @@ GridRowColumnConfigureCommand(
 			    Tcl_DecrRefCount(listCopy);
 			    return TCL_ERROR;
 			} else if (size < 0) {
-			    Tcl_AppendResult(interp, "invalid arg \"",
-				    Tcl_GetString(objv[i]),
-				    "\": should be non-negative", NULL);
 			    Tcl_DecrRefCount(listCopy);
-			    return TCL_ERROR;
+			    goto negativeIndex;
 			} else {
 			    slotPtr[slot].pad = size;
 			}
@@ -1259,6 +1263,13 @@ GridRowColumnConfigureCommand(
 	Tcl_DoWhenIdle(ArrangeGrid, masterPtr);
     }
     return TCL_OK;
+
+  negativeIndex:
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "invalid arg \"%s\": should be non-negative",
+	    Tcl_GetString(objv[i])));
+    Tcl_SetErrorCode(interp, "TK", "GRID", "NEG_INDEX", NULL);
+    return TCL_ERROR;
 }
 
 /*
@@ -1361,8 +1372,9 @@ GridSlavesCommand(
 	    return TCL_ERROR;
 	}
 	if (value < 0) {
-	    Tcl_AppendResult(interp, Tcl_GetString(objv[i]),
-		    " is an invalid value: should NOT be < 0", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "%d is an invalid value: should NOT be < 0", value));
+	    Tcl_SetErrorCode(interp, "TK", "GRID", "NEG_INDEX", NULL);
 	    return TCL_ERROR;
 	}
 	if (index == SLAVES_COLUMN) {
@@ -1380,11 +1392,11 @@ GridSlavesCommand(
     res = Tcl_NewListObj(0, NULL);
     for (slavePtr = masterPtr->slavePtr; slavePtr != NULL;
 	    slavePtr = slavePtr->nextPtr) {
-	if (column>=0 && (slavePtr->column > column
+	if ((column >= 0) && (slavePtr->column > column
 		|| slavePtr->column+slavePtr->numCols-1 < column)) {
 	    continue;
 	}
-	if (row>=0 && (slavePtr->row > row ||
+	if ((row >= 0) && (slavePtr->row > row ||
 		slavePtr->row+slavePtr->numRows-1 < row)) {
 	    continue;
 	}
@@ -2528,7 +2540,8 @@ SetSlaveColumn(
 
     lastCol = ((newColumn >= 0) ? newColumn : 0) + newNumCols;
     if (lastCol >= MAX_ELEMENT) {
-	Tcl_SetResult(interp, "Column out of bounds", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj("column out of bounds",-1));
+	Tcl_SetErrorCode(interp, "TK", "GRID", "BAD_COLUMN", NULL);
 	return TCL_ERROR;
     }
 
@@ -2568,7 +2581,8 @@ SetSlaveRow(
 
     lastRow = ((newRow >= 0) ? newRow : 0) + newNumRows;
     if (lastRow >= MAX_ELEMENT) {
-	Tcl_SetResult(interp, "Row out of bounds", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj("row out of bounds", -1));
+	Tcl_SetErrorCode(interp, "TK", "GRID", "BAD_ROW", NULL);
 	return TCL_ERROR;
     }
 
@@ -2992,24 +3006,27 @@ ConfigureSlaves(
 	    continue;
     	}
 	if (length > 1 && i == 0) {
-	    Tcl_AppendResult(interp, "bad argument \"", string,
-		    "\": must be name of window", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad argument \"%s\": must be name of window", string));
+	    Tcl_SetErrorCode(interp, "TK", "GRID", "BAD_PARAMETER", NULL);
 	    return TCL_ERROR;
 	}
     	if (length > 1 && firstChar == '-') {
 	    break;
 	}
 	if (length > 1) {
-	    Tcl_AppendResult(interp, "unexpected parameter, \"",
-		    string, "\", in configure list. ",
-		    "Should be window name or option", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "unexpected parameter \"%s\" in configure list:"
+		    " should be window name or option", string));
+	    Tcl_SetErrorCode(interp, "TK", "GRID", "BAD_PARAMETER", NULL);
 	    return TCL_ERROR;
 	}
 
 	if ((firstChar == REL_HORIZ) && ((numWindows == 0) ||
 		(prevChar == REL_SKIP) || (prevChar == REL_VERT))) {
-	    Tcl_AppendResult(interp,
-		    "Must specify window before shortcut '-'.", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "must specify window before shortcut '-'", -1));
+	    Tcl_SetErrorCode(interp, "TK", "GRID", "SHORTCUT_USAGE", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -3018,14 +3035,18 @@ ConfigureSlaves(
 	    continue;
 	}
 
-	Tcl_AppendResult(interp, "invalid window shortcut, \"",
-		string, "\" should be '-', 'x', or '^'", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"invalid window shortcut, \"%s\" should be '-', 'x', or '^'",
+		string));
+	Tcl_SetErrorCode(interp, "TK", "GRID", "SHORTCUT_USAGE", NULL);
 	return TCL_ERROR;
     }
     numWindows = i;
 
     if ((objc - numWindows) & 1) {
-	Tcl_AppendResult(interp, "extra option or option with no value", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"extra option or option with no value", -1));
+	Tcl_SetErrorCode(interp, "TK", "GRID", "BAD_PARAMETER", NULL);
 	return TCL_ERROR;
     }
 
@@ -3051,10 +3072,10 @@ ConfigureSlaves(
 	} else if (index == CONF_ROW) {
 	    if (Tcl_GetIntFromObj(interp, objv[i+1], &tmp) != TCL_OK
 		    || tmp < 0) {
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "bad row value \"",
-			Tcl_GetString(objv[i+1]), "\": must be ",
-			"a non-negative integer", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"bad row value \"%s\": must be a non-negative integer",
+			Tcl_GetString(objv[i+1])));
+		Tcl_SetErrorCode(interp, "TK", "VALUE", "POSITIVE_INT", NULL);
 		return TCL_ERROR;
 	    }
 	    defaultRow = tmp;
@@ -3116,8 +3137,10 @@ ConfigureSlaves(
 	}
 
 	if (Tk_TopWinHierarchy(slave)) {
-	    Tcl_AppendResult(interp, "can't manage \"", Tcl_GetString(objv[j]),
-		    "\": it's a top-level window", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't manage \"%s\": it's a top-level window",
+		    Tcl_GetString(objv[j])));
+	    Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "TOPLEVEL", NULL);
 	    return TCL_ERROR;
 	}
 	slavePtr = GetGrid(slave);
@@ -3144,9 +3167,10 @@ ConfigureSlaves(
 	    case CONF_COLUMN:
 		if (Tcl_GetIntFromObj(NULL, objv[i+1], &tmp) != TCL_OK
 			|| tmp < 0) {
-		    Tcl_AppendResult(interp, "bad column value \"",
-			    Tcl_GetString(objv[i+1]), "\": must be ",
-			    "a non-negative integer", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad column value \"%s\": must be a non-negative integer",
+			    Tcl_GetString(objv[i+1])));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "COLUMN", NULL);
 		    return TCL_ERROR;
 		}
 		if (SetSlaveColumn(interp, slavePtr, tmp, -1) != TCL_OK) {
@@ -3156,9 +3180,10 @@ ConfigureSlaves(
 	    case CONF_COLUMNSPAN:
 		if (Tcl_GetIntFromObj(NULL, objv[i+1], &tmp) != TCL_OK
 			|| tmp <= 0) {
-		    Tcl_AppendResult(interp, "bad columnspan value \"",
-			    Tcl_GetString(objv[i+1]), "\": must be ",
-			    "a positive integer", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad columnspan value \"%s\": must be a positive integer",
+			    Tcl_GetString(objv[i+1])));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "SPAN", NULL);
 		    return TCL_ERROR;
 		}
 		if (SetSlaveColumn(interp, slavePtr, -1, tmp) != TCL_OK) {
@@ -3171,8 +3196,9 @@ ConfigureSlaves(
 		    return TCL_ERROR;
 		}
 		if (other == slave) {
-		    Tcl_SetResult(interp, "Window can't be managed in itself",
-			    TCL_STATIC);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "window can't be managed in itself", -1));
+		    Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "SELF", NULL);
 		    return TCL_ERROR;
 		}
 		positionGiven = 1;
@@ -3183,9 +3209,11 @@ ConfigureSlaves(
 		int sticky = StringToSticky(Tcl_GetString(objv[i+1]));
 
 		if (sticky == -1) {
-		    Tcl_AppendResult(interp, "bad stickyness value \"",
-			    Tcl_GetString(objv[i+1]), "\": must be ",
-			    "a string containing n, e, s, and/or w", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad stickyness value \"%s\": must be"
+			    " a string containing n, e, s, and/or w",
+			    Tcl_GetString(objv[i+1])));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "STICKY", NULL);
 		    return TCL_ERROR;
 		}
 		slavePtr->sticky = sticky;
@@ -3194,9 +3222,10 @@ ConfigureSlaves(
 	    case CONF_IPADX:
 		if ((Tk_GetPixelsFromObj(NULL, slave, objv[i+1],
 			&tmp) != TCL_OK) || (tmp < 0)) {
-		    Tcl_AppendResult(interp, "bad ipadx value \"",
-			    Tcl_GetString(objv[i+1]), "\": must be ",
-			    "positive screen distance", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad ipadx value \"%s\": must be positive screen distance",
+			    Tcl_GetString(objv[i+1])));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "INT_PAD", NULL);
 		    return TCL_ERROR;
 		}
 		slavePtr->iPadX = tmp * 2;
@@ -3204,9 +3233,10 @@ ConfigureSlaves(
 	    case CONF_IPADY:
 		if ((Tk_GetPixelsFromObj(NULL, slave, objv[i+1],
 			&tmp) != TCL_OK) || (tmp < 0)) {
-		    Tcl_AppendResult(interp, "bad ipady value \"",
-			    Tcl_GetString(objv[i+1]), "\": must be ",
-			    "positive screen distance", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad ipady value \"%s\": must be positive screen distance",
+			    Tcl_GetString(objv[i+1])));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "INT_PAD", NULL);
 		    return TCL_ERROR;
 		}
 		slavePtr->iPadY = tmp * 2;
@@ -3226,9 +3256,10 @@ ConfigureSlaves(
 	    case CONF_ROW:
 		if (Tcl_GetIntFromObj(NULL, objv[i+1], &tmp) != TCL_OK
 			|| tmp < 0) {
-		    Tcl_AppendResult(interp, "bad row value \"",
-			    Tcl_GetString(objv[i+1]),
-			    "\": must be a non-negative integer", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad row value \"%s\": must be a non-negative integer",
+			    Tcl_GetString(objv[i+1])));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "COLUMN", NULL);
 		    return TCL_ERROR;
 		}
 		if (SetSlaveRow(interp, slavePtr, tmp, -1) != TCL_OK) {
@@ -3238,9 +3269,10 @@ ConfigureSlaves(
 	    case CONF_ROWSPAN:
 		if ((Tcl_GetIntFromObj(NULL, objv[i+1], &tmp) != TCL_OK)
 			|| tmp <= 0) {
-		    Tcl_AppendResult(interp, "bad rowspan value \"",
-			    Tcl_GetString(objv[i+1]),
-			    "\": must be a positive integer", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad rowspan value \"%s\": must be a positive integer",
+			    Tcl_GetString(objv[i+1])));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "SPAN", NULL);
 		    return TCL_ERROR;
 		}
 		if (SetSlaveRow(interp, slavePtr, -1, tmp) != TCL_OK) {
@@ -3305,8 +3337,10 @@ ConfigureSlaves(
 		break;
 	    }
 	    if (Tk_TopWinHierarchy(ancestor)) {
-		Tcl_AppendResult(interp, "can't put ", Tcl_GetString(objv[j]),
-			" inside ", Tk_PathName(masterPtr->tkwin), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"can't put %s inside %s", Tcl_GetString(objv[j]),
+			Tk_PathName(masterPtr->tkwin)));
+		Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "HIERARCHY", NULL);
 		Unlink(slavePtr);
 		return TCL_ERROR;
 	    }
@@ -3317,9 +3351,10 @@ ConfigureSlaves(
 	 */
 
      	if (masterPtr->masterPtr == slavePtr) {
-	    Tcl_AppendResult(interp, "can't put ", Tcl_GetString(objv[j]),
-		    " inside ", Tk_PathName(masterPtr->tkwin),
-		    ", would cause management loop.", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't put %s inside %s, would cause management loop",
+		    Tcl_GetString(objv[j]), Tk_PathName(masterPtr->tkwin)));
+	    Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "LOOP", NULL);
 	    Unlink(slavePtr);
 	    return TCL_ERROR;
      	}
@@ -3379,8 +3414,8 @@ ConfigureSlaves(
     numSkip = 0;
     for (j = 0; j < numWindows; j++) {
 	struct Gridder *otherPtr;
-	int match;		 /* Found a match for the ^ */
-	int lastRow, lastColumn; /* Implied end of table. */
+	int match;			/* Found a match for the ^ */
+	int lastRow, lastColumn;	/* Implied end of table. */
 
 	string = Tcl_GetString(objv[j]);
     	firstChar = string[0];
@@ -3397,7 +3432,9 @@ ConfigureSlaves(
 	}
 
 	if (masterPtr == NULL) {
-	    Tcl_AppendResult(interp, "can't use '^', cant find master", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't use '^', cant find master", -1));
+	    Tcl_SetErrorCode(interp, "TK", "GRID", "SHORTCUT_USAGE", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -3449,14 +3486,17 @@ ConfigureSlaves(
 	    }
 	}
 	if (!match) {
-	    Tcl_AppendResult(interp, "can't find slave to extend with \"^\".",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't find slave to extend with \"^\"", -1));
+	    Tcl_SetErrorCode(interp, "TK", "GRID", "SHORTCUT_USAGE", NULL);
 	    return TCL_ERROR;
 	}
     }
 
     if (masterPtr == NULL) {
-	Tcl_AppendResult(interp, "can't determine master window", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"can't determine master window", -1));
+	Tcl_SetErrorCode(interp, "TK", "GRID", "SHORTCUT_USAGE", NULL);
 	return TCL_ERROR;
     }
     SetGridSize(masterPtr);
@@ -3477,13 +3517,13 @@ ConfigureSlaves(
 /*
  *----------------------------------------------------------------------
  *
- * StickyToString
+ * StickyToObj
  *
  *	Converts the internal boolean combination of "sticky" bits onto a Tcl
  *	list element containing zero or more of n, s, e, or w.
  *
  * Results:
- *	A string is placed into the "result" pointer.
+ *	A new object is returned that holds the sticky representation.
  *
  * Side effects:
  *	none.
@@ -3491,29 +3531,26 @@ ConfigureSlaves(
  *----------------------------------------------------------------------
  */
 
-static void
-StickyToString(
-    int flags,			/* The sticky flags. */
-    char *result)		/* Where to put the result. */
+static Tcl_Obj *
+StickyToObj(
+    int flags)			/* The sticky flags. */
 {
     int count = 0;
-    if (flags&STICK_NORTH) {
-    	result[count++] = 'n';
-    }
-    if (flags&STICK_EAST) {
-    	result[count++] = 'e';
+    char buffer[4];
+
+    if (flags & STICK_NORTH) {
+    	buffer[count++] = 'n';
     }
-    if (flags&STICK_SOUTH) {
-    	result[count++] = 's';
+    if (flags & STICK_EAST) {
+    	buffer[count++] = 'e';
     }
-    if (flags&STICK_WEST) {
-    	result[count++] = 'w';
+    if (flags & STICK_SOUTH) {
+    	buffer[count++] = 's';
     }
-    if (count) {
-	result[count] = '\0';
-    } else {
-	sprintf(result, "{}");
+    if (flags & STICK_WEST) {
+    	buffer[count++] = 'w';
     }
+    return Tcl_NewStringObj(buffer, count);
 }
 
 /*
diff --git a/generic/tkImage.c b/generic/tkImage.c
index 5fa3671..ffa6f22 100644
--- a/generic/tkImage.c
+++ b/generic/tkImage.c
@@ -225,6 +225,7 @@ Tk_ImageObjCmd(
     char idString[16 + TCL_INTEGER_SPACE];
     TkDisplay *dispPtr = winPtr->dispPtr;
     const char *arg, *name;
+    Tcl_Obj *resultObj;
     ThreadSpecificData *tsdPtr =
             Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
 
@@ -271,8 +272,9 @@ Tk_ImageObjCmd(
 	    }
 	}
 	if (typePtr == NULL) {
-	    Tcl_AppendResult(interp, "image type \"", arg, "\" doesn't exist",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "image type \"%s\" doesn't exist", arg));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "IMAGE_TYPE", arg, NULL);
 	    return TCL_ERROR;
 	}
 
@@ -304,8 +306,10 @@ Tk_ImageObjCmd(
 
 	    topWin = (TkWindow *) TkToplevelWindowForCommand(interp, name);
 	    if (topWin != NULL && winPtr->mainPtr->winPtr == topWin) {
-		Tcl_AppendResult(interp, "images may not be named the ",
-			"same as the main window", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"images may not be named the same as the main window",
+			-1));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "SMASH_MAIN", NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -387,9 +391,8 @@ Tk_ImageObjCmd(
 	    imagePtr->instanceData = typePtr->getProc(imagePtr->tkwin,
 		    masterPtr->masterData);
 	}
-	Tcl_SetResult(interp,
-		Tcl_GetHashKey(&winPtr->mainPtr->imageTable, hPtr),
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		Tcl_GetHashKey(&winPtr->mainPtr->imageTable, hPtr), -1));
 	break;
     }
     case IMAGE_DELETE:
@@ -412,28 +415,34 @@ Tk_ImageObjCmd(
 	    return TCL_ERROR;
 	}
 	hPtr = Tcl_FirstHashEntry(&winPtr->mainPtr->imageTable, &search);
+	resultObj = Tcl_NewObj();
 	for ( ; hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
 	    masterPtr = Tcl_GetHashValue(hPtr);
 	    if (masterPtr->deleted) {
 		continue;
 	    }
-	    Tcl_AppendElement(interp, Tcl_GetHashKey(
-		    &winPtr->mainPtr->imageTable, hPtr));
+	    Tcl_ListObjAppendElement(NULL, resultObj, Tcl_NewStringObj(
+		    Tcl_GetHashKey(&winPtr->mainPtr->imageTable, hPtr), -1));
 	}
+	Tcl_SetObjResult(interp, resultObj);
 	break;
     case IMAGE_TYPES:
 	if (objc != 2) {
 	    Tcl_WrongNumArgs(interp, 2, objv, NULL);
 	    return TCL_ERROR;
 	}
+	resultObj = Tcl_NewObj();
 	for (typePtr = tsdPtr->imageTypeList; typePtr != NULL;
 		typePtr = typePtr->nextPtr) {
-	    Tcl_AppendElement(interp, typePtr->name);
+	    Tcl_ListObjAppendElement(NULL, resultObj, Tcl_NewStringObj(
+		    typePtr->name, -1));
 	}
 	for (typePtr = tsdPtr->oldImageTypeList; typePtr != NULL;
 		typePtr = typePtr->nextPtr) {
-	    Tcl_AppendElement(interp, typePtr->name);
+	    Tcl_ListObjAppendElement(NULL, resultObj, Tcl_NewStringObj(
+		    typePtr->name, -1));
 	}
+	Tcl_SetObjResult(interp, resultObj);
 	break;
 
     case IMAGE_HEIGHT:
@@ -490,7 +499,8 @@ Tk_ImageObjCmd(
     return TCL_OK;
 
   alreadyDeleted:
-    Tcl_AppendResult(interp, "image \"", arg, "\" doesn't exist", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf("image \"%s\" doesn't exist",arg));
+    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "IMAGE", arg, NULL);
     return TCL_ERROR;
 }
 
@@ -630,7 +640,9 @@ Tk_GetImage(
 
   noSuchImage:
     if (interp) {
-	Tcl_AppendResult(interp, "image \"", name, "\" doesn't exist", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"image \"%s\" doesn't exist", name));
+	Tcl_SetErrorCode(interp, "TK", "LOOKUP", "IMAGE", name, NULL);
     }
     return NULL;
 }
diff --git a/generic/tkImgBmap.c b/generic/tkImgBmap.c
index 82374cb..cdd57dd 100644
--- a/generic/tkImgBmap.c
+++ b/generic/tkImgBmap.c
@@ -152,7 +152,7 @@ static void		ImgBmapConfigureInstance(BitmapInstance *instancePtr);
 static int		ImgBmapConfigureMaster(BitmapMaster *masterPtr,
 			    int argc, Tcl_Obj *const objv[], int flags);
 static int		NextBitmapWord(ParseInfo *parseInfoPtr);
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -207,7 +207,7 @@ ImgBmapCreate(
     *clientDataPtr = masterPtr;
     return TCL_OK;
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -242,7 +242,7 @@ ImgBmapConfigureMaster(
     const char **argv = ckalloc((objc+1) * sizeof(char *));
 
     for (dummy1 = 0; dummy1 < objc; dummy1++) {
-	argv[dummy1]=Tcl_GetString(objv[dummy1]);
+	argv[dummy1] = Tcl_GetString(objv[dummy1]);
     }
     argv[objc] = NULL;
 
@@ -277,8 +277,10 @@ ImgBmapConfigureMaster(
     if ((masterPtr->maskFileString != NULL)
 	    || (masterPtr->maskDataString != NULL)) {
 	if (masterPtr->data == NULL) {
-	    Tcl_SetResult(masterPtr->interp, "can't have mask without bitmap",
-		    TCL_STATIC);
+	    Tcl_SetObjResult(masterPtr->interp, Tcl_NewStringObj(
+		    "can't have mask without bitmap", -1));
+	    Tcl_SetErrorCode(masterPtr->interp, "TK", "IMAGE", "BITMAP",
+		    "NO_BITMAP", NULL);
 	    return TCL_ERROR;
 	}
 	masterPtr->maskData = TkGetBitmapData(masterPtr->interp,
@@ -291,8 +293,10 @@ ImgBmapConfigureMaster(
 		|| (maskHeight != masterPtr->height)) {
 	    ckfree(masterPtr->maskData);
 	    masterPtr->maskData = NULL;
-	    Tcl_SetResult(masterPtr->interp,
-		    "bitmap and mask have different sizes", TCL_STATIC);
+	    Tcl_SetObjResult(masterPtr->interp, Tcl_NewStringObj(
+		    "bitmap and mask have different sizes", -1));
+	    Tcl_SetErrorCode(masterPtr->interp, "TK", "IMAGE", "BITMAP",
+		    "MASK_SIZE", NULL);
 	    return TCL_ERROR;
 	}
     }
@@ -311,7 +315,7 @@ ImgBmapConfigureMaster(
 	    masterPtr->height, masterPtr->width, masterPtr->height);
     return TCL_OK;
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -446,7 +450,7 @@ ImgBmapConfigureInstance(
 	    masterPtr->tkMaster)));
     Tcl_BackgroundError(masterPtr->interp);
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -473,7 +477,7 @@ char *
 TkGetBitmapData(
     Tcl_Interp *interp,		/* For reporting errors, or NULL. */
     const char *string,		/* String describing bitmap. May be NULL. */
-    const char *fileName,		/* Name of file containing bitmap description.
+    const char *fileName,	/* Name of file containing bitmap description.
 				 * Used only if string is NULL. Must not be
 				 * NULL if string is NULL. */
     int *widthPtr, int *heightPtr,
@@ -490,8 +494,10 @@ TkGetBitmapData(
     pi.string = string;
     if (string == NULL) {
 	if ((interp != NULL) && Tcl_IsSafe(interp)) {
-	    Tcl_AppendResult(interp, "can't get bitmap data from a file in a",
-		    " safe interpreter", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't get bitmap data from a file in a safe interpreter",
+		    -1));
+	    Tcl_SetErrorCode(interp, "TK", "SAFE", "BITMAP_FILE", NULL);
 	    return NULL;
 	}
 	expandedFileName = Tcl_TranslateFileName(interp, fileName, &buffer);
@@ -503,8 +509,9 @@ TkGetBitmapData(
 	if (pi.chan == NULL) {
 	    if (interp != NULL) {
 		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "couldn't read bitmap file \"",
-			fileName, "\": ", Tcl_PosixError(interp), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"couldn't read bitmap file \"%s\": %s",
+			fileName, Tcl_PosixError(interp)));
 	    }
 	    return NULL;
 	}
@@ -593,8 +600,11 @@ TkGetBitmapData(
 	    }
 	} else if ((pi.word[0] == '{') && (pi.word[1] == 0)) {
 	    if (interp != NULL) {
-		Tcl_AppendResult(interp, "format error in bitmap data; ",
-			"looks like it's an obsolete X10 bitmap file", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"format error in bitmap data; looks like it's an"
+			" obsolete X10 bitmap file", -1));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "BITMAP", "OBSOLETE",
+			NULL);
 	    }
 	    goto errorCleanup;
 	}
@@ -636,7 +646,9 @@ TkGetBitmapData(
 
   error:
     if (interp != NULL) {
-	Tcl_SetResult(interp, "format error in bitmap data", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"format error in bitmap data", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "BITMAP", "FORMAT", NULL);
     }
 
   errorCleanup:
@@ -648,7 +660,7 @@ TkGetBitmapData(
     }
     return NULL;
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -718,7 +730,7 @@ NextBitmapWord(
     parseInfoPtr->word[parseInfoPtr->wordLength] = 0;
     return TCL_OK;
 }
-
+
 /*
  *--------------------------------------------------------------
  *
@@ -781,7 +793,7 @@ ImgBmapCmd(
 	return TCL_OK;
     }
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -852,7 +864,7 @@ ImgBmapGet(
 
     return instancePtr;
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -912,7 +924,7 @@ ImgBmapDisplay(
 	XSetClipOrigin(display, instancePtr->gc, 0, 0);
     }
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -975,7 +987,7 @@ ImgBmapFree(
     }
     ckfree(instancePtr);
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -1016,7 +1028,7 @@ ImgBmapDelete(
     Tk_FreeOptions(configSpecs, (char *) masterPtr, NULL, 0);
     ckfree(masterPtr);
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -1046,7 +1058,7 @@ ImgBmapCmdDeletedProc(
 	Tk_DeleteImage(masterPtr->interp, Tk_NameOfImage(masterPtr->tkMaster));
     }
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -1077,8 +1089,7 @@ GetByte(
 	return buffer;
     }
 }
-
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -1100,28 +1111,22 @@ GetByte(
  *	   3.  The postscript coordinate system has been scaled so that the
  *	       entire bitmap is one unit squared.
  *
- *	Some postscript implementations cannot handle bitmap strings longer
- *	than about 60k characters. If the bitmap data is that big or bigger,
- *	then we render it by splitting it into several smaller bitmaps.
- *
  * Results:
- *	Returns TCL_OK on success. Returns TCL_ERROR and leaves and error
- *	message in interp->result if there is a problem.
+ *	None.
  *
  * Side effects:
- *	Postscript code is appended to interp->result.
+ *	Postscript code is appended to psObj.
  *
  *----------------------------------------------------------------------
  */
 
-static int
+static void
 ImgBmapPsImagemask(
-    Tcl_Interp *interp,		/* Append postscript to this interpreter */
+    Tcl_Obj *psObj,		/* Append postscript to this buffer. */
     int width, int height,	/* Width and height of the bitmap in pixels */
-    char *data)			/* Data for the bitmap */
+    char *data)			/* Data for the bitmap. */
 {
     int i, j, nBytePerRow;
-    char buffer[200];
 
     /*
      * The bit order of bitmaps in Tk is the opposite of the bit order that
@@ -1150,31 +1155,22 @@ ImgBmapPsImagemask(
       15, 143, 79, 207, 47, 175, 111, 239, 31, 159, 95, 223, 63, 191, 127, 255,
     };
 
-    if (width*height > 60000) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "unable to generate postscript for bitmaps "
-		"larger than 60000 pixels", NULL);
-	return TCL_ERROR;
-    }
-
-    sprintf(buffer, "0 0 moveto %d %d true [%d 0 0 %d 0 %d] {<\n",
+    Tcl_AppendPrintfToObj(psObj,
+	    "0 0 moveto %d %d true [%d 0 0 %d 0 %d] {<\n",
 	    width, height, width, -height, height);
-    Tcl_AppendResult(interp, buffer, NULL);
 
-    nBytePerRow = (width+7)/8;
-    for(i=0; i<height; i++){
-	for(j=0; j<nBytePerRow; j++){
-	    sprintf(buffer, " %02x",
+    nBytePerRow = (width + 7) / 8;
+    for (i=0; i<height; i++) {
+	for (j=0; j<nBytePerRow; j++) {
+	    Tcl_AppendPrintfToObj(psObj, " %02x",
 		    bit_reverse[0xff & data[i*nBytePerRow + j]]);
-	    Tcl_AppendResult(interp, buffer, NULL);
 	}
-	Tcl_AppendResult(interp, "\n", NULL);
+	Tcl_AppendToObj(psObj, "\n", -1);
     }
 
-    Tcl_AppendResult(interp, ">} imagemask \n", NULL);
-    return TCL_OK;
+    Tcl_AppendToObj(psObj, ">} imagemask \n", -1);
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
@@ -1183,7 +1179,6 @@ ImgBmapPsImagemask(
  *	This procedure generates postscript for rendering a bitmap image.
  *
  * Results:
-
  *	On success, this routine writes postscript code into interp->result
  *	and returns TCL_OK TCL_ERROR is returned and an error message is left
  *	in interp->result if anything goes wrong.
@@ -1204,7 +1199,8 @@ ImgBmapPostscript(
     int prepass)
 {
     BitmapMaster *masterPtr = clientData;
-    char buffer[200];
+    Tcl_InterpState interpState;
+    Tcl_Obj *psObj;
 
     if (prepass) {
 	return TCL_OK;
@@ -1214,11 +1210,32 @@ ImgBmapPostscript(
      * There is nothing to do for bitmaps with zero width or height.
      */
 
-    if (width<=0 || height<=0 || masterPtr->width<=0 || masterPtr->height<= 0){
+    if (width<=0 || height<=0 || masterPtr->width<=0 || masterPtr->height<=0){
 	return TCL_OK;
     }
 
     /*
+     * Some postscript implementations cannot handle bitmap strings longer
+     * than about 60k characters. If the bitmap data is that big or bigger,
+     * we bail out.
+     */
+
+    if (masterPtr->width*masterPtr->height > 60000) {
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"unable to generate postscript for bitmaps larger than 60000"
+		" pixels", -1));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "MEMLIMIT", NULL);
+	return TCL_ERROR;
+    }
+
+    /*
+     * Make our working space.
+     */
+
+    psObj = Tcl_NewObj();
+    interpState = Tcl_SaveInterpState(interp, TCL_OK);
+
+    /*
      * Translate the origin of the coordinate system to be the lower-left
      * corner of the bitmap and adjust the scale of the coordinate system so
      * that entire bitmap covers one square unit of the page. The calling
@@ -1227,13 +1244,11 @@ ImgBmapPostscript(
      * necessary here.
      */
 
-    if (x!=0 || y!=0) {
-	sprintf(buffer, "%d %d moveto\n", x, y);
-	Tcl_AppendResult(interp, buffer, NULL);
+    if (x != 0 || y != 0) {
+	Tcl_AppendPrintfToObj(psObj, "%d %d moveto\n", x, y);
     }
-    if (width!=1 || height!=1) {
-	sprintf(buffer, "%d %d scale\n", width, height);
- 	Tcl_AppendResult(interp, buffer, NULL);
+    if (width != 1 || height != 1) {
+	Tcl_AppendPrintfToObj(psObj, "%d %d scale\n", width, height);
     }
 
     /*
@@ -1249,16 +1264,19 @@ ImgBmapPostscript(
 
 	TkParseColor(Tk_Display(tkwin), Tk_Colormap(tkwin), masterPtr->bgUid,
 		&color);
+	Tcl_ResetResult(interp);
 	if (Tk_PostscriptColor(interp, psinfo, &color) != TCL_OK) {
-	    return TCL_ERROR;
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	if (masterPtr->maskData == NULL) {
-	    Tcl_AppendResult(interp,
-		    "0 0 moveto 1 0 rlineto 0 1 rlineto -1 0 rlineto ",
-		    "closepath fill\n", NULL);
-	} else if (ImgBmapPsImagemask(interp, masterPtr->width,
-		masterPtr->height, masterPtr->maskData) != TCL_OK) {
-	    return TCL_ERROR;
+	    Tcl_AppendToObj(psObj,
+		    "0 0 moveto 1 0 rlineto 0 1 rlineto -1 0 rlineto "
+		    "closepath fill\n", -1);
+	} else {
+	    ImgBmapPsImagemask(psObj, masterPtr->width, masterPtr->height,
+		    masterPtr->maskData);
 	}
     }
 
@@ -1271,17 +1289,31 @@ ImgBmapPostscript(
 
 	TkParseColor(Tk_Display(tkwin), Tk_Colormap(tkwin), masterPtr->fgUid,
 		&color);
+	Tcl_ResetResult(interp);
 	if (Tk_PostscriptColor(interp, psinfo, &color) != TCL_OK) {
-	    return TCL_ERROR;
-	}
-	if (ImgBmapPsImagemask(interp, masterPtr->width, masterPtr->height,
-		masterPtr->data) != TCL_OK) {
-	    return TCL_ERROR;
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
+	ImgBmapPsImagemask(psObj, masterPtr->width, masterPtr->height,
+		masterPtr->data);
     }
+
+    /*
+     * Plug the accumulated postscript back into the result.
+     */
+
+    (void) Tcl_RestoreInterpState(interp, interpState);
+    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    Tcl_DecrRefCount(psObj);
     return TCL_OK;
-}
 
+  error:
+    Tcl_DiscardInterpState(interpState);
+    Tcl_DecrRefCount(psObj);
+    return TCL_ERROR;
+}
+
 /*
  * Local Variables:
  * mode: c
diff --git a/generic/tkImgGIF.c b/generic/tkImgGIF.c
index 4cbf94d..fed4da4 100644
--- a/generic/tkImgGIF.c
+++ b/generic/tkImgGIF.c
@@ -430,8 +430,10 @@ FileReadGIF(
 	    return TCL_ERROR;
 	}
 	if (i == (argc-1)) {
-	    Tcl_AppendResult(interp, "no value given for \"",
-		    Tcl_GetString(objv[i]), "\" option", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "no value given for \"%s\" option",
+		    Tcl_GetString(objv[i])));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "OPT_VALUE", NULL);
 	    return TCL_ERROR;
 	}
 	if (Tcl_GetIntFromObj(interp, objv[++i], &index) != TCL_OK) {
@@ -444,13 +446,15 @@ FileReadGIF(
      */
 
     if (!ReadGIFHeader(gifConfPtr, chan, &fileWidth, &fileHeight)) {
-	Tcl_AppendResult(interp, "couldn't read GIF header from file \"",
-		fileName, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"couldn't read GIF header from file \"%s\"", fileName));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "HEADER", NULL);
 	return TCL_ERROR;
     }
     if ((fileWidth <= 0) || (fileHeight <= 0)) {
-	Tcl_AppendResult(interp, "GIF image file \"", fileName,
-		"\" has dimension(s) <= 0", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"GIF image file \"%s\" has dimension(s) <= 0", fileName));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "BOGUS_SIZE", NULL);
 	return TCL_ERROR;
     }
 
@@ -465,7 +469,9 @@ FileReadGIF(
 
     if (BitSet(buf[0], LOCALCOLORMAP)) {	/* Global Colormap */
 	if (!ReadColorMap(gifConfPtr, chan, bitPixel, colorMap)) {
-	    Tcl_AppendResult(interp, "error reading color map", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "error reading color map", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "COLOR_MAP", NULL);
 	    return TCL_ERROR;
 	}
     }
@@ -501,14 +507,18 @@ FileReadGIF(
 	     * Premature end of image.
 	     */
 
-	    Tcl_AppendResult(interp,
-		    "premature end of image data for this index", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "premature end of image data for this index", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "PREMATURE_END",
+		    NULL);
 	    goto error;
 	}
 
 	switch (buf[0]) {
 	case GIF_TERMINATOR:
-	    Tcl_AppendResult(interp, "no image data for this index", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "no image data for this index", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "NO_DATA", NULL);
 	    goto error;
 
 	case GIF_EXTENSION:
@@ -517,23 +527,29 @@ FileReadGIF(
 	     */
 
 	    if (Fread(gifConfPtr, buf, 1, 1, chan) != 1) {
-		Tcl_SetResult(interp,
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
 			"error reading extension function code in GIF image",
-			TCL_STATIC);
+			-1));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "BAD_EXT",
+			NULL);
 		goto error;
 	    }
 	    if (DoExtension(gifConfPtr, chan, buf[0],
 		    gifConfPtr->workingBuffer, &transparent) < 0) {
-		Tcl_SetResult(interp, "error reading extension in GIF image",
-			TCL_STATIC);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"error reading extension in GIF image", -1));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "BAD_EXT",
+			NULL);
 		goto error;
 	    }
 	    continue;
 	case GIF_START:
 	    if (Fread(gifConfPtr, buf, 1, 9, chan) != 9) {
-		Tcl_SetResult(interp,
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
 			"couldn't read left/top/width/height in GIF image",
-			TCL_STATIC);
+			-1));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "DIMENSIONS",
+			NULL);
 		goto error;
 	    }
 	    break;
@@ -561,7 +577,10 @@ FileReadGIF(
 
 	    if (BitSet(buf[8], LOCALCOLORMAP)) {
 		if (!ReadColorMap(gifConfPtr, chan, bitPixel, colorMap)) {
-		    Tcl_AppendResult(interp, "error reading color map", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "error reading color map", -1));
+		    Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF",
+			    "COLOR_MAP", NULL);
 		    goto error;
 		}
 	    }
@@ -608,7 +627,9 @@ FileReadGIF(
 
     if (BitSet(buf[8], LOCALCOLORMAP)) {
 	if (!ReadColorMap(gifConfPtr, chan, bitPixel, colorMap)) {
-	    Tcl_AppendResult(interp, "error reading color map", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "error reading color map", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "COLOR_MAP", NULL);
 	    goto error;
 	}
     }
@@ -659,7 +680,7 @@ FileReadGIF(
 	block.pixelPtr = ckalloc(nBytes);
 
 	if (ReadImage(gifConfPtr, interp, block.pixelPtr, chan, imageWidth,
-		imageHeight, colorMap, srcX, srcY, BitSet(buf[8],INTERLACE),
+		imageHeight, colorMap, srcX, srcY, BitSet(buf[8], INTERLACE),
 		transparent) != TCL_OK) {
 	    ckfree(block.pixelPtr);
 	    goto error;
@@ -677,7 +698,7 @@ FileReadGIF(
      * which suits as well). We're done.
      */
 
-    Tcl_AppendResult(interp, tkImgFmtGIF.name, NULL);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(tkImgFmtGIF.name, -1));
     result = TCL_OK;
 
   error:
@@ -903,19 +924,19 @@ DoExtension(
     int count;
 
     switch (label) {
-    case 0x01:		/* Plain Text Extension */
+    case 0x01:			/* Plain Text Extension */
 	break;
 
-    case 0xff:		/* Application Extension */
+    case 0xff:			/* Application Extension */
 	break;
 
-    case 0xfe:		/* Comment Extension */
+    case 0xfe:			/* Comment Extension */
 	do {
 	    count = GetDataBlock(gifConfPtr, chan, buf);
 	} while (count > 0);
 	return count;
 
-    case 0xf9:		/* Graphic Control Extension */
+    case 0xf9:			/* Graphic Control Extension */
 	count = GetDataBlock(gifConfPtr, chan, buf);
 	if (count < 0) {
 	    return 1;
@@ -1011,13 +1032,14 @@ ReadImage(
      */
 
     if (Fread(gifConfPtr, &initialCodeSize, 1, 1, chan) <= 0) {
-	Tcl_AppendResult(interp, "error reading GIF image: ",
-		Tcl_PosixError(interp), NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"error reading GIF image: %s", Tcl_PosixError(interp)));
 	return TCL_ERROR;
     }
 
     if (initialCodeSize > MAX_LWZ_BITS) {
-	Tcl_SetResult(interp, "malformed image", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj("malformed image", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "MALFORMED", NULL);
 	return TCL_ERROR;
     }
 
@@ -1416,7 +1438,7 @@ Mgetc(
 	handle->data++;
     } while (c == GIF_SPACE);
 
-    if (c>GIF_SPECIAL) {
+    if (c > GIF_SPECIAL) {
 	handle->state = GIF_DONE;
 	return handle->c;
     }
@@ -1689,7 +1711,8 @@ CommonWriteGIF(
     state.pixelPitch = blockPtr->pitch;
     SaveMap(&state, blockPtr);
     if (state.num >= MAXCOLORMAPSIZE) {
-	Tcl_AppendResult(interp, "too many colors", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj("too many colors", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "GIF", "COLORFUL", NULL);
 	return TCL_ERROR;
     }
     if (state.num<2) {
diff --git a/generic/tkImgPNG.c b/generic/tkImgPNG.c
index 8d6721e..b159c45 100644
--- a/generic/tkImgPNG.c
+++ b/generic/tkImgPNG.c
@@ -334,7 +334,9 @@ InitPNGImage(
 
     if (Tcl_ZlibStreamInit(NULL, dir, TCL_ZLIB_FORMAT_ZLIB,
 	    TCL_ZLIB_COMPRESS_DEFAULT, NULL, &pngPtr->stream) != TCL_OK) {
-	Tcl_SetResult(interp, "zlib initialization failed", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"zlib initialization failed", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "ZLIB_INIT", NULL);
 	if (objPtr) {
 	    Tcl_DecrRefCount(objPtr);
 	}
@@ -515,7 +517,9 @@ ReadBase64(
     }
 
     if (destSz) {
-	Tcl_SetResult(interp, "Unexpected end of image data", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"unexpected end of image data", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "EARLY_END", NULL);
 	return TCL_ERROR;
     }
 
@@ -557,7 +561,9 @@ ReadByteArray(
      */
 
     if (pngPtr->strDataLen < destSz) {
-	Tcl_SetResult(interp, "Unexpected end of image data", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"unexpected end of image data", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "EARLY_END", NULL);
 	return TCL_ERROR;
     }
 
@@ -618,14 +624,10 @@ ReadData(
 	int blockSz = PNG_MIN(destSz, PNG_BLOCK_SZ);
 
 	blockSz = Tcl_Read(pngPtr->channel, (char *)destPtr, blockSz);
-
-	/*
-	 * Check for read failure.
-	 */
-
 	if (blockSz < 0) {
 	    /* TODO: failure info... */
-	    Tcl_SetResult(interp, "Channel read failed", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "channel read failed: %s", Tcl_PosixError(interp)));
 	    return TCL_ERROR;
 	}
 
@@ -647,7 +649,9 @@ ReadData(
 	 */
 
 	if (destSz && Tcl_Eof(pngPtr->channel)) {
-	    Tcl_SetResult(interp, "Unexpected end of file ", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "unexpected end of file", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "EOF", NULL);
 	    return TCL_ERROR;
 	}
     }
@@ -732,7 +736,8 @@ CheckCRC(
      */
 
     if (calculated != chunked) {
-	Tcl_SetResult(interp, "CRC check failed", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj("CRC check failed", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "CRC", NULL);
 	return TCL_ERROR;
     }
 
@@ -882,8 +887,10 @@ ReadChunkHeader(
 	temp = PNG_INT32(pc[0], pc[1], pc[2], pc[3]);
 
 	if (temp > INT_MAX) {
-	    Tcl_SetResult(interp, "Chunk size is out of supported range "
-		    "on this architecture", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "chunk size is out of supported range on this architecture",
+		    -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "OUTSIZE", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -967,9 +974,29 @@ ReadChunkHeader(
 	     */
 
 	    if (!(chunkType & PNG_CF_ANCILLARY)) {
-		Tcl_SetResult(interp,
-			"Encountered an unsupported criticial chunk type",
-			TCL_STATIC);
+		if (chunkType & PNG_INT32(128,128,128,128)) {
+		    /*
+		     * No nice ASCII conversion; shouldn't happen either, but
+		     * we'll be doubly careful.
+		     */
+
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "encountered an unsupported criticial chunk type",
+			    -1));
+		} else {
+		    char typeString[5];
+
+		    typeString[0] = (char) ((chunkType >> 24) & 255);
+		    typeString[1] = (char) ((chunkType >> 16) & 255);
+		    typeString[2] = (char) ((chunkType >> 8) & 255);
+		    typeString[3] = (char) (chunkType & 255);
+		    typeString[4] = '\0';
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "encountered an unsupported criticial chunk type"
+			    " \"%s\"", typeString));
+		}
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG",
+			"UNSUPPORTED_CRITICAL", NULL);
 		return TCL_ERROR;
 	    }
 
@@ -980,7 +1007,10 @@ ReadChunkHeader(
 	    for (i=0 ; i<4 ; i++) {
 		if ((pc[i] < 65) || (pc[i] > 122) ||
 			((pc[i] > 90) && (pc[i] < 97))) {
-		    Tcl_SetResult(interp, "Invalid chunk type", TCL_STATIC);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "invalid chunk type", -1));
+		    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG",
+			    "INVALID_CHUNK", NULL);
 		    return TCL_ERROR;
 		}
 	    }
@@ -1036,7 +1066,6 @@ CheckColor(
     Tcl_Interp *interp,
     PNGImage *pngPtr)
 {
-    int result = TCL_OK;
     int offset;
 
     /*
@@ -1049,14 +1078,14 @@ CheckColor(
 	if ((1 != pngPtr->bitDepth) && (2 != pngPtr->bitDepth) &&
 		(4 != pngPtr->bitDepth) && (8 != pngPtr->bitDepth) &&
 		(16 != pngPtr->bitDepth)) {
-	    result = TCL_ERROR;
+	    goto unsupportedDepth;
 	}
 	break;
 
     case PNG_COLOR_RGB:
 	pngPtr->numChannels = 3;
 	if ((8 != pngPtr->bitDepth) && (16 != pngPtr->bitDepth)) {
-	    result = TCL_ERROR;
+	    goto unsupportedDepth;
 	}
 	break;
 
@@ -1064,32 +1093,32 @@ CheckColor(
 	pngPtr->numChannels = 1;
 	if ((1 != pngPtr->bitDepth) && (2 != pngPtr->bitDepth) &&
 		(4 != pngPtr->bitDepth) && (8 != pngPtr->bitDepth)) {
-	    result = TCL_ERROR;
+	    goto unsupportedDepth;
 	}
 	break;
 
     case PNG_COLOR_GRAYALPHA:
 	pngPtr->numChannels = 2;
 	if ((8 != pngPtr->bitDepth) && (16 != pngPtr->bitDepth)) {
-	    result = TCL_ERROR;
+	    goto unsupportedDepth;
 	}
 	break;
 
     case PNG_COLOR_RGBA:
 	pngPtr->numChannels = 4;
 	if ((8 != pngPtr->bitDepth) && (16 != pngPtr->bitDepth)) {
-	    result = TCL_ERROR;
+	unsupportedDepth:
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "bit depth is not allowed for given color type", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_DEPTH", NULL);
+	    return TCL_ERROR;
 	}
 	break;
 
     default:
-	Tcl_SetResult(interp, "Unknown Color Type field", TCL_STATIC);
-	return TCL_ERROR;
-    }
-
-    if (TCL_ERROR == result) {
-	Tcl_SetResult(interp, "Bit depth is not allowed for given color type",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"unknown color type field %d", pngPtr->colorType));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "UNKNOWN_COLOR", NULL);
 	return TCL_ERROR;
     }
 
@@ -1117,9 +1146,10 @@ CheckColor(
      */
 
     if (pngPtr->block.width > INT_MAX / pngPtr->block.pixelSize) {
-	Tcl_SetResult(interp,
-		"Image pitch is out of supported range on this architecture",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"image pitch is out of supported range on this architecture",
+		-1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "PITCH", NULL);
 	return TCL_ERROR;
     }
 
@@ -1131,8 +1161,10 @@ CheckColor(
      */
 
     if (pngPtr->block.height > INT_MAX / pngPtr->block.pitch) {
-	Tcl_SetResult(interp, "Image total size is out of supported range "
-		"on this architecture", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"image total size is out of supported range on this architecture",
+		-1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "SIZE", NULL);
 	return TCL_ERROR;
     }
 
@@ -1159,8 +1191,9 @@ CheckColor(
 	pngPtr->bytesPerPixel = (pngPtr->bitDepth > 8) ? 8 : 4;
 	break;
     default:
-	Tcl_SetResult(interp, "internal error - unknown color type",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"unknown color type %d", pngPtr->colorType));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "UNKNOWN_COLOR", NULL);
 	return TCL_ERROR;
     }
 
@@ -1240,8 +1273,9 @@ ReadIHDR(
     }
 
     if (mismatch) {
-	Tcl_SetResult(interp, "Data stream does not have a PNG signature",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"data stream does not have a PNG signature", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "NO_SIG", NULL);
 	return TCL_ERROR;
     }
 
@@ -1257,12 +1291,16 @@ ReadIHDR(
      */
 
     if (chunkType != CHUNK_IHDR) {
-	Tcl_SetResult(interp, "Expected IHDR chunk type", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"expected IHDR chunk type", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "NO_IHDR", NULL);
 	return TCL_ERROR;
     }
 
     if (chunkSz != 13) {
-	Tcl_SetResult(interp, "Invalid IHDR chunk size", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"invalid IHDR chunk size", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_IHDR", NULL);
 	return TCL_ERROR;
     }
 
@@ -1281,9 +1319,10 @@ ReadIHDR(
     }
 
     if (!width || !height || (width > INT_MAX) || (height > INT_MAX)) {
-	Tcl_SetResult(interp,
-		"Image dimensions are invalid or beyond architecture limits",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"image dimensions are invalid or beyond architecture limits",
+		-1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "DIMENSIONS", NULL);
 	return TCL_ERROR;
     }
 
@@ -1325,8 +1364,10 @@ ReadIHDR(
 	return TCL_ERROR;
     }
 
-    if (PNG_COMPRESS_DEFLATE != pngPtr->compression) {
-	Tcl_SetResult(interp, "Unknown compression method", TCL_STATIC);
+    if (pngPtr->compression != PNG_COMPRESS_DEFLATE) {
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"unknown compression method %d", pngPtr->compression));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_COMPRESS", NULL);
 	return TCL_ERROR;
     }
 
@@ -1339,8 +1380,10 @@ ReadIHDR(
 	return TCL_ERROR;
     }
 
-    if (PNG_FILTMETH_STANDARD != pngPtr->filter) {
-	Tcl_SetResult(interp, "Unknown filter method", TCL_STATIC);
+    if (pngPtr->filter != PNG_FILTMETH_STANDARD) {
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"unknown filter method %d", pngPtr->filter));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_FILTER", NULL);
 	return TCL_ERROR;
     }
 
@@ -1354,7 +1397,9 @@ ReadIHDR(
 	break;
 
     default:
-	Tcl_SetResult(interp, "Unknown interlace method", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"unknown interlace method %d", pngPtr->interlace));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_INTERLACE", NULL);
 	return TCL_ERROR;
     }
 
@@ -1397,8 +1442,10 @@ ReadPLTE(
     switch (pngPtr->colorType) {
     case PNG_COLOR_GRAY:
     case PNG_COLOR_GRAYALPHA:
-	Tcl_SetResult(interp, "PLTE chunk type forbidden for grayscale",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"PLTE chunk type forbidden for grayscale", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "PLTE_UNEXPECTED",
+		NULL);
 	return TCL_ERROR;
 
     default:
@@ -1412,7 +1459,9 @@ ReadPLTE(
      */
 
     if (!chunkSz || (chunkSz > PNG_PLTE_MAXSZ) || (chunkSz % 3)) {
-	Tcl_SetResult(interp, "Invalid palette chunk size", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"invalid palette chunk size", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_PLTE", NULL);
 	return TCL_ERROR;
     }
 
@@ -1474,9 +1523,10 @@ ReadTRNS(
     int i;
 
     if (pngPtr->colorType & PNG_COLOR_ALPHA) {
-	Tcl_SetResult(interp,
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		"tRNS chunk not allowed color types with a full alpha channel",
-		TCL_STATIC);
+		-1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "INVALID_TRNS", NULL);
 	return TCL_ERROR;
     }
 
@@ -1486,7 +1536,9 @@ ReadTRNS(
      */
 
     if (chunkSz > PNG_TRNS_MAXSZ) {
-	Tcl_SetResult(interp, "Invalid tRNS chunk size", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"invalid tRNS chunk size", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_TRNS", NULL);
 	return TCL_ERROR;
     }
 
@@ -1515,9 +1567,9 @@ ReadTRNS(
 	 */
 
 	if (chunkSz > pngPtr->paletteLen) {
-	    Tcl_SetResult(interp,
-		    "Size of tRNS chunk is too large for the palette",
-		    TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "size of tRNS chunk is too large for the palette", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "TRNS_SIZE", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1533,9 +1585,10 @@ ReadTRNS(
 	 */
 
 	if (chunkSz != 2) {
-	    Tcl_SetResult(interp,
-		    "Invalid tRNS chunk size - must 2 bytes for grayscale",
-		    TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "invalid tRNS chunk size - must 2 bytes for grayscale",
+		    -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_TRNS", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1559,9 +1612,9 @@ ReadTRNS(
 	 */
 
 	if (chunkSz != 6) {
-	    Tcl_SetResult(interp,
-		    "Invalid tRNS chunk size - must 6 bytes for RGB",
-		    TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "invalid tRNS chunk size - must 6 bytes for RGB", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_TRNS", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1742,7 +1795,9 @@ UnfilterLine(
 	}
 	break;
     default:
-	Tcl_SetResult(interp, "Invalid filter type", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"invalid filter type %d", *thisLine));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_FILTER", NULL);
 	return TCL_ERROR;
     }
 
@@ -1909,7 +1964,7 @@ DecodeLine(
 	 */
 
 	if ((PNG_COLOR_PLTE != pngPtr->colorType) &&
-		((pngPtr->colorType & PNG_COLOR_ALPHA) == 0)) {
+		!(pngPtr->colorType & PNG_COLOR_ALPHA)) {
 	    unsigned char alpha;
 
 	    if (pngPtr->useTRNS) {
@@ -2049,8 +2104,10 @@ ReadIDAT(
 	     */
 
 	    if (Tcl_ZlibStreamEof(pngPtr->stream)) {
-		Tcl_SetResult(interp, "Extra data after end of zlib stream",
-			TCL_STATIC);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"extra data after end of zlib stream", -1));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "EXTRA_DATA",
+			NULL);
 		return TCL_ERROR;
 	    }
 
@@ -2089,9 +2146,11 @@ ReadIDAT(
 
 	if (len2 == pngPtr->phaseSize) {
 	    if (pngPtr->phase > 7) {
-		Tcl_SetResult(interp,
-			"Extra data after final scan line of final phase",
-			TCL_STATIC);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"extra data after final scan line of final phase",
+			-1));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "EXTRA_DATA",
+			NULL);
 		return TCL_ERROR;
 	    }
 
@@ -2134,8 +2193,9 @@ ReadIDAT(
      */
 
     if (chunkSz != 0) {
-	Tcl_AppendResult(interp,
-		"compressed data after stream finalize in PNG data", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"compressed data after stream finalize in PNG data", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "EXTRA_DATA", NULL);
 	return TCL_ERROR;
     }
 
@@ -2271,9 +2331,10 @@ ParseFormat(
 	    }
 
 	    if ((pngPtr->alpha < 0.0) || (pngPtr->alpha > 1.0)) {
-		Tcl_SetResult(interp,
-			"-alpha value must be between 0.0 and 1.0",
-			TCL_STATIC);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"-alpha value must be between 0.0 and 1.0", -1));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_ALPHA",
+			NULL);
 		return TCL_ERROR;
 	    }
 	    break;
@@ -2363,8 +2424,9 @@ DecodePNG(
 	    return TCL_ERROR;
 	}
     } else if (PNG_COLOR_PLTE == pngPtr->colorType) {
-	Tcl_SetResult(interp, "PLTE chunk required for indexed color",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"PLTE chunk required for indexed color", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "NEED_PLTE", NULL);
 	return TCL_ERROR;
     }
 
@@ -2399,9 +2461,10 @@ DecodePNG(
      * interested in IDAT. The others should have been skipped.
      */
 
-    if (CHUNK_IDAT != chunkType) {
-	Tcl_SetResult(interp, "At least one IDAT chunk is required",
-		TCL_STATIC);
+    if (chunkType != CHUNK_IDAT) {
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"at least one IDAT chunk is required", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "NEED_IDAT", NULL);
 	return TCL_ERROR;
     }
 
@@ -2422,9 +2485,10 @@ DecodePNG(
      */
 
     if (pngPtr->block.width > ((INT_MAX - 1) / (pngPtr->numChannels * 2))) {
-	Tcl_SetResult(interp,
-		"Line size is out of supported range on this architecture",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"line size is out of supported range on this architecture",
+		-1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "LINE_SIZE", NULL);
 	return TCL_ERROR;
     }
 
@@ -2449,7 +2513,9 @@ DecodePNG(
 
     pngPtr->block.pixelPtr = attemptckalloc(pngPtr->blockLen);
     if (!pngPtr->block.pixelPtr) {
-	Tcl_SetResult(interp, "Memory allocation failed", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"memory allocation failed", -1));
+	Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 	return TCL_ERROR;
     }
 
@@ -2499,7 +2565,9 @@ DecodePNG(
      */
 
     if (!Tcl_ZlibStreamEof(pngPtr->stream)) {
-	Tcl_AppendResult(interp, "unfinalized data stream in PNG data", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"unfinalized data stream in PNG data", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "EXTRA_DATA", NULL);
 	return TCL_ERROR;
     }
 
@@ -2523,8 +2591,9 @@ DecodePNG(
      */
 
     if (chunkSz) {
-	Tcl_SetResult(interp, "IEND chunk contents must be empty",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"IEND chunk contents must be empty", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_IEND", NULL);
 	return TCL_ERROR;
     }
 
@@ -2543,7 +2612,9 @@ DecodePNG(
 
 #if 0
     if (ReadData(interp, pngPtr, &c, 1, NULL) != TCL_ERROR) {
-	Tcl_SetResult(interp, "Extra data following IEND chunk", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"extra data following IEND chunk", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "BAD_IEND", NULL);
 	return TCL_ERROR;
     }
 #endif
@@ -2795,24 +2866,25 @@ WriteData(
 	Tcl_GetByteArrayFromObj(pngPtr->objDataPtr, &objSz);
 
 	if (objSz > INT_MAX - srcSz) {
-	    Tcl_SetResult(interp,
-		    "Image too large to store completely in byte array",
-		    TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "image too large to store completely in byte array", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "TOO_LARGE", NULL);
 	    return TCL_ERROR;
 	}
 
 	destPtr = Tcl_SetByteArrayLength(pngPtr->objDataPtr, objSz + srcSz);
 
 	if (!destPtr) {
-	    Tcl_SetResult(interp, "Memory allocation failed", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "memory allocation failed", -1));
+	    Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 	    return TCL_ERROR;
 	}
 
 	memcpy(destPtr+objSz, srcPtr, srcSz);
     } else if (Tcl_Write(pngPtr->channel, (const char *) srcPtr, srcSz) < 0) {
-	/* TODO: reason */
-
-	Tcl_SetResult(interp, "Write to channel failed", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"write to channel failed: %s", Tcl_PosixError(interp)));
 	return TCL_ERROR;
     }
 
@@ -3127,7 +3199,9 @@ WriteIDAT(
 	}
 	if (Tcl_ZlibStreamPut(pngPtr->stream, pngPtr->thisLineObj,
 		flush) != TCL_OK) {
-	    Tcl_SetResult(interp, "deflate() returned error", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "deflate() returned error", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "DEFLATE", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -3301,8 +3375,9 @@ EncodePNG(
 
     if ((blockPtr->width > (INT_MAX - 1) / (pngPtr->bytesPerPixel)) ||
 	    (blockPtr->height > INT_MAX / pngPtr->lineSize)) {
-	Tcl_SetResult(interp, "Image is too large to encode pixel data",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"image is too large to encode pixel data", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PNG", "TOO_LARGE", NULL);
 	return TCL_ERROR;
     }
 
diff --git a/generic/tkImgPPM.c b/generic/tkImgPPM.c
index 527efa2..edd1b71 100644
--- a/generic/tkImgPPM.c
+++ b/generic/tkImgPPM.c
@@ -147,21 +147,22 @@ FileReadPPM(
 
     type = ReadPPMFileHeader(chan, &fileWidth, &fileHeight, &maxIntensity);
     if (type == 0) {
-	Tcl_AppendResult(interp, "couldn't read raw PPM header from file \"",
-		fileName, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"couldn't read raw PPM header from file \"%s\"", fileName));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "NO_HEADER", NULL);
 	return TCL_ERROR;
     }
     if ((fileWidth <= 0) || (fileHeight <= 0)) {
-	Tcl_AppendResult(interp, "PPM image file \"", fileName,
-		"\" has dimension(s) <= 0", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"PPM image file \"%s\" has dimension(s) <= 0", fileName));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "DIMENSIONS", NULL);
 	return TCL_ERROR;
     }
     if ((maxIntensity <= 0) || (maxIntensity >= 256)) {
-	char buffer[TCL_INTEGER_SPACE];
-
-	sprintf(buffer, "%d", maxIntensity);
-	Tcl_AppendResult(interp, "PPM image file \"", fileName,
-		"\" has bad maximum intensity value ", buffer, NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"PPM image file \"%s\" has bad maximum intensity value %d",
+		fileName, maxIntensity));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "INTENSITY", NULL);
 	return TCL_ERROR;
     }
 
@@ -218,10 +219,12 @@ FileReadPPM(
 	}
 	count = Tcl_Read(chan, (char *) pixelPtr, nBytes);
 	if (count != nBytes) {
-	    Tcl_AppendResult(interp, "error reading PPM image file \"",
-		    fileName, "\": ",
-		    Tcl_Eof(chan) ? "not enough data" : Tcl_PosixError(interp),
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "error reading PPM image file \"%s\": %s", fileName,
+		    Tcl_Eof(chan)?"not enough data":Tcl_PosixError(interp)));
+	    if (Tcl_Eof(chan)) {
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "EOF", NULL);
+	    }
 	    ckfree(pixelPtr);
 	    return TCL_ERROR;
 	}
@@ -325,8 +328,8 @@ FileWritePPM(
     chan = NULL;
 
   writeerror:
-    Tcl_AppendResult(interp, "error writing \"", fileName, "\": ",
-	    Tcl_PosixError(interp), NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf("error writing \"%s\": %s",
+	    fileName, Tcl_PosixError(interp)));
     if (chan != NULL) {
 	Tcl_Close(NULL, chan);
     }
@@ -482,22 +485,22 @@ StringReadPPM(
     type = ReadPPMStringHeader(dataObj, &fileWidth, &fileHeight,
 	    &maxIntensity, &dataBuffer, &dataSize);
     if (type == 0) {
-	Tcl_AppendResult(interp, "couldn't read raw PPM header from string",
-		NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"couldn't read raw PPM header from string", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "NO_HEADER", NULL);
 	return TCL_ERROR;
     }
     if ((fileWidth <= 0) || (fileHeight <= 0)) {
-	Tcl_AppendResult(interp, "PPM image data has dimension(s) <= 0",
-		NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"PPM image data has dimension(s) <= 0", -1));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "DIMENSIONS", NULL);
 	return TCL_ERROR;
     }
     if ((maxIntensity <= 0) || (maxIntensity >= 256)) {
-	char buffer[TCL_INTEGER_SPACE];
-
-	sprintf(buffer, "%d", maxIntensity);
-	Tcl_AppendResult(interp,
-		"PPM image data has bad maximum intensity value ", buffer,
-		NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"PPM image data has bad maximum intensity value %d",
+		maxIntensity));
+	Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "INTENSITY", NULL);
 	return TCL_ERROR;
     }
 
@@ -538,7 +541,9 @@ StringReadPPM(
 	 */
 
 	if (block.pitch*height > dataSize) {
-	    Tcl_AppendResult(interp, "truncated PPM data", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "truncated PPM data", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "TRUNCATED", NULL);
 	    return TCL_ERROR;
 	}
 	block.pixelPtr = dataBuffer + srcX * block.pixelSize;
@@ -572,7 +577,9 @@ StringReadPPM(
 	}
 	if (dataSize < nBytes) {
 	    ckfree(pixelPtr);
-	    Tcl_AppendResult(interp, "truncated PPM data", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "truncated PPM data", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "TRUNCATED", NULL);
 	    return TCL_ERROR;
 	}
 	for (p=pixelPtr,count=nBytes ; count>0 ; count--,p++,dataBuffer++) {
diff --git a/generic/tkImgPhInstance.c b/generic/tkImgPhInstance.c
index 5429ee3..3097489 100644
--- a/generic/tkImgPhInstance.c
+++ b/generic/tkImgPhInstance.c
@@ -1068,8 +1068,7 @@ GetColorTable(
      * Allocate colors for this color table if necessary.
      */
 
-    if ((colorPtr->numColors == 0)
-	    && ((colorPtr->flags & BLACK_AND_WHITE) == 0)) {
+    if ((colorPtr->numColors == 0) && !(colorPtr->flags & BLACK_AND_WHITE)) {
 	AllocateColors(colorPtr);
     }
 }
@@ -1104,12 +1103,12 @@ FreeColorTable(
     }
 
     if (force) {
-	if ((colorPtr->flags & DISPOSE_PENDING) != 0) {
+	if (colorPtr->flags & DISPOSE_PENDING) {
 	    Tcl_CancelIdleCall(DisposeColorTable, colorPtr);
 	    colorPtr->flags &= ~DISPOSE_PENDING;
 	}
 	DisposeColorTable(colorPtr);
-    } else if ((colorPtr->flags & DISPOSE_PENDING) == 0) {
+    } else if (!(colorPtr->flags & DISPOSE_PENDING)) {
 	Tcl_DoWhenIdle(DisposeColorTable, colorPtr);
 	colorPtr->flags |= DISPOSE_PENDING;
     }
@@ -1813,11 +1812,11 @@ TkImgDitherInstance(
 		    }
 		    c = ((c + 2056) >> 4) - 128;
 
-		    if ((masterPtr->flags & COLOR_IMAGE) == 0) {
-			c += srcPtr[0];
-		    } else {
+		    if (masterPtr->flags & COLOR_IMAGE) {
 			c += (unsigned) (srcPtr[0] * 11 + srcPtr[1] * 16
 				+ srcPtr[2] * 5 + 16) >> 5;
+		    } else {
+			c += srcPtr[0];
 		    }
 		    srcPtr += 4;
 
@@ -1886,11 +1885,11 @@ TkImgDitherInstance(
 		    }
 		    c = ((c + 2056) >> 4) - 128;
 
-		    if ((masterPtr->flags & COLOR_IMAGE) == 0) {
-			c += srcPtr[0];
-		    } else {
+		    if (masterPtr->flags & COLOR_IMAGE) {
 			c += (unsigned)(srcPtr[0] * 11 + srcPtr[1] * 16
 				+ srcPtr[2] * 5 + 16) >> 5;
+		    } else {
+			c += srcPtr[0];
 		    }
 		    srcPtr += 4;
 
diff --git a/generic/tkImgPhoto.c b/generic/tkImgPhoto.c
index 5b172f1..ce160a4 100644
--- a/generic/tkImgPhoto.c
+++ b/generic/tkImgPhoto.c
@@ -504,7 +504,7 @@ ImgPhotoCmd(
 		     * TODO: Modifying result is bad!
 		     */
 
-		    Tcl_ListObjAppendElement(interp, Tcl_GetObjResult(interp),
+		    Tcl_ListObjAppendElement(NULL, Tcl_GetObjResult(interp),
 			    masterPtr->dataString);
 		} else {
 		    Tcl_AppendResult(interp, " {}", NULL);
@@ -518,7 +518,7 @@ ImgPhotoCmd(
 		     * TODO: Modifying result is bad!
 		     */
 
-		    Tcl_ListObjAppendElement(interp, Tcl_GetObjResult(interp),
+		    Tcl_ListObjAppendElement(NULL, Tcl_GetObjResult(interp),
 			    masterPtr->format);
 		} else {
 		    Tcl_AppendResult(interp, " {}", NULL);
@@ -562,17 +562,21 @@ ImgPhotoCmd(
 
 	srcHandle = Tk_FindPhoto(interp, Tcl_GetString(options.name));
 	if (srcHandle == NULL) {
-	    Tcl_AppendResult(interp, "image \"",
-		    Tcl_GetString(options.name), "\" doesn't",
-		    " exist or is not a photo image", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "image \"%s\" doesn't exist or is not a photo image",
+		    Tcl_GetString(options.name)));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "PHOTO",
+		    Tcl_GetString(options.name), NULL);
 	    return TCL_ERROR;
 	}
 	Tk_PhotoGetImage(srcHandle, &block);
 	if ((options.fromX2 > block.width) || (options.fromY2 > block.height)
 		|| (options.fromX2 > block.width)
 		|| (options.fromY2 > block.height)) {
-	    Tcl_AppendResult(interp, "coordinates for -from option extend ",
-		    "outside source image", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "coordinates for -from option extend outside source image",
+		    -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "BAD_FROM", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -624,8 +628,9 @@ ImgPhotoCmd(
 	if (options.options & OPT_SHRINK) {
 	    if (ImgPhotoSetSize(masterPtr, options.toX2,
 		    options.toY2) != TCL_OK) {
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, TK_PHOTO_ALLOC_FAILURE_MESSAGE, NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			TK_PHOTO_ALLOC_FAILURE_MESSAGE, -1));
+		Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -672,8 +677,9 @@ ImgPhotoCmd(
 		|| (options.fromY > masterPtr->height)
 		|| (options.fromX2 > masterPtr->width)
 		|| (options.fromY2 > masterPtr->height)) {
-	    Tcl_AppendResult(interp, "coordinates for -from option extend ",
-		    "outside image", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "coordinates for -from option extend outside image", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "BAD_FROM", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -681,7 +687,7 @@ ImgPhotoCmd(
 	 * Fill in default values for unspecified parameters.
 	 */
 
-	if (((options.options & OPT_FROM) == 0) || (options.fromX2 < 0)) {
+	if (!(options.options & OPT_FROM) || (options.fromX2 < 0)) {
 	    options.fromX2 = masterPtr->width;
 	    options.fromY2 = masterPtr->height;
 	}
@@ -719,9 +725,12 @@ ImgPhotoCmd(
 		}
 	    }
 	    if (stringWriteProc == NULL) {
-		Tcl_AppendResult(interp, "image string format \"",
-			Tcl_GetString(options.format), "\" is ",
-			(matched ? "not supported" : "unknown"), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"image string format \"%s\" is %s",
+			Tcl_GetString(options.format),
+			(matched ? "not supported" : "unknown")));
+		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "PHOTO_FORMAT",
+			Tcl_GetString(options.format), NULL);
 		return TCL_ERROR;
 	    }
 	} else {
@@ -770,7 +779,7 @@ ImgPhotoCmd(
 	 * photo get command - first parse and check parameters.
 	 */
 
-	char string[TCL_INTEGER_SPACE * 3];
+	Tcl_Obj *channels[3];
 
 	if (objc != 4) {
 	    Tcl_WrongNumArgs(interp, 2, objv, "x y");
@@ -782,8 +791,11 @@ ImgPhotoCmd(
 	}
 	if ((x < 0) || (x >= masterPtr->width)
 		|| (y < 0) || (y >= masterPtr->height)) {
-	    Tcl_AppendResult(interp, Tcl_GetString(objv[0]), " get: ",
-		    "coordinates out of range", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "%s get: coordinates out of range",
+		    Tcl_GetString(objv[0])));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "COORDINATES",
+		    NULL);
 	    return TCL_ERROR;
 	}
 
@@ -792,9 +804,10 @@ ImgPhotoCmd(
 	 */
 
 	pixelPtr = masterPtr->pix32 + (y * masterPtr->width + x) * 4;
-	sprintf(string, "%d %d %d", pixelPtr[0], pixelPtr[1],
-		pixelPtr[2]);
-	Tcl_AppendResult(interp, string, NULL);
+	channels[0] = Tcl_NewIntObj(pixelPtr[0]);
+	channels[1] = Tcl_NewIntObj(pixelPtr[1]);
+	channels[2] = Tcl_NewIntObj(pixelPtr[2]);
+	Tcl_SetObjResult(interp, Tcl_NewListObj(3, channels));
 	return TCL_OK;
     }
 
@@ -820,7 +833,7 @@ ImgPhotoCmd(
 		&imageHeight, &oldformat) == TCL_OK) {
 	    Tcl_Obj *format, *data;
 
-	    if (((options.options & OPT_TO) == 0) || (options.toX2 < 0)) {
+	    if (!(options.options & OPT_TO) || (options.toX2 < 0)) {
 		options.toX2 = options.toX + imageWidth;
 		options.toY2 = options.toY + imageHeight;
 	    }
@@ -876,8 +889,11 @@ ImgPhotoCmd(
 		pixelPtr = ckalloc(dataWidth * dataHeight * 3);
 		block.pixelPtr = pixelPtr;
 	    } else if (listObjc != dataWidth) {
-		Tcl_AppendResult(interp, "all elements of color list must",
-			" have the same number of elements", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"all elements of color list must have the same"
+			" number of elements", -1));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO",
+			"NON_RECTANGULAR", NULL);
 		break;
 	    }
 
@@ -920,8 +936,9 @@ ImgPhotoCmd(
 
 		if (!TkParseColor(Tk_Display(tkwin), Tk_Colormap(tkwin),
 			colorString, &color)) {
-		    Tcl_AppendResult(interp, "can't parse color \"",
-			    colorString, "\"", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "can't parse color \"%s\"", colorString));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "COLOR", NULL);
 		    break;
 		}
 		*pixelPtr++ = color.red >> 8;
@@ -992,8 +1009,9 @@ ImgPhotoCmd(
 	 */
 
 	if (Tcl_IsSafe(interp)) {
-	    Tcl_AppendResult(interp, "can't get image from a file in a",
-		    " safe interpreter", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't get image from a file in a safe interpreter", -1));
+	    Tcl_SetErrorCode(interp, "TK", "SAFE", "PHOTO_FILE", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1031,12 +1049,14 @@ ImgPhotoCmd(
 	if ((options.fromX > imageWidth) || (options.fromY > imageHeight)
 		|| (options.fromX2 > imageWidth)
 		|| (options.fromY2 > imageHeight)) {
-	    Tcl_AppendResult(interp, "coordinates for -from option extend ",
-		    "outside source image", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "coordinates for -from option extend outside source image",
+		    -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "BAD_FROM", NULL);
 	    Tcl_Close(NULL, chan);
 	    return TCL_ERROR;
 	}
-	if (((options.options & OPT_FROM) == 0) || (options.fromX2 < 0)) {
+	if (!(options.options & OPT_FROM) || (options.fromX2 < 0)) {
 	    width = imageWidth - options.fromX;
 	    height = imageHeight - options.fromY;
 	} else {
@@ -1052,7 +1072,9 @@ ImgPhotoCmd(
 	    if (ImgPhotoSetSize(masterPtr, options.toX + width,
 		    options.toY + height) != TCL_OK) {
 		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, TK_PHOTO_ALLOC_FAILURE_MESSAGE, NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			TK_PHOTO_ALLOC_FAILURE_MESSAGE, -1));
+		Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -1143,8 +1165,11 @@ ImgPhotoCmd(
 	    }
 	    if ((x < 0) || (x >= masterPtr->width)
 		    || (y < 0) || (y >= masterPtr->height)) {
-		Tcl_AppendResult(interp, Tcl_GetString(objv[0]),
-			" transparency get: coordinates out of range", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"%s transparency get: coordinates out of range",
+			Tcl_GetString(objv[0])));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "COORDINATES",
+			NULL);
 		return TCL_ERROR;
 	    }
 
@@ -1180,8 +1205,11 @@ ImgPhotoCmd(
 	    }
 	    if ((x < 0) || (x >= masterPtr->width)
 		|| (y < 0) || (y >= masterPtr->height)) {
-		Tcl_AppendResult(interp, Tcl_GetString(objv[0]),
-			" transparency set: coordinates out of range", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"%s transparency set: coordinates out of range",
+			Tcl_GetString(objv[0])));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "COORDINATES",
+			NULL);
 		return TCL_ERROR;
 	    }
 
@@ -1244,8 +1272,9 @@ ImgPhotoCmd(
 	 */
 
 	if (Tcl_IsSafe(interp)) {
-	    Tcl_AppendResult(interp, "can't write image to a file in a",
-		    " safe interpreter", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't write image to a file in a safe interpreter", -1));
+	    Tcl_SetErrorCode(interp, "TK", "SAFE", "PHOTO_FILE", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1270,8 +1299,9 @@ ImgPhotoCmd(
 		|| (options.fromY > masterPtr->height)
 		|| (options.fromX2 > masterPtr->width)
 		|| (options.fromY2 > masterPtr->height)) {
-	    Tcl_AppendResult(interp, "coordinates for -from option extend ",
-		    "outside image", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "coordinates for -from option extend outside image", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "BAD_FROM", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1338,19 +1368,19 @@ ImgPhotoCmd(
 	}
 	if (imageFormat == NULL) {
 	    if (fmtString == NULL) {
-		Tcl_AppendResult(interp, "no available image file format ",
-			"has file writing capability", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"no available image file format has file writing"
+			" capability", -1));
 	    } else if (!matched) {
-		Tcl_AppendResult(interp, "image file format \"",
-			fmtString, "\" is unknown", NULL);
-		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "PHOTO_FORMAT",
-			fmtString, NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"image file format \"%s\" is unknown", fmtString));
 	    } else {
-		Tcl_AppendResult(interp, "image file format \"",
-			fmtString, "\" has no file writing capability", NULL);
-		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "PHOTO_FORMAT",
-			fmtString, NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"image file format \"%s\" has no file writing capability",
+			fmtString));
 	    }
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "PHOTO_FORMAT",
+		    fmtString, NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1441,10 +1471,16 @@ ParseSubcommandOptions(
     int objc,			/* Number of arguments in objv[]. */
     Tcl_Obj *const objv[])	/* Arguments to be parsed. */
 {
+    static const char *const compositingRules[] = {
+	"overlay", "set",	/* Note that these must match the
+				 * TK_PHOTO_COMPOSITE_* constants. */
+	NULL
+    };
     int index, c, bit, currentBit, length;
     int values[4], numValues, maxValues, argIndex;
-    const char *option;
+    const char *option, *expandedOption, *needed;
     const char *const *listPtr;
+    Tcl_Obj *msgObj;
 
     for (index = *optIndexPtr; index < objc; *optIndexPtr = ++index) {
 	/*
@@ -1452,7 +1488,7 @@ ParseSubcommandOptions(
 	 * optPtr->name.
 	 */
 
-	option = Tcl_GetStringFromObj(objv[index], &length);
+	expandedOption = option = Tcl_GetStringFromObj(objv[index], &length);
 	if (option[0] != '-') {
 	    if (optPtr->name == NULL) {
 		optPtr->name = objv[index];
@@ -1471,9 +1507,9 @@ ParseSubcommandOptions(
 	for (listPtr = optionNames; *listPtr != NULL; ++listPtr) {
 	    if ((c == *listPtr[0])
 		    && (strncmp(option, *listPtr, (size_t) length) == 0)) {
+		expandedOption = *listPtr;
 		if (bit != 0) {
-		    bit = 0;	/* An ambiguous option. */
-		    break;
+		    goto unknownOrAmbiguousOption;
 		}
 		bit = currentBit;
 	    }
@@ -1485,24 +1521,8 @@ ParseSubcommandOptions(
 	 * in the interpreter and return.
 	 */
 
-	if ((allowedOptions & bit) == 0) {
-	    Tcl_AppendResult(interp, "unrecognized option \"",
-	    	    Tcl_GetString(objv[index]),
-		    "\": must be ", NULL);
-	    bit = 1;
-	    for (listPtr = optionNames; *listPtr != NULL; ++listPtr) {
-		if ((allowedOptions & bit) != 0) {
-		    if ((allowedOptions & (bit - 1)) != 0) {
-			Tcl_AppendResult(interp, ", ", NULL);
-			if ((allowedOptions & ~((bit << 1) - 1)) == 0) {
-			    Tcl_AppendResult(interp, "or ", NULL);
-			}
-		    }
-		    Tcl_AppendResult(interp, *listPtr, NULL);
-		}
-		bit <<= 1;
-	    }
-	    return TCL_ERROR;
+	if (!(allowedOptions & bit)) {
+	    goto unknownOrAmbiguousOption;
 	}
 
 	/*
@@ -1515,16 +1535,13 @@ ParseSubcommandOptions(
 	     * The -background option takes a single XColor value.
 	     */
 
-	    if (index + 1 < objc) {
-		*optIndexPtr = ++index;
-		optPtr->background = Tk_GetColor(interp, Tk_MainWindow(interp),
-			Tk_GetUid(Tcl_GetString(objv[index])));
-		if (!optPtr->background) {
-		    return TCL_ERROR;
-		}
-	    } else {
-		Tcl_AppendResult(interp, "the \"-background\" option ",
-			"requires a value", NULL);
+	    if (index + 1 >= objc) {
+		goto oneValueRequired;
+	    }
+	    *optIndexPtr = ++index;
+	    optPtr->background = Tk_GetColor(interp, Tk_MainWindow(interp),
+		    Tk_GetUid(Tcl_GetString(objv[index])));
+	    if (!optPtr->background) {
 		return TCL_ERROR;
 	    }
 	} else if (bit == OPT_FORMAT) {
@@ -1533,45 +1550,31 @@ ParseSubcommandOptions(
 	     * parsing this is outside the scope of this function.
 	     */
 
-	    if (index + 1 < objc) {
-		*optIndexPtr = ++index;
-		optPtr->format = objv[index];
-	    } else {
-		Tcl_AppendResult(interp, "the \"-format\" option ",
-			"requires a value", NULL);
-		return TCL_ERROR;
+	    if (index + 1 >= objc) {
+		goto oneValueRequired;
 	    }
+	    *optIndexPtr = ++index;
+	    optPtr->format = objv[index];
 	} else if (bit == OPT_COMPOSITE) {
 	    /*
 	     * The -compositingrule option takes a single value from a
 	     * well-known set.
 	     */
 
-	    if (index + 1 < objc) {
-		/*
-		 * Note that these must match the TK_PHOTO_COMPOSITE_*
-		 * constants.
-		 */
-
-		static const char *const compositingRules[] = {
-		    "overlay", "set", NULL
-		};
-
-		index++;
-		if (Tcl_GetIndexFromObj(interp, objv[index], compositingRules,
-			"compositing rule", 0, &optPtr->compositingRule)
-			!= TCL_OK) {
-		    return TCL_ERROR;
-		}
-		*optIndexPtr = index;
-	    } else {
-		Tcl_AppendResult(interp, "the \"-compositingrule\" option ",
-			"requires a value", NULL);
+	    if (index + 1 >= objc) {
+		goto oneValueRequired;
+	    }
+	    index++;
+	    if (Tcl_GetIndexFromObj(interp, objv[index], compositingRules,
+		    "compositing rule", 0, &optPtr->compositingRule)
+		    != TCL_OK) {
 		return TCL_ERROR;
 	    }
+	    *optIndexPtr = index;
 	} else if ((bit != OPT_SHRINK) && (bit != OPT_GRAYSCALE)) {
 	    const char *val;
-	    maxValues = ((bit == OPT_FROM) || (bit == OPT_TO))? 4: 2;
+
+	    maxValues = ((bit == OPT_FROM) || (bit == OPT_TO)) ? 4 : 2;
 	    argIndex = index + 1;
 	    for (numValues = 0; numValues < maxValues; ++numValues) {
 		if (argIndex >= objc) {
@@ -1591,10 +1594,7 @@ ParseSubcommandOptions(
 	    }
 
 	    if (numValues == 0) {
-		Tcl_AppendResult(interp, "the \"", option, "\" option ",
-			 "requires one ", maxValues == 2? "or two": "to four",
-			 " integer values", NULL);
-		return TCL_ERROR;
+		goto manyValuesRequired;
 	    }
 	    *optIndexPtr = (index += numValues);
 
@@ -1618,9 +1618,8 @@ ParseSubcommandOptions(
 	    case OPT_FROM:
 		if ((values[0] < 0) || (values[1] < 0) || ((numValues > 2)
 			&& ((values[2] < 0) || (values[3] < 0)))) {
-		    Tcl_AppendResult(interp, "value(s) for the -from",
-			    " option must be non-negative", NULL);
-		    return TCL_ERROR;
+		    needed = "non-negative";
+		    goto numberOutOfRange;
 		}
 		if (numValues <= 2) {
 		    optPtr->fromX = values[0];
@@ -1641,9 +1640,8 @@ ParseSubcommandOptions(
 	    case OPT_TO:
 		if ((values[0] < 0) || (values[1] < 0) || ((numValues > 2)
 			&& ((values[2] < 0) || (values[3] < 0)))) {
-		    Tcl_AppendResult(interp, "value(s) for the -to",
-			    " option must be non-negative", NULL);
-		    return TCL_ERROR;
+		    needed = "non-negative";
+		    goto numberOutOfRange;
 		}
 		if (numValues <= 2) {
 		    optPtr->toX = values[0];
@@ -1659,9 +1657,8 @@ ParseSubcommandOptions(
 		break;
 	    case OPT_ZOOM:
 		if ((values[0] <= 0) || (values[1] <= 0)) {
-		    Tcl_AppendResult(interp, "value(s) for the -zoom",
-			    " option must be positive", NULL);
-		    return TCL_ERROR;
+		    needed = "positive";
+		    goto numberOutOfRange;
 		}
 		optPtr->zoomX = values[0];
 		optPtr->zoomY = values[1];
@@ -1675,8 +1672,50 @@ ParseSubcommandOptions(
 
 	optPtr->options |= bit;
     }
-
     return TCL_OK;
+
+    /*
+     * Exception generation.
+     */
+
+  oneValueRequired:
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "the \"%s\" option requires a value", expandedOption));
+    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "MISSING_VALUE", NULL);
+    return TCL_ERROR;
+
+  manyValuesRequired:
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "the \"%s\" option requires one %s integer values",
+	    expandedOption, (maxValues == 2) ? "or two": "to four"));
+    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "MISSING_VALUE", NULL);
+    return TCL_ERROR;
+
+  numberOutOfRange:
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "value(s) for the %s option must be %s", expandedOption, needed));
+    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "BAD_VALUE", NULL);
+    return TCL_ERROR;
+
+  unknownOrAmbiguousOption:
+    msgObj = Tcl_ObjPrintf("unrecognized option \"%s\": must be ", option);
+    bit = 1;
+    for (listPtr = optionNames; *listPtr != NULL; ++listPtr) {
+	if (allowedOptions & bit) {
+	    if (allowedOptions & (bit - 1)) {
+		if (allowedOptions & ~((bit << 1) - 1)) {
+		    Tcl_AppendToObj(msgObj, ", ", -1);
+		} else {
+		    Tcl_AppendToObj(msgObj, ", or ", -1);
+		}
+	    }
+	    Tcl_AppendToObj(msgObj, *listPtr, -1);
+	}
+	bit <<= 1;
+    }
+    Tcl_SetObjResult(interp, msgObj);
+    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO", "BAD_OPTION", NULL);
+    return TCL_ERROR;
 }
 
 /*
@@ -1730,8 +1769,10 @@ ImgPhotoConfigureMaster(
 		    j--;
 		} else {
 		    ckfree(args);
-		    Tcl_AppendResult(interp,
-			    "value for \"-data\" missing", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "value for \"-data\" missing", -1));
+		    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO",
+			    "MISSING_VALUE", NULL);
 		    return TCL_ERROR;
 		}
 	    } else if ((args[j][1] == 'f') &&
@@ -1741,8 +1782,10 @@ ImgPhotoConfigureMaster(
 		    j--;
 		} else {
 		    ckfree(args);
-		    Tcl_AppendResult(interp,
-			    "value for \"-format\" missing", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "value for \"-format\" missing", -1));
+		    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO",
+			    "MISSING_VALUE", NULL);
 		    return TCL_ERROR;
 		}
 	    }
@@ -1832,8 +1875,9 @@ ImgPhotoConfigureMaster(
 
     if (ImgPhotoSetSize(masterPtr, masterPtr->width,
 	    masterPtr->height) != TCL_OK) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, TK_PHOTO_ALLOC_FAILURE_MESSAGE, NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		TK_PHOTO_ALLOC_FAILURE_MESSAGE, -1));
+	Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 	goto errorExit;
     }
 
@@ -1851,8 +1895,10 @@ ImgPhotoConfigureMaster(
 
 	if (Tcl_IsSafe(interp)) {
 	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp,
-		    "can't get image from a file in a safe interpreter", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't get image from a file in a safe interpreter",
+		    -1));
+	    Tcl_SetErrorCode(interp, "TK", "SAFE", "PHOTO_FILE", NULL);
 	    goto errorExit;
 	}
 
@@ -1876,8 +1922,9 @@ ImgPhotoConfigureMaster(
 	result = ImgPhotoSetSize(masterPtr, imageWidth, imageHeight);
 	if (result != TCL_OK) {
 	    Tcl_Close(NULL, chan);
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, TK_PHOTO_ALLOC_FAILURE_MESSAGE, NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    TK_PHOTO_ALLOC_FAILURE_MESSAGE, -1));
+	    Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 	    goto errorExit;
 	}
 	tempformat = masterPtr->format;
@@ -1906,8 +1953,9 @@ ImgPhotoConfigureMaster(
 	    goto errorExit;
 	}
 	if (ImgPhotoSetSize(masterPtr, imageWidth, imageHeight) != TCL_OK) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, TK_PHOTO_ALLOC_FAILURE_MESSAGE, NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    TK_PHOTO_ALLOC_FAILURE_MESSAGE, -1));
+	    Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 	    goto errorExit;
 	}
 	tempformat = masterPtr->format;
@@ -2351,8 +2399,11 @@ MatchFileFormat(
 	    }
 	    matched = 1;
 	    if (formatPtr->fileMatchProc == NULL) {
-		Tcl_AppendResult(interp, "-file option isn't supported for ",
-			formatString, " images", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"-file option isn't supported for %s images",
+			formatString));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO",
+			"NOT_FILE_FORMAT", NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -2382,8 +2433,11 @@ MatchFileFormat(
 		}
 		matched = 1;
 		if (formatPtr->fileMatchProc == NULL) {
-		    Tcl_AppendResult(interp, "-file option isn't supported",
-			    " for ", formatString, " images", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "-file option isn't supported for %s images",
+			    formatString));
+		    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO",
+			    "NOT_FILE_FORMAT", NULL);
 		    return TCL_ERROR;
 		}
 	    }
@@ -2405,12 +2459,17 @@ MatchFileFormat(
 
     if (formatPtr == NULL) {
 	if ((formatObj != NULL) && !matched) {
-	    Tcl_AppendResult(interp, "image file format \"", formatString,
-		    "\" is not supported", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "image file format \"%s\" is not supported",
+		    formatString));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "PHOTO_FORMAT",
+		    formatString, NULL);
 	} else {
-	    Tcl_AppendResult(interp,
-		    "couldn't recognize data in image file \"", fileName, "\"",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "couldn't recognize data in image file \"%s\"",
+		    fileName));
+	    Tcl_SetErrorCode(interp, "TK", "PHOTO", "IMAGE",
+		    "UNRECOGNIZED_DATA", NULL);
 	}
 	return TCL_ERROR;
     }
@@ -2480,8 +2539,11 @@ MatchStringFormat(
 	    }
 	    matched = 1;
 	    if (formatPtr->stringMatchProc == NULL) {
-		Tcl_AppendResult(interp, "-data option isn't supported for ",
-			formatString, " images", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"-data option isn't supported for %s images",
+			formatString));
+		Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO",
+			"NOT_DATA_FORMAT", NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -2504,8 +2566,11 @@ MatchStringFormat(
 		}
 		matched = 1;
 		if (formatPtr->stringMatchProc == NULL) {
-		    Tcl_AppendResult(interp, "-data option isn't supported",
-			    " for ", formatString, " images", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "-data option isn't supported for %s images",
+			    formatString));
+		    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO",
+			    "NOT_DATA_FORMAT", NULL);
 		    return TCL_ERROR;
 		}
 	    }
@@ -2521,10 +2586,15 @@ MatchStringFormat(
     }
     if (formatPtr == NULL) {
 	if ((formatObj != NULL) && !matched) {
-	    Tcl_AppendResult(interp, "image format \"", formatString,
-		    "\" is not supported", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "image format \"%s\" is not supported", formatString));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "PHOTO_FORMAT",
+		    formatString, NULL);
 	} else {
-	    Tcl_AppendResult(interp, "couldn't recognize image data", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "couldn't recognize image data", -1));
+	    Tcl_SetErrorCode(interp, "TK", "IMAGE", "PHOTO",
+		    "UNRECOGNIZED_DATA", NULL);
 	}
 	return TCL_ERROR;
     }
@@ -2641,8 +2711,9 @@ Tk_PhotoPutBlock(
 	if (ImgPhotoSetSize(masterPtr, MAX(xEnd, masterPtr->width),
 		MAX(yEnd, masterPtr->height)) == TCL_ERROR) {
 	    if (interp != NULL) {
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, TK_PHOTO_ALLOC_FAILURE_MESSAGE, NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			TK_PHOTO_ALLOC_FAILURE_MESSAGE, -1));
+		Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 	    }
 	    return TCL_ERROR;
 	}
@@ -3037,8 +3108,9 @@ Tk_PhotoPutZoomedBlock(
 	if (ImgPhotoSetSize(masterPtr, MAX(xEnd, masterPtr->width),
 		MAX(yEnd, masterPtr->height)) == TCL_ERROR) {
 	    if (interp != NULL) {
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, TK_PHOTO_ALLOC_FAILURE_MESSAGE, NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			TK_PHOTO_ALLOC_FAILURE_MESSAGE, -1));
+		Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 	    }
 	    return TCL_ERROR;
 	}
@@ -3435,8 +3507,9 @@ Tk_PhotoExpand(
 	if (ImgPhotoSetSize(masterPtr, MAX(width, masterPtr->width),
 		MAX(height, masterPtr->height)) == TCL_ERROR) {
 	    if (interp != NULL) {
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, TK_PHOTO_ALLOC_FAILURE_MESSAGE, NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			TK_PHOTO_ALLOC_FAILURE_MESSAGE, -1));
+		Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 	    }
 	    return TCL_ERROR;
 	}
@@ -3509,8 +3582,9 @@ Tk_PhotoSetSize(
     if (ImgPhotoSetSize(masterPtr, ((width > 0) ? width: masterPtr->width),
 	    ((height > 0) ? height: masterPtr->height)) == TCL_ERROR) {
 	if (interp != NULL) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, TK_PHOTO_ALLOC_FAILURE_MESSAGE, NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    TK_PHOTO_ALLOC_FAILURE_MESSAGE, -1));
+	    Tcl_SetErrorCode(interp, "TK", "MALLOC", NULL);
 	}
 	return TCL_ERROR;
     }
diff --git a/generic/tkInt.h b/generic/tkInt.h
index 01cc9cb..21b882c 100644
--- a/generic/tkInt.h
+++ b/generic/tkInt.h
@@ -1170,7 +1170,7 @@ MODULE_SCOPE void	TkpBuildRegionFromAlphaData(TkRegion region,
 			    unsigned x, unsigned y, unsigned width,
 			    unsigned height, unsigned char *dataPtr,
 			    unsigned pixelStride, unsigned lineStride);
-MODULE_SCOPE void	TkPrintPadAmount(Tcl_Interp *interp,
+MODULE_SCOPE void	TkAppendPadAmount(Tcl_Obj *bufferObj,
 			    const char *buffer, int pad1, int pad2);
 MODULE_SCOPE int	TkParsePadAmount(Tcl_Interp *interp,
 			    Tk_Window tkwin, Tcl_Obj *objPtr,
diff --git a/generic/tkListbox.c b/generic/tkListbox.c
index 7faa44b..620f82f 100644
--- a/generic/tkListbox.c
+++ b/generic/tkListbox.c
@@ -168,6 +168,13 @@ typedef struct {
 } Listbox;
 
 /*
+ * How to encode the keys for the hash tables used to store what items are
+ * selected and what the attributes are.
+ */
+
+#define KEY(i)		((char *) INT2PTR(i))
+
+/*
  * ItemAttr structures are used to store item configuration information for
  * the items in a listbox
  */
@@ -437,8 +444,8 @@ static void		MigrateHashEntries(Tcl_HashTable *table,
 static const Tk_ClassProcs listboxClass = {
     sizeof(Tk_ClassProcs),	/* size */
     ListboxWorldChanged,	/* worldChangedProc */
-    NULL,					/* createProc */
-    NULL					/* modalProc */
+    NULL,			/* createProc */
+    NULL			/* modalProc */
 };
 
 /*
@@ -480,8 +487,7 @@ Tk_ListboxObjCmd(
 	return TCL_ERROR;
     }
 
-    optionTables = (ListboxOptionTables *)
-	Tcl_GetAssocData(interp, "ListboxOptionTables", NULL);
+    optionTables = Tcl_GetAssocData(interp, "ListboxOptionTables", NULL);
     if (optionTables == NULL) {
 	/*
 	 * We haven't created the option tables for this widget class yet. Do
@@ -515,7 +521,7 @@ Tk_ListboxObjCmd(
      */
 
     listPtr			 = ckalloc(sizeof(Listbox));
-    memset(listPtr, 0, (sizeof(Listbox)));
+    memset(listPtr, 0, sizeof(Listbox));
 
     listPtr->tkwin		 = tkwin;
     listPtr->display		 = Tk_Display(tkwin);
@@ -597,6 +603,7 @@ ListboxWidgetObjCmd(
     register Listbox *listPtr = clientData;
     int cmdIndex, index;
     int result = TCL_OK;
+    Tcl_Obj *objPtr;
 
     if (objc < 2) {
 	Tcl_WrongNumArgs(interp, 1, objv, "option ?arg ...?");
@@ -661,9 +668,7 @@ ListboxWidgetObjCmd(
 	result = ListboxBboxSubCmd(interp, listPtr, index);
 	break;
 
-    case COMMAND_CGET: {
-	Tcl_Obj *objPtr;
-
+    case COMMAND_CGET:
 	if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 2, objv, "option");
 	    result = TCL_ERROR;
@@ -679,11 +684,8 @@ ListboxWidgetObjCmd(
 	Tcl_SetObjResult(interp, objPtr);
 	result = TCL_OK;
 	break;
-    }
-
-    case COMMAND_CONFIGURE: {
-	Tcl_Obj *objPtr;
 
+    case COMMAND_CONFIGURE:
 	if (objc <= 3) {
 	    objPtr = Tk_GetOptionInfo(interp, (char *) listPtr,
 		    listPtr->optionTable,
@@ -698,10 +700,8 @@ ListboxWidgetObjCmd(
 	    result = ConfigureListbox(interp, listPtr, objc-2, objv+2, 0);
 	}
 	break;
-    }
 
     case COMMAND_CURSELECTION: {
-	char indexStringRep[TCL_INTEGER_SPACE];
 	int i;
 
 	if (objc != 2) {
@@ -718,12 +718,13 @@ ListboxWidgetObjCmd(
 	 * selected.
 	 */
 
+	objPtr = Tcl_NewObj();
 	for (i = 0; i < listPtr->nElements; i++) {
-	    if (Tcl_FindHashEntry(listPtr->selection, (char *) INT2PTR(i))) {
-		sprintf(indexStringRep, "%d", i);
-		Tcl_AppendElement(interp, indexStringRep);
+	    if (Tcl_FindHashEntry(listPtr->selection, KEY(i))) {
+		Tcl_ListObjAppendElement(NULL, objPtr, Tcl_NewIntObj(i));
 	    }
 	}
+	Tcl_SetObjResult(interp, objPtr);
 	result = TCL_OK;
 	break;
     }
@@ -857,7 +858,6 @@ ListboxWidgetObjCmd(
 	break;
 
     case COMMAND_ITEMCGET: {
-	Tcl_Obj *objPtr;
 	ItemAttr *attrPtr;
 
 	if (objc != 4) {
@@ -872,8 +872,10 @@ ListboxWidgetObjCmd(
 	}
 
 	if (index < 0 || index >= listPtr->nElements) {
-	    Tcl_AppendResult(interp, "item number \"",
-		    Tcl_GetString(objv[2]), "\" out of range", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "item number \"%s\" out of range",
+		    Tcl_GetString(objv[2])));
+	    Tcl_SetErrorCode(interp, "TK", "LISTBOX", "ITEM_INDEX", NULL);
 	    result = TCL_ERROR;
 	    break;
 	}
@@ -892,7 +894,6 @@ ListboxWidgetObjCmd(
     }
 
     case COMMAND_ITEMCONFIGURE: {
-	Tcl_Obj *objPtr;
 	ItemAttr *attrPtr;
 
 	if (objc < 3) {
@@ -908,8 +909,10 @@ ListboxWidgetObjCmd(
 	}
 
 	if (index < 0 || index >= listPtr->nElements) {
-	    Tcl_AppendResult(interp, "item number \"", Tcl_GetString(objv[2]),
-		    "\" out of range", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "item number \"%s\" out of range",
+		    Tcl_GetString(objv[2])));
+	    Tcl_SetErrorCode(interp, "TK", "LISTBOX", "ITEM_INDEX", NULL);
 	    result = TCL_ERROR;
 	    break;
 	}
@@ -922,10 +925,9 @@ ListboxWidgetObjCmd(
 	    if (objPtr == NULL) {
 		result = TCL_ERROR;
 		break;
-	    } else {
-		Tcl_SetObjResult(interp, objPtr);
-		result = TCL_OK;
 	    }
+	    Tcl_SetObjResult(interp, objPtr);
+	    result = TCL_OK;
 	} else {
 	    result = ConfigureListboxItem(interp, listPtr, attrPtr,
 		    objc-3, objv+3, index);
@@ -1007,7 +1009,7 @@ ListboxWidgetObjCmd(
 	}
 	diff = listPtr->topIndex - index;
 	if (diff > 0) {
-	    if (diff <= (listPtr->fullLines/3)) {
+	    if (diff <= listPtr->fullLines / 3) {
 		ChangeListboxView(listPtr, index);
 	    } else {
 		ChangeListboxView(listPtr, index - (listPtr->fullLines-1)/2);
@@ -1015,7 +1017,7 @@ ListboxWidgetObjCmd(
 	} else {
 	    diff = index - (listPtr->topIndex + listPtr->fullLines - 1);
 	    if (diff > 0) {
-		if (diff <= (listPtr->fullLines/3)) {
+		if (diff <= listPtr->fullLines / 3) {
 		    ChangeListboxView(listPtr, listPtr->topIndex + diff);
 		} else {
 		    ChangeListboxView(listPtr, index-(listPtr->fullLines-1)/2);
@@ -1090,7 +1092,7 @@ ListboxBboxSubCmd(
      */
 
     if ((listPtr->topIndex <= index) && (index < lastVisibleIndex)) {
-	Tcl_Obj *el;
+	Tcl_Obj *el, *results[4];
 	const char *stringRep;
 	int pixelWidth, stringLen, x, y, result;
 	Tk_FontMetrics fm;
@@ -1111,8 +1113,11 @@ ListboxBboxSubCmd(
 	x = listPtr->inset + listPtr->selBorderWidth - listPtr->xOffset;
 	y = ((index - listPtr->topIndex)*listPtr->lineHeight)
 		+ listPtr->inset + listPtr->selBorderWidth;
-	Tcl_SetObjResult(interp, Tcl_ObjPrintf("%d %d %d %d",
-		x, y, pixelWidth, fm.linespace));
+	results[0] = Tcl_NewIntObj(x);
+	results[1] = Tcl_NewIntObj(y);
+	results[2] = Tcl_NewIntObj(pixelWidth);
+	results[3] = Tcl_NewIntObj(fm.linespace);
+	Tcl_SetObjResult(interp, Tcl_NewListObj(4, results));
     }
     return TCL_OK;
 }
@@ -1197,9 +1202,8 @@ ListboxSelectionSubCmd(
 	    Tcl_WrongNumArgs(interp, 3, objv, "index");
 	    return TCL_ERROR;
 	}
-	Tcl_SetObjResult(interp,
-		Tcl_NewBooleanObj((Tcl_FindHashEntry(listPtr->selection,
-			(char *) INT2PTR(first)) != NULL)));
+	Tcl_SetObjResult(interp, Tcl_NewBooleanObj(
+		Tcl_FindHashEntry(listPtr->selection, KEY(first)) != NULL));
 	result = TCL_OK;
 	break;
     case SELECTION_SET:
@@ -1232,43 +1236,45 @@ ListboxXviewSubCmd(
     int objc,			/* Number of arguments in the objv array */
     Tcl_Obj *const objv[])	/* Array of arguments to the procedure */
 {
-
-    int index, count, type, windowWidth, windowUnits;
+    int index, count, windowWidth, windowUnits;
     int offset = 0;		/* Initialized to stop gcc warnings. */
     double fraction;
 
     windowWidth = Tk_Width(listPtr->tkwin)
 	    - 2*(listPtr->inset + listPtr->selBorderWidth);
     if (objc == 2) {
+	Tcl_Obj *results[2];
+
 	if (listPtr->maxWidth == 0) {
-	    Tcl_SetResult(interp, "0.0 1.0", TCL_STATIC);
+	    results[0] = Tcl_NewDoubleObj(0.0);
+	    results[1] = Tcl_NewDoubleObj(1.0);
 	} else {
 	    double fraction2;
 
-	    fraction = listPtr->xOffset/((double) listPtr->maxWidth);
+	    fraction = listPtr->xOffset / (double) listPtr->maxWidth;
 	    fraction2 = (listPtr->xOffset + windowWidth)
-		    / ((double) listPtr->maxWidth);
+		    / (double) listPtr->maxWidth;
 	    if (fraction2 > 1.0) {
 		fraction2 = 1.0;
 	    }
-	    Tcl_SetObjResult(interp, Tcl_ObjPrintf("%g %g",
-		    fraction, fraction2));
+	    results[0] = Tcl_NewDoubleObj(fraction);
+	    results[1] = Tcl_NewDoubleObj(fraction2);
 	}
+	Tcl_SetObjResult(interp, Tcl_NewListObj(2, results));
     } else if (objc == 3) {
 	if (Tcl_GetIntFromObj(interp, objv[2], &index) != TCL_OK) {
 	    return TCL_ERROR;
 	}
 	ChangeListboxOffset(listPtr, index*listPtr->xScrollUnit);
     } else {
-	type = Tk_GetScrollInfoObj(interp, objc, objv, &fraction, &count);
-	switch (type) {
+	switch (Tk_GetScrollInfoObj(interp, objc, objv, &fraction, &count)) {
 	case TK_SCROLL_ERROR:
 	    return TCL_ERROR;
 	case TK_SCROLL_MOVETO:
 	    offset = (int) (fraction*listPtr->maxWidth + 0.5);
 	    break;
 	case TK_SCROLL_PAGES:
-	    windowUnits = windowWidth/listPtr->xScrollUnit;
+	    windowUnits = windowWidth / listPtr->xScrollUnit;
 	    if (windowUnits > 2) {
 		offset = listPtr->xOffset
 			+ count*listPtr->xScrollUnit*(windowUnits-2);
@@ -1308,12 +1314,15 @@ ListboxYviewSubCmd(
     int objc,			/* Number of arguments in the objv array */
     Tcl_Obj *const objv[])	/* Array of arguments to the procedure */
 {
-    int index, count, type;
+    int index, count;
     double fraction;
 
     if (objc == 2) {
+	Tcl_Obj *results[2];
+
 	if (listPtr->nElements == 0) {
-	    Tcl_SetResult(interp, "0.0 1.0", TCL_STATIC);
+	    results[0] = Tcl_NewDoubleObj(0.0);
+	    results[1] = Tcl_NewDoubleObj(1.0);
 	} else {
 	    double fraction2, numEls = (double) listPtr->nElements;
 
@@ -1322,17 +1331,17 @@ ListboxYviewSubCmd(
 	    if (fraction2 > 1.0) {
 		fraction2 = 1.0;
 	    }
-	    Tcl_SetObjResult(interp, Tcl_ObjPrintf("%g %g",
-		    fraction, fraction2));
+	    results[0] = Tcl_NewDoubleObj(fraction);
+	    results[1] = Tcl_NewDoubleObj(fraction2);
 	}
+	Tcl_SetObjResult(interp, Tcl_NewListObj(2, results));
     } else if (objc == 3) {
 	if (GetListboxIndex(interp, listPtr, objv[2], 0, &index) != TCL_OK) {
 	    return TCL_ERROR;
 	}
 	ChangeListboxView(listPtr, index);
     } else {
-	type = Tk_GetScrollInfoObj(interp, objc, objv, &fraction, &count);
-	switch (type) {
+	switch (Tk_GetScrollInfoObj(interp, objc, objv, &fraction, &count)) {
 	case TK_SCROLL_MOVETO:
 	    index = (int) (listPtr->nElements*fraction + 0.5);
 	    break;
@@ -1383,8 +1392,7 @@ ListboxGetItemAttributes(
     Tcl_HashEntry *entry;
     ItemAttr *attrs;
 
-    entry = Tcl_CreateHashEntry(listPtr->itemAttrTable,
-	    (char *) INT2PTR(index), &isNew);
+    entry = Tcl_CreateHashEntry(listPtr->itemAttrTable, KEY(index), &isNew);
     if (isNew) {
 	attrs = ckalloc(sizeof(ItemAttr));
 	attrs->border = NULL;
@@ -1910,7 +1918,7 @@ DisplayListbox(
 	 * special foreground/background colors.
 	 */
 
-	entry = Tcl_FindHashEntry(listPtr->itemAttrTable, (char *) INT2PTR(i));
+	entry = Tcl_FindHashEntry(listPtr->itemAttrTable, KEY(i));
 
 	/*
 	 * If the listbox is enabled, items may be drawn differently; they may
@@ -1919,7 +1927,7 @@ DisplayListbox(
 	 */
 
 	if (listPtr->state & STATE_NORMAL) {
-	    if (Tcl_FindHashEntry(listPtr->selection, (char *) INT2PTR(i))) {
+	    if (Tcl_FindHashEntry(listPtr->selection, KEY(i))) {
 		/*
 		 * Selected items are drawn differently.
 		 */
@@ -2001,8 +2009,7 @@ DisplayListbox(
 		}
 		/* Draw bottom bevel */
 		if (i + 1 == listPtr->nElements ||
-			Tcl_FindHashEntry(listPtr->selection,
-				(char *) INT2PTR(i + 1)) == NULL ) {
+			!Tcl_FindHashEntry(listPtr->selection, KEY(i + 1))) {
 		    Tk_3DHorizontalBevel(tkwin, pixmap, selectedBg, x-left,
 			    y + listPtr->lineHeight - listPtr->selBorderWidth,
 			    width+left+right, listPtr->selBorderWidth, 0, 0, 0,
@@ -2238,7 +2245,7 @@ ListboxComputeGeometry(
     width = listPtr->width;
     if (width <= 0) {
 	width = (listPtr->maxWidth + listPtr->xScrollUnit - 1)
-		/listPtr->xScrollUnit;
+		/ listPtr->xScrollUnit;
 	if (width < 1) {
 	    width = 1;
 	}
@@ -2439,13 +2446,13 @@ ListboxDeleteSubCmd(
 	 * Remove selection information.
 	 */
 
-	entry = Tcl_FindHashEntry(listPtr->selection, (char *) INT2PTR(i));
+	entry = Tcl_FindHashEntry(listPtr->selection, KEY(i));
 	if (entry != NULL) {
 	    listPtr->numSelected--;
 	    Tcl_DeleteHashEntry(entry);
 	}
 
-	entry = Tcl_FindHashEntry(listPtr->itemAttrTable, (char *) INT2PTR(i));
+	entry = Tcl_FindHashEntry(listPtr->itemAttrTable, KEY(i));
 	if (entry != NULL) {
 	    ckfree(Tcl_GetHashValue(entry));
 	    Tcl_DeleteHashEntry(entry);
@@ -2739,18 +2746,12 @@ GetListboxIndex(
 	start = stringRep + 1;
 	y = strtol(start, &end, 0);
 	if ((start == end) || (*end != ',')) {
-	    Tcl_AppendResult(interp, "bad listbox index \"", stringRep,
-		    "\": must be active, anchor, end, @x,y, or a number",
-		    NULL);
-	    return TCL_ERROR;
+	    goto badIndex;
 	}
 	start = end+1;
 	y = strtol(start, &end, 0);
 	if ((start == end) || (*end != '\0')) {
-	    Tcl_AppendResult(interp, "bad listbox index \"", stringRep,
-		    "\": must be active, anchor, end, @x,y, or a number",
-		    NULL);
-	    return TCL_ERROR;
+	    goto badIndex;
 	}
 	*indexPtr = NearestListboxElement(listPtr, y);
 	return TCL_OK;
@@ -2768,10 +2769,11 @@ GetListboxIndex(
      * Everything failed, nothing matched. Throw up an error message.
      */
 
-    Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp, "bad listbox index \"",
-	    Tcl_GetString(indexObj), "\": must be active, anchor, ",
-	    "end, @x,y, or a number", NULL);
+  badIndex:
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad listbox index \"%s\": must be active, anchor, end, @x,y,"
+	    " or a number", Tcl_GetString(indexObj)));
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "LISTBOX_INDEX", NULL);
     return TCL_ERROR;
 }
 
@@ -2903,7 +2905,7 @@ ListboxScanTo(
      */
 
     newTopIndex = listPtr->scanMarkYIndex
-	    - (10*(y - listPtr->scanMarkY))/listPtr->lineHeight;
+	    - (10*(y - listPtr->scanMarkY)) / listPtr->lineHeight;
     if (newTopIndex > maxIndex) {
 	newTopIndex = listPtr->scanMarkYIndex = maxIndex;
 	listPtr->scanMarkY = y;
@@ -2955,7 +2957,7 @@ NearestListboxElement(
 {
     int index;
 
-    index = (y - listPtr->inset)/listPtr->lineHeight;
+    index = (y - listPtr->inset) / listPtr->lineHeight;
     if (index >= (listPtr->fullLines + listPtr->partialLine)) {
 	index = listPtr->fullLines + listPtr->partialLine - 1;
     }
@@ -3026,7 +3028,7 @@ ListboxSelect(
      */
 
     for (i = first; i <= last; i++) {
-	entry = Tcl_FindHashEntry(listPtr->selection, (char *) INT2PTR(i));
+	entry = Tcl_FindHashEntry(listPtr->selection, KEY(i));
 	if (entry != NULL) {
 	    if (!select) {
 		Tcl_DeleteHashEntry(entry);
@@ -3037,8 +3039,8 @@ ListboxSelect(
 	    }
 	} else {
 	    if (select) {
-		entry = Tcl_CreateHashEntry(listPtr->selection,
-			(char *) INT2PTR(i), &isNew);
+		entry = Tcl_CreateHashEntry(listPtr->selection, KEY(i),
+			&isNew);
 		Tcl_SetHashValue(entry, NULL);
 		listPtr->numSelected++;
 		if (firstRedisplay < 0) {
@@ -3052,7 +3054,7 @@ ListboxSelect(
 	EventuallyRedrawRange(listPtr, first, last);
     }
     if ((oldCount == 0) && (listPtr->numSelected > 0)
-	    && (listPtr->exportSelection)) {
+	    && listPtr->exportSelection) {
 	Tk_OwnSelection(listPtr->tkwin, XA_PRIMARY,
 		ListboxLostSelection, listPtr);
     }
@@ -3109,7 +3111,7 @@ ListboxFetchSelection(
     needNewline = 0;
     Tcl_DStringInit(&selection);
     for (i = 0; i < listPtr->nElements; i++) {
-	entry = Tcl_FindHashEntry(listPtr->selection, (char *) INT2PTR(i));
+	entry = Tcl_FindHashEntry(listPtr->selection, KEY(i));
 	if (entry != NULL) {
 	    if (needNewline) {
 		Tcl_DStringAppend(&selection, "\n", 1);
@@ -3250,9 +3252,9 @@ ListboxUpdateVScrollbar(
 	first = 0.0;
 	last = 1.0;
     } else {
-	first = listPtr->topIndex / ((double) listPtr->nElements);
+	first = listPtr->topIndex / (double) listPtr->nElements;
 	last = (listPtr->topIndex + listPtr->fullLines)
-		/ ((double) listPtr->nElements);
+		/ (double) listPtr->nElements;
 	if (last > 1.0) {
 	    last = 1.0;
 	}
@@ -3309,15 +3311,15 @@ ListboxUpdateHScrollbar(
     if (listPtr->xScrollCmd == NULL) {
 	return;
     }
-    windowWidth = Tk_Width(listPtr->tkwin) - 2*(listPtr->inset
-	    + listPtr->selBorderWidth);
+
+    windowWidth = Tk_Width(listPtr->tkwin)
+	    - 2*(listPtr->inset + listPtr->selBorderWidth);
     if (listPtr->maxWidth == 0) {
 	first = 0;
 	last = 1.0;
     } else {
-	first = listPtr->xOffset/((double) listPtr->maxWidth);
-	last = (listPtr->xOffset + windowWidth)
-		/((double) listPtr->maxWidth);
+	first = listPtr->xOffset / (double) listPtr->maxWidth;
+	last = (listPtr->xOffset + windowWidth) / (double) listPtr->maxWidth;
 	if (last > 1.0) {
 	    last = 1.0;
 	}
@@ -3429,7 +3431,7 @@ ListboxListVarProc(
 	     * Clean up selection.
 	     */
 
-	    entry = Tcl_FindHashEntry(listPtr->selection, (char *) INT2PTR(i));
+	    entry = Tcl_FindHashEntry(listPtr->selection, KEY(i));
 	    if (entry != NULL) {
 		listPtr->numSelected--;
 		Tcl_DeleteHashEntry(entry);
@@ -3439,8 +3441,7 @@ ListboxListVarProc(
 	     * Clean up attributes.
 	     */
 
-	    entry = Tcl_FindHashEntry(listPtr->itemAttrTable,
-		    (char *) INT2PTR(i));
+	    entry = Tcl_FindHashEntry(listPtr->itemAttrTable, KEY(i));
 	    if (entry != NULL) {
 		ckfree(Tcl_GetHashValue(entry));
 		Tcl_DeleteHashEntry(entry);
@@ -3514,23 +3515,21 @@ MigrateHashEntries(
 
     if (offset > 0) {
 	for (i = last; i >= first; i--) {
-	    entry = Tcl_FindHashEntry(table, (char *) INT2PTR(i));
+	    entry = Tcl_FindHashEntry(table, KEY(i));
 	    if (entry != NULL) {
 		clientData = Tcl_GetHashValue(entry);
 		Tcl_DeleteHashEntry(entry);
-		entry = Tcl_CreateHashEntry(table,
-			(char *) INT2PTR(i + offset), &isNew);
+		entry = Tcl_CreateHashEntry(table, KEY(i + offset), &isNew);
 		Tcl_SetHashValue(entry, clientData);
 	    }
 	}
     } else {
 	for (i = first; i <= last; i++) {
-	    entry = Tcl_FindHashEntry(table, (char *) INT2PTR(i));
+	    entry = Tcl_FindHashEntry(table, KEY(i));
 	    if (entry != NULL) {
 		clientData = Tcl_GetHashValue(entry);
 		Tcl_DeleteHashEntry(entry);
-		entry = Tcl_CreateHashEntry(table,
-			(char *) INT2PTR(i + offset), &isNew);
+		entry = Tcl_CreateHashEntry(table, KEY(i + offset), &isNew);
 		Tcl_SetHashValue(entry, clientData);
 	    }
 	}
diff --git a/generic/tkMenu.c b/generic/tkMenu.c
index 49f49ad..12d6ebd 100644
--- a/generic/tkMenu.c
+++ b/generic/tkMenu.c
@@ -374,8 +374,8 @@ static void		TkMenuCleanup(ClientData unused);
 static const Tk_ClassProcs menuClass = {
     sizeof(Tk_ClassProcs),	/* size */
     MenuWorldChanged,		/* worldChangedProc */
-    NULL,					/* createProc */
-    NULL					/* modalProc */
+    NULL,			/* createProc */
+    NULL			/* modalProc */
 };
 
 /*
@@ -889,7 +889,7 @@ MenuWidgetObjCmd(
 	    goto error;
 	}
 	if (index < 0) {
-	    Tcl_SetResult(interp, "none", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj("none", -1));
 	} else {
 	    Tcl_SetObjResult(interp, Tcl_NewIntObj(index));
 	}
@@ -966,6 +966,7 @@ MenuWidgetObjCmd(
     }
     case MENU_TYPE: {
 	int index;
+	const char *typeStr;
 
 	if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 2, objv, "index");
@@ -978,11 +979,11 @@ MenuWidgetObjCmd(
 	    goto done;
 	}
 	if (menuPtr->entries[index]->type == TEAROFF_ENTRY) {
-	    Tcl_SetResult(interp, "tearoff", TCL_STATIC);
+	    typeStr = "tearoff";
 	} else {
-	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
-		    menuEntryTypeStrings[menuPtr->entries[index]->type], -1));
+	    typeStr = menuEntryTypeStrings[menuPtr->entries[index]->type];
 	}
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(typeStr, -1));
 	break;
     }
     case MENU_UNPOST:
@@ -2206,7 +2207,9 @@ TkGetMenuIndex(
 	}
     }
 
-    Tcl_AppendResult(interp, "bad menu entry index \"", string, "\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad menu entry index \"%s\"", string));
+    Tcl_SetErrorCode(interp, "TK", "MENU", "INDEX", NULL);
     return TCL_ERROR;
 
   success:
@@ -2390,9 +2393,9 @@ MenuAddOrInsert(
 	index = menuPtr->numEntries;
     }
     if (index < 0) {
-	const char *indexString = Tcl_GetString(indexPtr);
-
-	Tcl_AppendResult(interp, "bad index \"", indexString, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad index \"%s\"", Tcl_GetString(indexPtr)));
+	Tcl_SetErrorCode(interp, "TK", "MENU", "INDEX", NULL);
 	return TCL_ERROR;
     }
     if (menuPtr->tearoff && (index == 0)) {
@@ -3265,6 +3268,7 @@ TkSetWindowMenuBar(
 		    && (cloneMenuRefPtr->menuPtr != NULL)) {
 		Tcl_Obj *cursorPtr = Tcl_NewStringObj("-cursor", -1);
 		Tcl_Obj *nullPtr = Tcl_NewObj();
+
 		cloneMenuRefPtr->menuPtr->parentTopLevelPtr = tkwin;
 		menuBarPtr = cloneMenuRefPtr->menuPtr;
 		newObjv[0] = cursorPtr;
@@ -3468,6 +3472,7 @@ TkFindMenuReferencesObj(
     Tcl_Obj *objPtr)		/* The path of the menu widget. */
 {
     const char *pathName = Tcl_GetString(objPtr);
+
     return TkFindMenuReferences(interp, pathName);
 }
 
diff --git a/generic/tkMenubutton.c b/generic/tkMenubutton.c
index 31dbfbb..545401c 100644
--- a/generic/tkMenubutton.c
+++ b/generic/tkMenubutton.c
@@ -23,8 +23,8 @@
 static const Tk_ClassProcs menubuttonClass = {
     sizeof(Tk_ClassProcs),	/* size */
     TkMenuButtonWorldChanged,	/* worldChangedProc */
-    NULL,					/* createProc */
-    NULL					/* modalProc */
+    NULL,			/* createProc */
+    NULL			/* modalProc */
 };
 
 /*
diff --git a/generic/tkMessage.c b/generic/tkMessage.c
index 0787efc..4779e00 100644
--- a/generic/tkMessage.c
+++ b/generic/tkMessage.c
@@ -191,8 +191,8 @@ static void		DisplayMessage(ClientData clientData);
 static const Tk_ClassProcs messageClass = {
     sizeof(Tk_ClassProcs),	/* size */
     MessageWorldChanged,	/* worldChangedProc */
-    NULL,					/* createProc */
-    NULL					/* modalProc */
+    NULL,			/* createProc */
+    NULL			/* modalProc */
 };
 
 /*
@@ -277,7 +277,7 @@ Tk_MessageObjCmd(
 	return TCL_ERROR;
     }
 
-    Tcl_SetResult(interp, Tk_PathName(msgPtr->tkwin), TCL_STATIC);
+    Tcl_SetObjResult(interp, TkNewWindowObj(msgPtr->tkwin));
     return TCL_OK;
 }
 
diff --git a/generic/tkObj.c b/generic/tkObj.c
index 8877d42..ed947d3 100644
--- a/generic/tkObj.c
+++ b/generic/tkObj.c
@@ -506,6 +506,7 @@ SetPixelFromAny(
     if (interp != NULL) {
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"bad screen distance \"%.50s\"", string));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "PIXELS", NULL);
     }
     return TCL_ERROR;
 }
@@ -734,8 +735,9 @@ SetMMFromAny(
 	     */
 
 	error:
-	    Tcl_AppendResult(interp, "bad screen distance \"", string,
-		    "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad screen distance \"%s\"", string));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "DISTANCE", NULL);
 	    return TCL_ERROR;
 	}
 	while ((*rest != '\0') && isspace(UCHAR(*rest))) {
@@ -1032,10 +1034,10 @@ TkParsePadAmount(
 
     if (specObj->typePtr == &pixelObjType) {
 	if (Tk_GetPixelsFromObj(interp, tkwin, specObj, &firstInt) != TCL_OK){
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "bad pad value \"",
-		    Tcl_GetString(specObj),
-		    "\": must be positive screen distance", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad pad value \"%s\": must be positive screen distance",
+		    Tcl_GetString(specObj)));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "PADDING", "DIST", NULL);
 	    return TCL_ERROR;
 	}
 	secondInt = firstInt;
@@ -1051,8 +1053,9 @@ TkParsePadAmount(
 	return TCL_ERROR;
     }
     if (objc != 1 && objc != 2) {
-	Tcl_AppendResult(interp,
-		"wrong number of parts to pad specification", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"wrong number of parts to pad specification", -1));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "PADDING", "PARTS", NULL);
 	return TCL_ERROR;
     }
 
@@ -1062,9 +1065,10 @@ TkParsePadAmount(
 
     if (Tk_GetPixelsFromObj(interp, tkwin, objv[0], &firstInt) != TCL_OK ||
 	    (firstInt < 0)) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "bad pad value \"", Tcl_GetString(objv[0]),
-		"\": must be positive screen distance", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad pad value \"%s\": must be positive screen distance",
+		Tcl_GetString(objv[0])));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "PADDING", "DIST", NULL);
 	return TCL_ERROR;
     }
 
@@ -1077,10 +1081,10 @@ TkParsePadAmount(
 	secondInt = firstInt;
     } else if (Tk_GetPixelsFromObj(interp, tkwin, objv[1],
 	    &secondInt) != TCL_OK || (secondInt < 0)) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "bad 2nd pad value \"",
-		Tcl_GetString(objv[1]),
-		"\": must be positive screen distance", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad 2nd pad value \"%s\": must be positive screen distance",
+		Tcl_GetString(objv[1])));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "PADDING", "DIST", NULL);
 	return TCL_ERROR;
     }
 
diff --git a/generic/tkOldConfig.c b/generic/tkOldConfig.c
index 1ab6ab6..5496076 100644
--- a/generic/tkOldConfig.c
+++ b/generic/tkOldConfig.c
@@ -95,7 +95,8 @@ Tk_ConfigureWidget(
 	 * we're on our way out of the application
 	 */
 
-	Tcl_AppendResult(interp, "NULL main window", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj("NULL main window", -1));
+	Tcl_SetErrorCode(interp, "TK", "NO_MAIN_WINDOW", NULL);
 	return TCL_ERROR;
     }
 
@@ -135,7 +136,9 @@ Tk_ConfigureWidget(
 	 */
 
 	if (argc < 2) {
-	    Tcl_AppendResult(interp, "value for \"", arg, "\" missing", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "value for \"%s\" missing", arg));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE_MISSING", NULL);
 	    return TCL_ERROR;
 	}
 	if (flags & TK_CONFIG_OBJS) {
@@ -144,11 +147,8 @@ Tk_ConfigureWidget(
 	    arg = argv[1];
 	}
 	if (DoConfig(interp, tkwin, specPtr, arg, 0, widgRec) != TCL_OK) {
-	    char msg[100];
-
-	    sprintf(msg, "\n    (processing \"%.40s\" option)",
-		    specPtr->argvName);
-	    Tcl_AddErrorInfo(interp, msg);
+	    Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
+		    "\n    (processing \"%.40s\" option)",specPtr->argvName));
 	    return TCL_ERROR;
 	}
 	if (!(flags & TK_CONFIG_ARGV_ONLY)) {
@@ -181,12 +181,10 @@ Tk_ConfigureWidget(
 	    if (value != NULL) {
 		if (DoConfig(interp, tkwin, specPtr, value, 1, widgRec) !=
 			TCL_OK) {
-		    char msg[200];
-
-		    sprintf(msg, "\n    (%s \"%.50s\" in widget \"%.50s\")",
-			    "database entry for",
-			    specPtr->dbName, Tk_PathName(tkwin));
-		    Tcl_AddErrorInfo(interp, msg);
+		    Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
+			    "\n    (%s \"%.50s\" in widget \"%.50s\")",
+			    "database entry for", specPtr->dbName,
+			    Tk_PathName(tkwin)));
 		    return TCL_ERROR;
 		}
 	    } else {
@@ -199,13 +197,10 @@ Tk_ConfigureWidget(
 			& TK_CONFIG_DONT_SET_DEFAULT)) {
 		    if (DoConfig(interp, tkwin, specPtr, value, 1, widgRec) !=
 			    TCL_OK) {
-			char msg[200];
-
-			sprintf(msg,
+			Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
 				"\n    (%s \"%.50s\" in widget \"%.50s\")",
-				"default value for",
-				specPtr->dbName, Tk_PathName(tkwin));
-			Tcl_AddErrorInfo(interp, msg);
+				"default value for", specPtr->dbName,
+				Tk_PathName(tkwin)));
 			return TCL_ERROR;
 		    }
 		}
@@ -272,15 +267,18 @@ FindConfigSpec(
 	    goto gotMatch;
 	}
 	if (matchPtr != NULL) {
-	    Tcl_AppendResult(interp, "ambiguous option \"", argvName,
-		    "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "ambiguous option \"%s\"", argvName));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "OPTION", argvName,NULL);
 	    return NULL;
 	}
 	matchPtr = specPtr;
     }
 
     if (matchPtr == NULL) {
-	Tcl_AppendResult(interp, "unknown option \"", argvName, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"unknown option \"%s\"", argvName));
+	Tcl_SetErrorCode(interp, "TK", "LOOKUP", "OPTION", argvName, NULL);
 	return NULL;
     }
 
@@ -294,8 +292,11 @@ FindConfigSpec(
     if (specPtr->type == TK_CONFIG_SYNONYM) {
 	for (specPtr = specs; ; specPtr++) {
 	    if (specPtr->type == TK_CONFIG_END) {
-		Tcl_AppendResult(interp, "couldn't find synonym for option \"",
-			argvName, "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"couldn't find synonym for option \"%s\"",
+			argvName));
+		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "OPTION", argvName,
+			NULL);
 		return NULL;
 	    }
 	    if ((specPtr->dbName == matchPtr->dbName)
@@ -546,14 +547,12 @@ DoConfig(
 		return TCL_ERROR;
 	    }
 	    break;
-	default: {
-	    char buf[64 + TCL_INTEGER_SPACE];
-
-	    sprintf(buf, "bad config table: unknown type %d", specPtr->type);
-	    Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	default:
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad config table: unknown type %d", specPtr->type));
+	    Tcl_SetErrorCode(interp, "TK", "BAD_CONFIG", NULL);
 	    return TCL_ERROR;
 	}
-	}
 	specPtr++;
     } while ((specPtr->argvName == NULL) && (specPtr->type != TK_CONFIG_END));
     return TCL_OK;
@@ -626,12 +625,13 @@ Tk_ConfigureInfo(
 
     Tcl_ResetResult(interp);
     if (argvName != NULL) {
-	specPtr = FindConfigSpec(interp, staticSpecs, argvName, needFlags,hateFlags);
+	specPtr = FindConfigSpec(interp, staticSpecs, argvName, needFlags,
+		hateFlags);
 	if (specPtr == NULL) {
 	    return TCL_ERROR;
 	}
 	list = FormatConfigInfo(interp, tkwin, specPtr, widgRec);
-	Tcl_SetResult(interp, list, TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(list, -1));
 	ckfree(list);
 	return TCL_OK;
     }
@@ -936,7 +936,7 @@ Tk_ConfigureValue(
     }
     result = FormatConfigValue(interp, tkwin, specPtr, widgRec, buffer,
 	    &freeProc);
-    Tcl_SetResult(interp, (char *) result, TCL_VOLATILE);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(result, -1));
     if (freeProc != NULL) {
 	if ((freeProc == TCL_DYNAMIC) || (freeProc == (Tcl_FreeProc *) free)) {
 	    ckfree(result);
diff --git a/generic/tkOption.c b/generic/tkOption.c
index d5c423f..ec9e465 100644
--- a/generic/tkOption.c
+++ b/generic/tkOption.c
@@ -541,7 +541,7 @@ Tk_GetOption(
 
 	winClassId = Tk_GetUid(masqClass);
 	ckfree(masqClass);
-	winNameId = ((TkWindow *)tkwin)->nameUid;
+	winNameId = ((TkWindow *) tkwin)->nameUid;
 
 	levelPtr = &tsdPtr->levels[tsdPtr->curLevel];
 
@@ -619,11 +619,9 @@ Tk_OptionObjCmd(
     int index, result;
     ThreadSpecificData *tsdPtr =
 	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
-
     static const char *const optionCmds[] = {
 	"add", "clear", "get", "readfile", NULL
     };
-
     enum optionVals {
 	OPTION_ADD, OPTION_CLEAR, OPTION_GET, OPTION_READFILE
     };
@@ -663,13 +661,12 @@ Tk_OptionObjCmd(
     }
 
     case OPTION_CLEAR: {
-	TkMainInfo *mainPtr;
+	TkMainInfo *mainPtr = ((TkWindow *) tkwin)->mainPtr;
 
 	if (objc != 2) {
 	    Tcl_WrongNumArgs(interp, 2, objv, "");
 	    return TCL_ERROR;
 	}
-	mainPtr = ((TkWindow *) tkwin)->mainPtr;
 	if (mainPtr->optionRootPtr != NULL) {
 	    ClearOptionTree(mainPtr->optionRootPtr);
 	    mainPtr->optionRootPtr = NULL;
@@ -693,7 +690,7 @@ Tk_OptionObjCmd(
 	value = Tk_GetOption(window, Tcl_GetString(objv[3]),
 		Tcl_GetString(objv[4]));
 	if (value != NULL) {
-	    Tcl_SetResult(interp, (char *) value, TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(value, -1));
 	}
 	break;
     }
@@ -880,9 +877,11 @@ ParsePriority(
 	priority = strtoul(string, &end, 0);
 	if ((end == string) || (*end != 0) || (priority < 0)
 		|| (priority > 100)) {
-	    Tcl_AppendResult(interp, "bad priority level \"", string,
-		    "\": must be widgetDefault, startupFile, userDefault, ",
-		    "interactive, or a number between 0 and 100", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad priority level \"%s\": must be "
+		    "widgetDefault, startupFile, userDefault, "
+		    "interactive, or a number between 0 and 100", string));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "PRIORITY", NULL);
 	    return -1;
 	}
     }
@@ -964,10 +963,9 @@ AddFromString(
 	dst = name = src;
 	while (*src != ':') {
 	    if ((*src == '\0') || (*src == '\n')) {
-		char buf[32 + TCL_INTEGER_SPACE];
-
-		sprintf(buf, "missing colon on line %d", lineNum);
-		Tcl_SetResult(interp, buf, TCL_VOLATILE);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"missing colon on line %d", lineNum));
+		Tcl_SetErrorCode(interp, "TK", "OPTIONDB", "COLON", NULL);
 		return TCL_ERROR;
 	    }
 	    if ((src[0] == '\\') && (src[1] == '\n')) {
@@ -999,10 +997,9 @@ AddFromString(
 	    src++;
 	}
 	if (*src == '\0') {
-	    char buf[32 + TCL_INTEGER_SPACE];
-
-	    sprintf(buf, "missing value on line %d", lineNum);
-	    Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "missing value on line %d", lineNum));
+	    Tcl_SetErrorCode(interp, "TK", "OPTIONDB", "VALUE", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1014,10 +1011,9 @@ AddFromString(
 	dst = value = src;
 	while (*src != '\n') {
 	    if (*src == '\0') {
-		char buf[32 + TCL_INTEGER_SPACE];
-
-		sprintf(buf, "missing newline on line %d", lineNum);
-		Tcl_SetResult(interp, buf, TCL_VOLATILE);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"missing newline on line %d", lineNum));
+		Tcl_SetErrorCode(interp, "TK", "OPTIONDB", "NEWLINE", NULL);
 		return TCL_ERROR;
 	    }
 	    if ((src[0] == '\\') && (src[1] == '\n')) {
@@ -1066,7 +1062,7 @@ ReadOptionFile(
     Tcl_Interp *interp,		/* Interpreter to use for reporting results. */
     Tk_Window tkwin,		/* Token for window: options are entered for
 				 * this window's main window. */
-    const char *fileName,		/* Name of file containing options. */
+    const char *fileName,	/* Name of file containing options. */
     int priority)		/* Priority level to use for options in this
 				 * file, such as TK_USER_DEFAULT_PRIO or
 				 * TK_INTERACTIVE_PRIO. Must be between 0 and
@@ -1083,8 +1079,9 @@ ReadOptionFile(
      */
 
     if (Tcl_IsSafe(interp)) {
-	Tcl_AppendResult(interp, "can't read options from a file in a",
-		" safe interpreter", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"can't read options from a file in a safe interpreter", -1));
+	Tcl_SetErrorCode(interp, "TK", "SAFE", "OPTION_FILE", NULL);
 	return TCL_ERROR;
     }
 
@@ -1095,9 +1092,8 @@ ReadOptionFile(
     chan = Tcl_OpenFileChannel(interp, realName, "r", 0);
     Tcl_DStringFree(&newName);
     if (chan == NULL) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "couldn't open \"", fileName,
-		"\": ", Tcl_PosixError(interp), NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf("couldn't open \"%s\": %s",
+		fileName, Tcl_PosixError(interp)));
 	return TCL_ERROR;
     }
 
@@ -1110,8 +1106,9 @@ ReadOptionFile(
     Tcl_Seek(chan, (Tcl_WideInt) 0, SEEK_SET);
 
     if (bufferSize < 0) {
-	Tcl_AppendResult(interp, "error seeking to end of file \"",
-		fileName, "\":", Tcl_PosixError(interp), NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"error seeking to end of file \"%s\": %s",
+		fileName, Tcl_PosixError(interp)));
 	Tcl_Close(NULL, chan);
 	return TCL_ERROR;
     }
@@ -1119,8 +1116,9 @@ ReadOptionFile(
     buffer = ckalloc(bufferSize + 1);
     bufferSize = Tcl_Read(chan, buffer, bufferSize);
     if (bufferSize < 0) {
-	Tcl_AppendResult(interp, "error reading file \"", fileName, "\":",
-		Tcl_PosixError(interp), NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"error reading file \"%s\": %s",
+		fileName, Tcl_PosixError(interp)));
 	Tcl_Close(NULL, chan);
 	return TCL_ERROR;
     }
@@ -1309,6 +1307,7 @@ SetupStacks(
     if (tsdPtr->curLevel >= tsdPtr->numLevels) {
 	StackLevel *newLevels =
 		ckalloc(tsdPtr->numLevels * 2 * sizeof(StackLevel));
+
 	memcpy(newLevels, tsdPtr->levels,
 		tsdPtr->numLevels * sizeof(StackLevel));
 	ckfree(tsdPtr->levels);
diff --git a/generic/tkPack.c b/generic/tkPack.c
index b32cc23..134b61f 100644
--- a/generic/tkPack.c
+++ b/generic/tkPack.c
@@ -133,11 +133,11 @@ static int		YExpansion(Packer *slavePtr, int cavityHeight);
 /*
  *------------------------------------------------------------------------
  *
- * TkPrintPadAmount --
+ * TkAppendPadAmount --
  *
  *	This function generates a text value that describes one of the -padx,
  *	-pady, -ipadx, or -ipady configuration options. The text value
- *	generated is appended to the interpreter result.
+ *	generated is appended to the given Tcl_Obj.
  *
  * Results:
  *	None.
@@ -149,21 +149,25 @@ static int		YExpansion(Packer *slavePtr, int cavityHeight);
  */
 
 void
-TkPrintPadAmount(
-    Tcl_Interp *interp,		/* The interpreter into which the result is
+TkAppendPadAmount(
+    Tcl_Obj *bufferObj,		/* The interpreter into which the result is
 				 * written. */
-    const char *switchName,		/* One of "padx", "pady", "ipadx" or "ipady" */
+    const char *switchName,	/* One of "padx", "pady", "ipadx" or
+				 * "ipady" */
     int halfSpace,		/* The left or top padding amount */
     int allSpace)		/* The total amount of padding */
 {
-    char buffer[60 + 2*TCL_INTEGER_SPACE];
+    Tcl_Obj *padding[2];
+
     if (halfSpace*2 == allSpace) {
-	sprintf(buffer, " -%.10s %d", switchName, halfSpace);
+	Tcl_DictObjPut(NULL, bufferObj, Tcl_NewStringObj(switchName, -1),
+		Tcl_NewIntObj(halfSpace));
     } else {
-	sprintf(buffer, " -%.10s {%d %d}", switchName, halfSpace,
-		allSpace - halfSpace);
+	padding[0] = Tcl_NewIntObj(halfSpace);
+	padding[1] = Tcl_NewIntObj(allSpace - halfSpace);
+	Tcl_DictObjPut(NULL, bufferObj, Tcl_NewStringObj(switchName, -1),
+		Tcl_NewListObj(2, padding));
     }
-    Tcl_AppendResult(interp, buffer, NULL);
 }
 
 /*
@@ -238,8 +242,9 @@ Tk_PackObjCmd(
 	}
 	prevPtr = GetPacker(tkwin2);
 	if (prevPtr->masterPtr == NULL) {
-	    Tcl_AppendResult(interp, "window \"", argv2,
-		    "\" isn't packed", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "window \"%s\" isn't packed", argv2));
+	    Tcl_SetErrorCode(interp, "TK", "PACK", "NOT_PACKED", NULL);
 	    return TCL_ERROR;
 	}
 	return PackAfter(interp, prevPtr, prevPtr->masterPtr, objc-3, objv+3);
@@ -271,8 +276,9 @@ Tk_PackObjCmd(
 	}
 	packPtr = GetPacker(tkwin2);
 	if (packPtr->masterPtr == NULL) {
-	    Tcl_AppendResult(interp, "window \"", argv2,
-		    "\" isn't packed", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "window \"%s\" isn't packed", argv2));
+	    Tcl_SetErrorCode(interp, "TK", "PACK", "NOT_PACKED", NULL);
 	    return TCL_ERROR;
 	}
 	masterPtr = packPtr->masterPtr;
@@ -293,8 +299,9 @@ Tk_PackObjCmd(
     }
     case PACK_CONFIGURE:
 	if (argv2[0] != '.') {
-	    Tcl_AppendResult(interp, "bad argument \"", argv2,
-		    "\": must be name of window", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad argument \"%s\": must be name of window", argv2));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "WINDOW_PATH", NULL);
 	    return TCL_ERROR;
 	}
 	return ConfigureSlaves(interp, tkwin, objc-2, objv+2);
@@ -323,6 +330,7 @@ Tk_PackObjCmd(
     case PACK_INFO: {
 	register Packer *slavePtr;
 	Tk_Window slave;
+	Tcl_Obj *infoObj;
 
 	if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 2, objv, "window");
@@ -333,35 +341,44 @@ Tk_PackObjCmd(
 	}
 	slavePtr = GetPacker(slave);
 	if (slavePtr->masterPtr == NULL) {
-	    Tcl_AppendResult(interp, "window \"", argv2,
-		    "\" isn't packed", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "window \"%s\" isn't packed", argv2));
+	    Tcl_SetErrorCode(interp, "TK", "PACK", "NOT_PACKED", NULL);
 	    return TCL_ERROR;
 	}
-	Tcl_AppendElement(interp, "-in");
-	Tcl_AppendElement(interp, Tk_PathName(slavePtr->masterPtr->tkwin));
-	Tcl_AppendElement(interp, "-anchor");
-	Tcl_AppendElement(interp, Tk_NameOfAnchor(slavePtr->anchor));
-	Tcl_AppendResult(interp, " -expand ",
-		(slavePtr->flags & EXPAND) ? "1" : "0", " -fill ", NULL);
+
+	infoObj = Tcl_NewObj();
+	Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-in", -1),
+		TkNewWindowObj(slavePtr->masterPtr->tkwin));
+	Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-anchor", -1),
+		Tcl_NewStringObj(Tk_NameOfAnchor(slavePtr->anchor), -1));
+	Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-expand", -1),
+		Tcl_NewBooleanObj(slavePtr->flags & EXPAND));
 	switch (slavePtr->flags & (FILLX|FILLY)) {
 	case 0:
-	    Tcl_AppendResult(interp, "none", NULL);
+	    Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-fill", -1),
+		    Tcl_NewStringObj("none", -1));
 	    break;
 	case FILLX:
-	    Tcl_AppendResult(interp, "x", NULL);
+	    Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-fill", -1),
+		    Tcl_NewStringObj("x", -1));
 	    break;
 	case FILLY:
-	    Tcl_AppendResult(interp, "y", NULL);
+	    Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-fill", -1),
+		    Tcl_NewStringObj("y", -1));
 	    break;
 	case FILLX|FILLY:
-	    Tcl_AppendResult(interp, "both", NULL);
+	    Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-fill", -1),
+		    Tcl_NewStringObj("both", -1));
 	    break;
 	}
-	TkPrintPadAmount(interp, "ipadx", slavePtr->iPadX/2, slavePtr->iPadX);
-	TkPrintPadAmount(interp, "ipady", slavePtr->iPadY/2, slavePtr->iPadY);
-	TkPrintPadAmount(interp, "padx", slavePtr->padLeft, slavePtr->padX);
-	TkPrintPadAmount(interp, "pady", slavePtr->padTop, slavePtr->padY);
-	Tcl_AppendResult(interp, " -side ", sideNames[slavePtr->side], NULL);
+	TkAppendPadAmount(infoObj, "-ipadx", slavePtr->iPadX/2, slavePtr->iPadX);
+	TkAppendPadAmount(infoObj, "-ipady", slavePtr->iPadY/2, slavePtr->iPadY);
+	TkAppendPadAmount(infoObj, "-padx", slavePtr->padLeft,slavePtr->padX);
+	TkAppendPadAmount(infoObj, "-pady", slavePtr->padTop, slavePtr->padY);
+	Tcl_DictObjPut(NULL, infoObj, Tcl_NewStringObj("-side", -1),
+		Tcl_NewStringObj(sideNames[slavePtr->side], -1));
+	Tcl_SetObjResult(interp, infoObj);
 	break;
     }
     case PACK_PROPAGATE: {
@@ -1096,9 +1113,10 @@ PackAfter(
 
     for ( ; objc > 0; objc -= 2, objv += 2, prevPtr = packPtr) {
 	if (objc < 2) {
-	    Tcl_AppendResult(interp, "wrong # args: window \"",
-		    Tcl_GetString(objv[0]), "\" should be followed by options",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # args: window \"%s\" should be followed by options",
+		    Tcl_GetString(objv[0])));
+	    Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1120,8 +1138,10 @@ PackAfter(
 	    }
 	    if (((Tk_FakeWin *) (ancestor))->flags & TK_TOP_HIERARCHY) {
 	    badWindow:
-		Tcl_AppendResult(interp, "can't pack ", Tcl_GetString(objv[0]),
-			" inside ", Tk_PathName(masterPtr->tkwin), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"can't pack %s inside %s", Tcl_GetString(objv[0]),
+			Tk_PathName(masterPtr->tkwin)));
+		Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "HIERARCHY", NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -1179,8 +1199,10 @@ PackAfter(
 	    } else if ((c == 'p') && (strcmp(curOpt, "padx")) == 0) {
 		if (optionCount < (index+2)) {
 		missingPad:
-		    Tcl_AppendResult(interp, "wrong # args: \"", curOpt,
-			    "\" option must be followed by screen distance",
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "wrong # args: \"%s\" option must be"
+			    " followed by screen distance", curOpt));
+		    Tcl_SetErrorCode(interp, "TK", "OLDPACK", "BAD_PARAMETER",
 			    NULL);
 		    return TCL_ERROR;
 		}
@@ -1207,8 +1229,11 @@ PackAfter(
 	    } else if ((c == 'f') && (length > 1)
 		    && (strncmp(curOpt, "frame", (size_t) length) == 0)) {
 		if (optionCount < (index+2)) {
-		    Tcl_AppendResult(interp, "wrong # args: \"frame\" ",
-			    "option must be followed by anchor point", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "wrong # args: \"frame\""
+			    " option must be followed by anchor point", -1));
+		    Tcl_SetErrorCode(interp, "TK", "OLDPACK", "BAD_PARAMETER",
+			    NULL);
 		    return TCL_ERROR;
 		}
 		if (Tk_GetAnchorFromObj(interp, options[index+1],
@@ -1217,15 +1242,17 @@ PackAfter(
 		}
 		index++;
 	    } else {
-		Tcl_AppendResult(interp, "bad option \"", curOpt,
-			"\": should be top, bottom, left, right, expand, ",
-			"fill, fillx, filly, padx, pady, or frame", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"bad option \"%s\": should be top, bottom, left,"
+			" right, expand, fill, fillx, filly, padx, pady, or"
+			" frame", curOpt));
+		Tcl_SetErrorCode(interp, "TK", "OLDPACK", "BAD_PARAMETER",
+			NULL);
 		return TCL_ERROR;
 	    }
 	}
 
 	if (packPtr != prevPtr) {
-
 	    /*
 	     * Unpack this window if it's currently packed.
 	     */
@@ -1534,8 +1561,10 @@ ConfigureSlaves(
 	    return TCL_ERROR;
 	}
 	if (Tk_TopWinHierarchy(slave)) {
-	    Tcl_AppendResult(interp, "can't pack \"", Tcl_GetString(objv[j]),
-		    "\": it's a top-level window", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't pack \"%s\": it's a top-level window",
+		    Tcl_GetString(objv[j])));
+	    Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "TOPLEVEL", NULL);
 	    return TCL_ERROR;
 	}
 	slavePtr = GetPacker(slave);
@@ -1558,9 +1587,10 @@ ConfigureSlaves(
 
 	for (i = numWindows; i < objc; i+=2) {
 	    if ((i+2) > objc) {
-		Tcl_AppendResult(interp, "extra option \"",
-			Tcl_GetString(objv[i]),
-			"\" (option with no value?)", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"extra option \"%s\" (option with no value?)",
+			Tcl_GetString(objv[i])));
+		Tcl_SetErrorCode(interp, "TK", "PACK", "BAD_PARAMETER", NULL);
 		return TCL_ERROR;
 	    }
 	    if (Tcl_GetIndexFromObj(interp, objv[i], optionStrings, "option",
@@ -1578,8 +1608,10 @@ ConfigureSlaves(
 		    prevPtr = GetPacker(other);
 		    if (prevPtr->masterPtr == NULL) {
 		    notPacked:
-			Tcl_AppendResult(interp, "window \"",
-				Tcl_GetString(objv[i+1]), "\" isn't packed",
+			Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+				"window \"%s\" isn't packed",
+				Tcl_GetString(objv[i+1])));
+			Tcl_SetErrorCode(interp, "TK", "PACK", "NOT_PACKED",
 				NULL);
 			return TCL_ERROR;
 		    }
@@ -1635,8 +1667,10 @@ ConfigureSlaves(
 		} else if (strcmp(string, "both") == 0) {
 		    slavePtr->flags |= FILLX|FILLY;
 		} else {
-		    Tcl_AppendResult(interp, "bad fill style \"", string,
-			    "\": must be none, x, y, or both", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad fill style \"%s\": must be "
+			    "none, x, y, or both", string));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "FILL", NULL);
 		    return TCL_ERROR;
 		}
 		break;
@@ -1658,24 +1692,22 @@ ConfigureSlaves(
 		break;
 	    case CONF_IPADX:
 		if ((Tk_GetPixelsFromObj(interp, slave, objv[i+1], &tmp)
-			!= TCL_OK)
-			|| (tmp < 0)) {
-		    Tcl_ResetResult(interp);
-		    Tcl_AppendResult(interp, "bad ipadx value \"",
-			    Tcl_GetString(objv[i+1]),
-			    "\": must be positive screen distance", NULL);
+			!= TCL_OK) || (tmp < 0)) {
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad ipadx value \"%s\": must be positive screen"
+			    " distance", Tcl_GetString(objv[i+1])));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "INT_PAD", NULL);
 		    return TCL_ERROR;
 		}
 		slavePtr->iPadX = tmp * 2;
 		break;
 	    case CONF_IPADY:
 		if ((Tk_GetPixelsFromObj(interp, slave, objv[i+1], &tmp)
-			!= TCL_OK)
-			|| (tmp < 0)) {
-		    Tcl_ResetResult(interp);
-		    Tcl_AppendResult(interp, "bad ipady value \"",
-			    Tcl_GetString(objv[i+1]),
-			    "\": must be positive screen distance", NULL);
+			!= TCL_OK) || (tmp < 0)) {
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "bad ipady value \"%s\": must be positive screen"
+			    " distance", Tcl_GetString(objv[i+1])));
+		    Tcl_SetErrorCode(interp, "TK", "VALUE", "INT_PAD", NULL);
 		    return TCL_ERROR;
 		}
 		slavePtr->iPadY = tmp * 2;
@@ -1752,14 +1784,17 @@ ConfigureSlaves(
 		break;
 	    }
 	    if (Tk_TopWinHierarchy(ancestor)) {
-		Tcl_AppendResult(interp, "can't pack ", Tcl_GetString(objv[j]),
-			" inside ", Tk_PathName(masterPtr->tkwin), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"can't pack %s inside %s", Tcl_GetString(objv[j]),
+			Tk_PathName(masterPtr->tkwin)));
+		Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "HIERARCHY", NULL);
 		return TCL_ERROR;
 	    }
 	}
 	if (slave == masterPtr->tkwin) {
-	    Tcl_AppendResult(interp, "can't pack ", Tcl_GetString(objv[j]),
-		    " inside itself", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't pack %s inside itself", Tcl_GetString(objv[j])));
+	    Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "SELF", NULL);
 	    return TCL_ERROR;
 	}
 
diff --git a/generic/tkPanedWindow.c b/generic/tkPanedWindow.c
index 23ecf5d..4a4af53 100644
--- a/generic/tkPanedWindow.c
+++ b/generic/tkPanedWindow.c
@@ -658,10 +658,13 @@ PanedWindowWidgetObjCmd(
 			objv[3], tkwin);
 	    }
 	}
-	if (i == pwPtr->numSlaves) {
-	    Tcl_SetResult(interp, "not managed by this window", TCL_STATIC);
-	}
 	if (resultObj == NULL) {
+	    if (i == pwPtr->numSlaves) {
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"not managed by this window", -1));
+		Tcl_SetErrorCode(interp, "TK", "PANEDWINDOW", "UNMANAGED",
+			NULL);
+	    }
 	    result = TCL_ERROR;
 	} else {
 	    Tcl_SetObjResult(interp, resultObj);
@@ -700,15 +703,11 @@ PanedWindowWidgetObjCmd(
 
     case PW_PANES:
 	resultObj = Tcl_NewObj();
-
-	Tcl_IncrRefCount(resultObj);
-
 	for (i = 0; i < pwPtr->numSlaves; i++) {
-	    Tcl_ListObjAppendElement(interp, resultObj,
-		    Tcl_NewStringObj(Tk_PathName(pwPtr->slaves[i]->tkwin),-1));
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    TkNewWindowObj(pwPtr->slaves[i]->tkwin));
 	}
 	Tcl_SetObjResult(interp, resultObj);
-	Tcl_DecrRefCount(resultObj);
 	break;
 
     case PW_PROXY:
@@ -778,18 +777,19 @@ ConfigureSlaves(
 		 * A panedwindow cannot manage itself.
 		 */
 
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "can't add ", arg, " to itself",
-			NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"can't add %s to itself", arg));
+		Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "SELF", NULL);
 		return TCL_ERROR;
 	    } else if (Tk_IsTopLevel(tkwin)) {
 		/*
 		 * A panedwindow cannot manage a toplevel.
 		 */
 
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "can't add toplevel ", arg, " to ",
-			Tk_PathName(pwPtr->tkwin), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"can't add toplevel %s to %s", arg,
+			Tk_PathName(pwPtr->tkwin)));
+		Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "TOPLEVEL", NULL);
 		return TCL_ERROR;
 	    } else {
 		/*
@@ -803,9 +803,11 @@ ConfigureSlaves(
 			break;
 		    }
 		    if (Tk_IsTopLevel(ancestor)) {
-			Tcl_ResetResult(interp);
-			Tcl_AppendResult(interp, "can't add ", arg, " to ",
-				Tk_PathName(pwPtr->tkwin), NULL);
+			Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+				"can't add %s to %s", arg,
+				Tk_PathName(pwPtr->tkwin)));
+			Tcl_SetErrorCode(interp, "TK", "GEOMETRY",
+				"HIERARCHY", NULL);
 			return TCL_ERROR;
 		    }
 		}
@@ -862,9 +864,10 @@ ConfigureSlaves(
      */
 
     if (haveLoc && index == -1) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "window \"", Tk_PathName(tkwin),
-		"\" is not managed by ", Tk_PathName(pwPtr->tkwin), NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"window \"%s\" is not managed by %s",
+		Tk_PathName(tkwin), Tk_PathName(pwPtr->tkwin)));
+	Tcl_SetErrorCode(interp, "TK", "PANEDWINDOW", "UNMANAGED", NULL);
 	Tk_FreeConfigOptions((char *) &options, pwPtr->slaveOpts,
 		pwPtr->tkwin);
 	return TCL_ERROR;
@@ -1086,7 +1089,6 @@ PanedWindowSashCommand(
 	return TCL_ERROR;
     }
 
-    Tcl_ResetResult(interp);
     switch ((enum sashOptions) index) {
     case SASH_COORD:
 	if (objc != 4) {
@@ -1099,8 +1101,9 @@ PanedWindowSashCommand(
 	}
 
 	if (!ValidSashIndex(pwPtr, sash)) {
-	    Tcl_ResetResult(interp);
-	    Tcl_SetResult(interp, "invalid sash index", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "invalid sash index", -1));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "SASH_INDEX", NULL);
 	    return TCL_ERROR;
 	}
 	slavePtr = pwPtr->slaves[sash];
@@ -1121,8 +1124,9 @@ PanedWindowSashCommand(
 	}
 
 	if (!ValidSashIndex(pwPtr, sash)) {
-	    Tcl_ResetResult(interp);
-	    Tcl_SetResult(interp, "invalid sash index", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "invalid sash index", -1));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "SASH_INDEX", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -1156,8 +1160,9 @@ PanedWindowSashCommand(
 	}
 
 	if (!ValidSashIndex(pwPtr, sash)) {
-	    Tcl_ResetResult(interp);
-	    Tcl_SetResult(interp, "invalid sash index", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "invalid sash index", -1));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "SASH_INDEX", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -2398,10 +2403,11 @@ SetSticky(
 	    case ' ': case ',': case '\t': case '\r': case '\n':
 		break;
 	    default:
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "bad stickyness value \"",
-			Tcl_GetString(*value), "\": must be a string ",
-			"containing zero or more of n, e, s, and w", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"bad stickyness value \"%s\": must be a string"
+			" containing zero or more of n, e, s, and w",
+			Tcl_GetString(*value)));
+		Tcl_SetErrorCode(interp, "TK", "VALUE", "STICKY", NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -2654,7 +2660,7 @@ MoveSash(
  *	None.
  *
  * Side effects:
- *	When the window gets deleted, internal structures get cleaned up. Whena
+ *	When the window gets deleted, internal structures get cleaned up. When
  *	it gets exposed, it is redisplayed.
  *
  *--------------------------------------------------------------
@@ -2958,10 +2964,8 @@ PanedWindowIdentifyCoords(
     Tcl_Interp *interp,		/* Interpreter in which to store result. */
     int x, int y)		/* Coordinates of the point to identify. */
 {
-    Tcl_Obj *list;
     int i, sashHeight, sashWidth, thisx, thisy;
     int found, isHandle, lpad, rpad, tpad, bpad;
-    list = Tcl_NewObj();
 
     if (pwPtr->orient == ORIENT_HORIZONTAL) {
 	if (Tk_IsMapped(pwPtr->tkwin)) {
@@ -3036,16 +3040,17 @@ PanedWindowIdentifyCoords(
     }
 
     /*
-     * Set results.
+     * Set results. Note that the empty string is the default (this function
+     * is called inside the implementation of a command).
      */
 
     if (found != -1) {
-	Tcl_ListObjAppendElement(interp, list, Tcl_NewIntObj(found));
-	Tcl_ListObjAppendElement(interp, list, Tcl_NewStringObj(
-		(isHandle ? "handle" : "sash"), -1));
-    }
+	Tcl_Obj *list[2];
 
-    Tcl_SetObjResult(interp, list);
+	list[0] = Tcl_NewIntObj(found);
+	list[1] = Tcl_NewStringObj((isHandle ? "handle" : "sash"), -1);
+	Tcl_SetObjResult(interp, Tcl_NewListObj(2, list));
+    }
     return TCL_OK;
 }
 
diff --git a/generic/tkPlace.c b/generic/tkPlace.c
index 22072ce..afba488 100644
--- a/generic/tkPlace.c
+++ b/generic/tkPlace.c
@@ -343,7 +343,7 @@ Tk_PlaceObjCmd(
 
 	    for (slavePtr = masterPtr->slavePtr; slavePtr != NULL;
 		    slavePtr = slavePtr->nextPtr) {
-		Tcl_ListObjAppendElement(interp, listPtr,
+		Tcl_ListObjAppendElement(NULL, listPtr,
 			TkNewWindowObj(slavePtr->tkwin));
 	    }
 	    Tcl_SetObjResult(interp, listPtr);
@@ -619,8 +619,10 @@ ConfigureSlave(
     Tk_Window masterWin = (Tk_Window) NULL;
 
     if (Tk_TopWinHierarchy(tkwin)) {
-	Tcl_AppendResult(interp, "can't use placer on top-level window \"",
-		Tk_PathName(tkwin), "\"; use wm command instead", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't use placer on top-level window \"%s\"; use "
+		"wm command instead", Tk_PathName(tkwin)));
+	Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "TOPLEVEL", NULL);
 	return TCL_ERROR;
     }
 
@@ -652,7 +654,7 @@ ConfigureSlave(
 	slavePtr->flags |= CHILD_WIDTH;
     }
 
-    if (((mask & IN_MASK) == 0) && (slavePtr->masterPtr != NULL)) {
+    if (!(mask & IN_MASK) && (slavePtr->masterPtr != NULL)) {
 	/*
 	 * If no -in option was passed and the slave is already placed then
 	 * just recompute the placement.
@@ -678,16 +680,18 @@ ConfigureSlave(
 		break;
 	    }
 	    if (Tk_TopWinHierarchy(ancestor)) {
-		Tcl_AppendResult(interp, "can't place ",
-			Tk_PathName(slavePtr->tkwin), " relative to ",
-			Tk_PathName(tkwin), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"can't place %s relative to %s",
+			Tk_PathName(slavePtr->tkwin), Tk_PathName(tkwin)));
+		Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "HIERARCHY", NULL);
 		goto error;
 	    }
 	}
 	if (slavePtr->tkwin == tkwin) {
-	    Tcl_AppendResult(interp, "can't place ",
-		    Tk_PathName(slavePtr->tkwin), " relative to itself",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't place %s relative to itself",
+		    Tk_PathName(slavePtr->tkwin)));
+	    Tcl_SetErrorCode(interp, "TK", "GEOMETRY", "LOOP", NULL);
 	    goto error;
 	}
 	if ((slavePtr->masterPtr != NULL)
@@ -771,54 +775,50 @@ PlaceInfoCommand(
     Tcl_Interp *interp,		/* Interp into which to place result. */
     Tk_Window tkwin)		/* Token for the window to get info on. */
 {
-    char buffer[32 + TCL_INTEGER_SPACE];
     Slave *slavePtr;
+    Tcl_Obj *infoObj;
 
     slavePtr = FindSlave(tkwin);
     if (slavePtr == NULL) {
 	return TCL_OK;
     }
+    infoObj = Tcl_NewObj();
     if (slavePtr->masterPtr != NULL) {
-	Tcl_AppendElement(interp, "-in");
-	Tcl_AppendElement(interp, Tk_PathName(slavePtr->masterPtr->tkwin));
+	Tcl_AppendToObj(infoObj, "-in", -1);
+	Tcl_ListObjAppendElement(NULL, infoObj,
+		TkNewWindowObj(slavePtr->masterPtr->tkwin));
+	Tcl_AppendToObj(infoObj, " ", -1);
     }
-    sprintf(buffer, " -x %d", slavePtr->x);
-    Tcl_AppendResult(interp, buffer, NULL);
-    sprintf(buffer, " -relx %.4g", slavePtr->relX);
-    Tcl_AppendResult(interp, buffer, NULL);
-    sprintf(buffer, " -y %d", slavePtr->y);
-    Tcl_AppendResult(interp, buffer, NULL);
-    sprintf(buffer, " -rely %.4g", slavePtr->relY);
-    Tcl_AppendResult(interp, buffer, NULL);
+    Tcl_AppendPrintfToObj(infoObj,
+	    "-x %d -relx %.4g -y %d -rely %.4g",
+	    slavePtr->x, slavePtr->relX, slavePtr->y, slavePtr->relY);
     if (slavePtr->flags & CHILD_WIDTH) {
-	sprintf(buffer, " -width %d", slavePtr->width);
-	Tcl_AppendResult(interp, buffer, NULL);
+	Tcl_AppendPrintfToObj(infoObj, " -width %d", slavePtr->width);
     } else {
-	Tcl_AppendResult(interp, " -width {}", NULL);
+	Tcl_AppendToObj(infoObj, " -width {}", -1);
     }
     if (slavePtr->flags & CHILD_REL_WIDTH) {
-	sprintf(buffer, " -relwidth %.4g", slavePtr->relWidth);
-	Tcl_AppendResult(interp, buffer, NULL);
+	Tcl_AppendPrintfToObj(infoObj,
+		" -relwidth %.4g", slavePtr->relWidth);
     } else {
-	Tcl_AppendResult(interp, " -relwidth {}", NULL);
+	Tcl_AppendToObj(infoObj, " -relwidth {}", -1);
     }
     if (slavePtr->flags & CHILD_HEIGHT) {
-	sprintf(buffer, " -height %d", slavePtr->height);
-	Tcl_AppendResult(interp, buffer, NULL);
+	Tcl_AppendPrintfToObj(infoObj, " -height %d", slavePtr->height);
     } else {
-	Tcl_AppendResult(interp, " -height {}", NULL);
+	Tcl_AppendToObj(infoObj, " -height {}", -1);
     }
     if (slavePtr->flags & CHILD_REL_HEIGHT) {
-	sprintf(buffer, " -relheight %.4g", slavePtr->relHeight);
-	Tcl_AppendResult(interp, buffer, NULL);
+	Tcl_AppendPrintfToObj(infoObj,
+		" -relheight %.4g", slavePtr->relHeight);
     } else {
-	Tcl_AppendResult(interp, " -relheight {}", NULL);
+	Tcl_AppendToObj(infoObj, " -relheight {}", -1);
     }
 
-    Tcl_AppendElement(interp, "-anchor");
-    Tcl_AppendElement(interp, Tk_NameOfAnchor(slavePtr->anchor));
-    Tcl_AppendElement(interp, "-bordermode");
-    Tcl_AppendElement(interp, borderModeStrings[slavePtr->borderMode]);
+    Tcl_AppendPrintfToObj(infoObj, " -anchor %s -bordermode %s",
+	    Tk_NameOfAnchor(slavePtr->anchor),
+	    borderModeStrings[slavePtr->borderMode]);
+    Tcl_SetObjResult(interp, infoObj);
     return TCL_OK;
 }
 
@@ -1183,8 +1183,8 @@ PlaceRequestProc(
     Slave *slavePtr = clientData;
     Master *masterPtr;
 
-    if (((slavePtr->flags & (CHILD_WIDTH|CHILD_REL_WIDTH)) != 0)
-	    && ((slavePtr->flags & (CHILD_HEIGHT|CHILD_REL_HEIGHT)) != 0)) {
+    if ((slavePtr->flags & (CHILD_WIDTH|CHILD_REL_WIDTH))
+	    && (slavePtr->flags & (CHILD_HEIGHT|CHILD_REL_HEIGHT))) {
 	return;
     }
     masterPtr = slavePtr->masterPtr;
diff --git a/generic/tkPointer.c b/generic/tkPointer.c
index eab6e48..451373d 100644
--- a/generic/tkPointer.c
+++ b/generic/tkPointer.c
@@ -286,7 +286,7 @@ Tk_UpdatePointer(
 			tsdPtr->restrictWinPtr = winPtr;
 			TkpSetCapture(tsdPtr->restrictWinPtr);
 
-		    } else if ((tsdPtr->lastState & ALL_BUTTONS) == 0) {
+		    } else if (!(tsdPtr->lastState & ALL_BUTTONS)) {
 			/*
 			 * Mouse is in a non-button grab, so ensure the button
 			 * grab is inside the grab tree.
diff --git a/generic/tkRectOval.c b/generic/tkRectOval.c
index 630737c..a51ca33 100644
--- a/generic/tkRectOval.c
+++ b/generic/tkRectOval.c
@@ -318,17 +318,13 @@ RectOvalCoords(
      */
 
     if (objc == 0) {
-	Tcl_Obj *obj = Tcl_NewObj();
-
-	Tcl_ListObjAppendElement(NULL, obj,
-		Tcl_NewDoubleObj(rectOvalPtr->bbox[0]));
-	Tcl_ListObjAppendElement(NULL, obj,
-		Tcl_NewDoubleObj(rectOvalPtr->bbox[1]));
-	Tcl_ListObjAppendElement(NULL, obj,
-		Tcl_NewDoubleObj(rectOvalPtr->bbox[2]));
-	Tcl_ListObjAppendElement(NULL, obj,
-		Tcl_NewDoubleObj(rectOvalPtr->bbox[3]));
-	Tcl_SetObjResult(interp, obj);
+	Tcl_Obj *bbox[4];
+
+	bbox[0] = Tcl_NewDoubleObj(rectOvalPtr->bbox[0]);
+	bbox[1] = Tcl_NewDoubleObj(rectOvalPtr->bbox[1]);
+	bbox[2] = Tcl_NewDoubleObj(rectOvalPtr->bbox[2]);
+	bbox[3] = Tcl_NewDoubleObj(rectOvalPtr->bbox[3]);
+	Tcl_SetObjResult(interp, Tcl_NewListObj(4, bbox));
 	return TCL_OK;
     }
 
@@ -348,10 +344,11 @@ RectOvalCoords(
      */
 
     if (objc != 4) {
-	char buf[64 + TCL_INTEGER_SPACE];
-
-	sprintf(buf, "wrong # coordinates: expected 0 or 4, got %d", objc);
-	Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"wrong # coordinates: expected 0 or 4, got %d", objc));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS",
+		(rectOvalPtr->header.typePtr == &tkRectangleType
+			? "RECTANGLE" : "OVAL"), NULL);
 	return TCL_ERROR;
     }
 
@@ -515,9 +512,10 @@ ConfigureRectOval(
 	}
 #ifdef MAC_OSX_TK
 	/*
-	 * Mac OS X CG drawing needs access to the outline linewidth
-	 * even for fills (as linewidth controls antialiasing).
+	 * Mac OS X CG drawing needs access to the outline linewidth even for
+	 * fills (as linewidth controls antialiasing).
 	 */
+
 	gcValues.line_width = rectOvalPtr->outline.gc != None ?
 		rectOvalPtr->outline.gc->line_width : 0;
 	mask |= GCLineWidth;
@@ -677,7 +675,7 @@ ComputeRectOvalBbox(
 	bloat = 1;
 #else
 	bloat = 0;
-#endif
+#endif /* __WIN32__ */
     } else {
 #ifdef MAC_OSX_TK
 	/*
@@ -689,7 +687,7 @@ ComputeRectOvalBbox(
 	bloat = (int) (width+1.5)/2;
 #else
 	bloat = (int) (width+1)/2;
-#endif
+#endif /* MAC_OSX_TK */
     }
 
     /*
@@ -757,9 +755,9 @@ DisplayRectOval(
      * will die if it isn't.
      */
 
-    Tk_CanvasDrawableCoords(canvas, rectOvalPtr->bbox[0], rectOvalPtr->bbox[1],
+    Tk_CanvasDrawableCoords(canvas, rectOvalPtr->bbox[0],rectOvalPtr->bbox[1],
 	    &x1, &y1);
-    Tk_CanvasDrawableCoords(canvas, rectOvalPtr->bbox[2], rectOvalPtr->bbox[3],
+    Tk_CanvasDrawableCoords(canvas, rectOvalPtr->bbox[2],rectOvalPtr->bbox[3],
 	    &x2, &y2);
     if (x2 <= x1) {
 	x2 = x1+1;
@@ -1293,13 +1291,14 @@ RectOvalToPostscript(
 				 * information; 0 means final Postscript is
 				 * being created. */
 {
-    char pathCmd[500];
+    Tcl_Obj *pathObj, *psObj;
     RectOvalItem *rectOvalPtr = (RectOvalItem *) itemPtr;
     double y1, y2;
     XColor *color;
     XColor *fillColor;
     Pixmap fillStipple;
     Tk_State state = itemPtr->state;
+    Tcl_InterpState interpState;
 
     y1 = Tk_CanvasPsY(canvas, rectOvalPtr->bbox[1]);
     y2 = Tk_CanvasPsY(canvas, rectOvalPtr->bbox[3]);
@@ -1310,12 +1309,23 @@ RectOvalToPostscript(
      */
 
     if (rectOvalPtr->header.typePtr == &tkRectangleType) {
-	sprintf(pathCmd, "%.15g %.15g moveto %.15g 0 rlineto 0 %.15g rlineto %.15g 0 rlineto closepath\n",
+	pathObj = Tcl_ObjPrintf(
+		"%.15g %.15g moveto "
+		"%.15g 0 rlineto "
+		"0 %.15g rlineto "
+		"%.15g 0 rlineto "
+		"closepath\n",
 		rectOvalPtr->bbox[0], y1,
-		rectOvalPtr->bbox[2]-rectOvalPtr->bbox[0], y2-y1,
+		rectOvalPtr->bbox[2]-rectOvalPtr->bbox[0],
+		y2-y1,
 		rectOvalPtr->bbox[0]-rectOvalPtr->bbox[2]);
     } else {
-	sprintf(pathCmd, "matrix currentmatrix\n%.15g %.15g translate %.15g %.15g scale 1 0 moveto 0 0 1 0 360 arc\nsetmatrix\n",
+	pathObj = Tcl_ObjPrintf(
+		"matrix currentmatrix\n"
+		"%.15g %.15g translate "
+		"%.15g %.15g scale "
+		"1 0 moveto 0 0 1 0 360 arc\n"
+		"setmatrix\n",
 		(rectOvalPtr->bbox[0] + rectOvalPtr->bbox[2])/2, (y1 + y2)/2,
 		(rectOvalPtr->bbox[2] - rectOvalPtr->bbox[0])/2, (y1 - y2)/2);
     }
@@ -1349,24 +1359,38 @@ RectOvalToPostscript(
     }
 
     /*
+     * Make our working space.
+     */
+
+    psObj = Tcl_NewObj();
+    interpState = Tcl_SaveInterpState(interp, TCL_OK);
+
+    /*
      * First draw the filled area of the rectangle.
      */
 
     if (fillColor != NULL) {
-	Tcl_AppendResult(interp, pathCmd, NULL);
+	Tcl_AppendObjToObj(psObj, pathObj);
+
+	Tcl_ResetResult(interp);
 	if (Tk_CanvasPsColor(interp, canvas, fillColor) != TCL_OK) {
-	    return TCL_ERROR;
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
+
 	if (fillStipple != None) {
-	    Tcl_AppendResult(interp, "clip ", NULL);
+	    Tcl_AppendToObj(psObj, "clip ", -1);
+
+	    Tcl_ResetResult(interp);
 	    if (Tk_CanvasPsStipple(interp, canvas, fillStipple) != TCL_OK) {
-		return TCL_ERROR;
+		goto error;
 	    }
+	    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
 	    if (color != NULL) {
-		Tcl_AppendResult(interp, "grestore gsave\n", NULL);
+		Tcl_AppendToObj(psObj, "grestore gsave\n", -1);
 	    }
 	} else {
-	    Tcl_AppendResult(interp, "fill\n", NULL);
+	    Tcl_AppendToObj(psObj, "fill\n", -1);
 	}
     }
 
@@ -1375,14 +1399,32 @@ RectOvalToPostscript(
      */
 
     if (color != NULL) {
-	Tcl_AppendResult(interp, pathCmd, "0 setlinejoin 2 setlinecap\n",
-		NULL);
+	Tcl_AppendObjToObj(psObj, pathObj);
+	Tcl_AppendToObj(psObj, "0 setlinejoin 2 setlinecap\n", -1);
+
+	Tcl_ResetResult(interp);
 	if (Tk_CanvasPsOutline(canvas, itemPtr,
 		&rectOvalPtr->outline)!= TCL_OK) {
-	    return TCL_ERROR;
+	    goto error;
 	}
+	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
     }
+
+    /*
+     * Plug the accumulated postscript back into the result.
+     */
+
+    (void) Tcl_RestoreInterpState(interp, interpState);
+    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    Tcl_DecrRefCount(psObj);
+    Tcl_DecrRefCount(pathObj);
     return TCL_OK;
+
+  error:
+    Tcl_DiscardInterpState(interpState);
+    Tcl_DecrRefCount(psObj);
+    Tcl_DecrRefCount(pathObj);
+    return TCL_ERROR;
 }
 
 /*
diff --git a/generic/tkScale.c b/generic/tkScale.c
index 5e577e9..3ca4a67 100644
--- a/generic/tkScale.c
+++ b/generic/tkScale.c
@@ -376,6 +376,7 @@ ScaleWidgetObjCmd(
     case COMMAND_COORDS: {
 	int x, y;
 	double value;
+	Tcl_Obj *coords[2];
 
 	if ((objc != 2) && (objc != 3)) {
 	    Tcl_WrongNumArgs(interp, 1, objv, "coords ?value?");
@@ -397,7 +398,9 @@ ScaleWidgetObjCmd(
 	    y = scalePtr->horizTroughY + scalePtr->width/2
 		    + scalePtr->borderWidth;
 	}
-	Tcl_SetObjResult(interp, Tcl_ObjPrintf("%d %d", x, y));
+	coords[0] = Tcl_NewIntObj(x);
+	coords[1] = Tcl_NewIntObj(y);
+	Tcl_SetObjResult(interp, Tcl_NewListObj(2, coords));
 	break;
     }
     case COMMAND_GET: {
@@ -421,7 +424,8 @@ ScaleWidgetObjCmd(
 	break;
     }
     case COMMAND_IDENTIFY: {
-	int x, y, thing;
+	int x, y;
+	const char *zone = "";
 
 	if (objc != 4) {
 	    Tcl_WrongNumArgs(interp, 1, objv, "identify x y");
@@ -431,18 +435,12 @@ ScaleWidgetObjCmd(
 		|| (Tcl_GetIntFromObj(interp, objv[3], &y) != TCL_OK)) {
 	    goto error;
 	}
-	thing = TkpScaleElement(scalePtr, x,y);
-	switch (thing) {
-	case TROUGH1:
-	    Tcl_SetResult(interp, "trough1", TCL_STATIC);
-	    break;
-	case SLIDER:
-	    Tcl_SetResult(interp, "slider", TCL_STATIC);
-	    break;
-	case TROUGH2:
-	    Tcl_SetResult(interp, "trough2", TCL_STATIC);
-	    break;
+	switch (TkpScaleElement(scalePtr, x, y)) {
+	case TROUGH1:	zone = "trough1"; break;
+	case SLIDER:	zone = "slider";  break;
+	case TROUGH2:	zone = "trough2"; break;
 	}
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(zone, -1));
 	break;
     }
     case COMMAND_SET: {
diff --git a/generic/tkScrollbar.c b/generic/tkScrollbar.c
index 49ddca0..2d91db6 100644
--- a/generic/tkScrollbar.c
+++ b/generic/tkScrollbar.c
@@ -12,6 +12,10 @@
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  */
 
+/*
+ * TODO: Convert scrollbars to the Tcl_Obj API.
+ */
+
 #include "tkInt.h"
 #include "tkScrollbar.h"
 #include "default.h"
@@ -132,8 +136,10 @@ Tk_ScrollbarCmd(
     Tk_Window newWin;
 
     if (argc < 2) {
-	Tcl_AppendResult(interp, "wrong # args: should be \"",
-		argv[0], " pathName ?-option value ...?\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"wrong # args: should be \"%s pathName ?-option value ...?\"",
+		argv[0]));
+	Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	return TCL_ERROR;
     }
 
@@ -230,8 +236,9 @@ ScrollbarWidgetCmd(
     int c;
 
     if (argc < 2) {
-	Tcl_AppendResult(interp, "wrong # args: should be \"",
-		argv[0], " option ?arg ...?\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"wrong # args: should be \"%s option ?arg ...?\"", argv[0]));
+	Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	return TCL_ERROR;
     }
     Tcl_Preserve(scrollPtr);
@@ -239,23 +246,23 @@ ScrollbarWidgetCmd(
     length = strlen(argv[1]);
     if ((c == 'a') && (strncmp(argv[1], "activate", length) == 0)) {
 	int oldActiveField;
+
 	if (argc == 2) {
+	    const char *zone = "";
+
 	    switch (scrollPtr->activeField) {
-	    case TOP_ARROW:
-		Tcl_SetResult(interp, "arrow1", TCL_STATIC);
-		break;
-	    case SLIDER:
-		Tcl_SetResult(interp, "slider", TCL_STATIC);
-		break;
-	    case BOTTOM_ARROW:
-		Tcl_SetResult(interp, "arrow2", TCL_STATIC);
-		break;
+	    case TOP_ARROW:	zone = "arrow1"; break;
+	    case SLIDER:	zone = "slider"; break;
+	    case BOTTOM_ARROW:	zone = "arrow2"; break;
 	    }
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(zone, -1));
 	    goto done;
 	}
 	if (argc != 3) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"",
-		    argv[0], " activate element\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # args: should be \"%s activate element\"",
+		    argv[0]));
+	    Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	    goto error;
 	}
 	c = argv[2][0];
@@ -276,9 +283,9 @@ ScrollbarWidgetCmd(
     } else if ((c == 'c') && (strncmp(argv[1], "cget", length) == 0)
 	    && (length >= 2)) {
 	if (argc != 3) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"",
-		    argv[0], " cget option\"",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # args: should be \"%s cget option\"", argv[0]));
+	    Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	    goto error;
 	}
 	result = Tk_ConfigureValue(interp, scrollPtr->tkwin,
@@ -300,8 +307,10 @@ ScrollbarWidgetCmd(
 	double fraction;
 
 	if (argc != 4) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"",
-		    argv[0], " delta xDelta yDelta\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # args: should be \"%s delta xDelta yDelta\"",
+		    argv[0]));
+	    Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	    goto error;
 	}
 	if ((Tcl_GetInt(interp, argv[2], &xDelta) != TCL_OK)
@@ -328,8 +337,9 @@ ScrollbarWidgetCmd(
 	double fraction;
 
 	if (argc != 4) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"",
-		    argv[0], " fraction x y\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # args: should be \"%s fraction x y\"", argv[0]));
+	    Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	    goto error;
 	}
 	if ((Tcl_GetInt(interp, argv[2], &x) != TCL_OK)
@@ -357,20 +367,19 @@ ScrollbarWidgetCmd(
 	}
 	Tcl_SetObjResult(interp, Tcl_NewDoubleObj(fraction));
     } else if ((c == 'g') && (strncmp(argv[1], "get", length) == 0)) {
+	Tcl_Obj *resObjs[4];
+
 	if (argc != 2) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"",
-		    argv[0], " get\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # args: should be \"%s get\"", argv[0]));
+	    Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	    goto error;
 	}
 	if (scrollPtr->flags & NEW_STYLE_COMMANDS) {
-	    Tcl_Obj *resObjs[2];
-
 	    resObjs[0] = Tcl_NewDoubleObj(scrollPtr->firstFraction);
 	    resObjs[1] = Tcl_NewDoubleObj(scrollPtr->lastFraction);
 	    Tcl_SetObjResult(interp, Tcl_NewListObj(2, resObjs));
 	} else {
-	    Tcl_Obj *resObjs[4];
-
 	    resObjs[0] = Tcl_NewIntObj(scrollPtr->totalUnits);
 	    resObjs[1] = Tcl_NewIntObj(scrollPtr->windowUnits);
 	    resObjs[2] = Tcl_NewIntObj(scrollPtr->firstUnit);
@@ -378,35 +387,27 @@ ScrollbarWidgetCmd(
 	    Tcl_SetObjResult(interp, Tcl_NewListObj(4, resObjs));
 	}
     } else if ((c == 'i') && (strncmp(argv[1], "identify", length) == 0)) {
-	int x, y, thing;
+	int x, y;
+	const char *zone = "";
 
 	if (argc != 4) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"",
-		    argv[0], " identify x y\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # args: should be \"%s identify x y\"", argv[0]));
+	    Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	    goto error;
 	}
 	if ((Tcl_GetInt(interp, argv[2], &x) != TCL_OK)
 		|| (Tcl_GetInt(interp, argv[3], &y) != TCL_OK)) {
 	    goto error;
 	}
-	thing = TkpScrollbarPosition(scrollPtr, x,y);
-	switch (thing) {
-	case TOP_ARROW:
-	    Tcl_SetResult(interp, "arrow1", TCL_STATIC);
-	    break;
-	case TOP_GAP:
-	    Tcl_SetResult(interp, "trough1", TCL_STATIC);
-	    break;
-	case SLIDER:
-	    Tcl_SetResult(interp, "slider", TCL_STATIC);
-	    break;
-	case BOTTOM_GAP:
-	    Tcl_SetResult(interp, "trough2", TCL_STATIC);
-	    break;
-	case BOTTOM_ARROW:
-	    Tcl_SetResult(interp, "arrow2", TCL_STATIC);
-	    break;
+	switch (TkpScrollbarPosition(scrollPtr, x, y)) {
+	case TOP_ARROW:		zone = "arrow1";  break;
+	case TOP_GAP:		zone = "trough1"; break;
+	case SLIDER:		zone = "slider";  break;
+	case BOTTOM_GAP:	zone = "trough2"; break;
+	case BOTTOM_ARROW:	zone = "arrow2";  break;
 	}
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(zone, -1));
     } else if ((c == 's') && (strncmp(argv[1], "set", length) == 0)) {
 	int totalUnits, windowUnits, firstUnit, lastUnit;
 
@@ -473,18 +474,22 @@ ScrollbarWidgetCmd(
 	    }
 	    scrollPtr->flags &= ~NEW_STYLE_COMMANDS;
 	} else {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"",
-		    argv[0], " set firstFraction lastFraction\" or \"",
-		    argv[0],
-		    " set totalUnits windowUnits firstUnit lastUnit\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # args: should be "
+		    "\"%s set firstFraction lastFraction\" or "
+		    "\"%s set totalUnits windowUnits firstUnit lastUnit\"",
+		    argv[0], argv[0]));
+	    Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	    goto error;
 	}
 	TkpComputeScrollbarGeometry(scrollPtr);
 	TkScrollbarEventuallyRedraw(scrollPtr);
     } else {
-	Tcl_AppendResult(interp, "bad option \"", argv[1],
-		"\": must be activate, cget, configure, delta, fraction, ",
-		"get, identify, or set", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad option \"%s\": must be activate, cget, configure,"
+		" delta, fraction, get, identify, or set", argv[1]));
+	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "option",
+		argv[1], NULL);
 	goto error;
     }
 
@@ -538,7 +543,7 @@ ConfigureScrollbar(
      */
 
     if (scrollPtr->command != NULL) {
-        scrollPtr->commandSize = (int)strlen(scrollPtr->command);
+        scrollPtr->commandSize = (int) strlen(scrollPtr->command);
     } else {
 	scrollPtr->commandSize = 0;
     }
@@ -602,8 +607,7 @@ TkScrollbarEventProc(
 	 * Tk_FreeOptions handle all the standard option-related stuff.
 	 */
 
-	Tk_FreeOptions(configSpecs, (char *) scrollPtr,
-		scrollPtr->display, 0);
+	Tk_FreeOptions(configSpecs, (char*) scrollPtr, scrollPtr->display, 0);
 	Tcl_EventuallyFree(scrollPtr, TCL_DYNAMIC);
     } else if (eventPtr->type == ConfigureNotify) {
 	TkpComputeScrollbarGeometry(scrollPtr);
@@ -683,10 +687,10 @@ void
 TkScrollbarEventuallyRedraw(
     TkScrollbar *scrollPtr)	/* Information about widget. */
 {
-    if ((scrollPtr->tkwin == NULL) || (!Tk_IsMapped(scrollPtr->tkwin))) {
+    if ((scrollPtr->tkwin == NULL) || !Tk_IsMapped(scrollPtr->tkwin)) {
 	return;
     }
-    if ((scrollPtr->flags & REDRAW_PENDING) == 0) {
+    if (!(scrollPtr->flags & REDRAW_PENDING)) {
 	Tcl_DoWhenIdle(TkpDisplayScrollbar, scrollPtr);
 	scrollPtr->flags |= REDRAW_PENDING;
     }
diff --git a/generic/tkSelect.c b/generic/tkSelect.c
index ee52ba1..2414b3d 100644
--- a/generic/tkSelect.c
+++ b/generic/tkSelect.c
@@ -638,9 +638,10 @@ Tk_GetSelection(
 	    clientData);
 
   cantget:
-    Tcl_AppendResult(interp, Tk_GetAtomName(tkwin, selection),
-	    " selection doesn't exist or form \"",
-	    Tk_GetAtomName(tkwin, target), "\" not defined", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "%s selection doesn't exist or form \"%s\" not defined",
+	    Tk_GetAtomName(tkwin, selection),
+	    Tk_GetAtomName(tkwin, target)));
     return TCL_ERROR;
 }
 
@@ -708,8 +709,9 @@ Tk_SelectionObjCmd(
 		break;
 	    }
 	    if (count < 2) {
-		Tcl_AppendResult(interp, "value for \"", string,
-			"\" missing", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"value for \"%s\" missing", string));
+		Tcl_SetErrorCode(interp, "TK", "SELECTION", "VALUE", NULL);
 		return TCL_ERROR;
 	    }
 
@@ -767,8 +769,9 @@ Tk_SelectionObjCmd(
 		break;
 	    }
 	    if (count < 2) {
-		Tcl_AppendResult(interp, "value for \"", string,
-			"\" missing", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"value for \"%s\" missing", string));
+		Tcl_SetErrorCode(interp, "TK", "SELECTION", "VALUE", NULL);
 		return TCL_ERROR;
 	    }
 
@@ -844,8 +847,9 @@ Tk_SelectionObjCmd(
 		break;
 	    }
 	    if (count < 2) {
-		Tcl_AppendResult(interp, "value for \"", string,
-			"\" missing", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"value for \"%s\" missing", string));
+		Tcl_SetErrorCode(interp, "TK", "SELECTION", "VALUE", NULL);
 		return TCL_ERROR;
 	    }
 
@@ -868,7 +872,8 @@ Tk_SelectionObjCmd(
 	}
 
 	if ((count < 2) || (count > 4)) {
-	    Tcl_WrongNumArgs(interp, 2, objv, "?-option value ...? window command");
+	    Tcl_WrongNumArgs(interp, 2, objv,
+		    "?-option value ...? window command");
 	    return TCL_ERROR;
 	}
 	tkwin = Tk_NameToWindow(interp, Tcl_GetString(objs[0]), tkwin);
@@ -929,8 +934,9 @@ Tk_SelectionObjCmd(
 		break;
 	    }
 	    if (count < 2) {
-		Tcl_AppendResult(interp, "value for \"", string,
-			"\" missing", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"value for \"%s\" missing", string));
+		Tcl_SetErrorCode(interp, "TK", "SELECTION", "VALUE", NULL);
 		return TCL_ERROR;
 	    }
 
@@ -972,7 +978,7 @@ Tk_SelectionObjCmd(
 	    if (tkwin == NULL) {
 		return TCL_ERROR;
 	    }
-	    winPtr = (TkWindow *)tkwin;
+	    winPtr = (TkWindow *) tkwin;
 	    for (infoPtr = winPtr->dispPtr->selectionInfoPtr;
 		    infoPtr != NULL; infoPtr = infoPtr->nextPtr) {
 		if (infoPtr->selection == selection) {
@@ -986,7 +992,7 @@ Tk_SelectionObjCmd(
 
 	    if ((infoPtr != NULL)
 		    && (infoPtr->owner != winPtr->dispPtr->clipWindow)) {
-		Tcl_SetResult(interp, Tk_PathName(infoPtr->owner), TCL_STATIC);
+		Tcl_SetObjResult(interp, TkNewWindowObj(infoPtr->owner));
 	    }
 	    return TCL_OK;
 	}
@@ -1285,7 +1291,7 @@ SelGetProc(
 				 * selection. */
     Tcl_Interp *interp,		/* Interpreter used for error reporting (not
 				 * used). */
-    const char *portion)		/* New information to be appended. */
+    const char *portion)	/* New information to be appended. */
 {
     Tcl_DStringAppend(clientData, portion, -1);
     return TCL_OK;
@@ -1320,13 +1326,11 @@ HandleTclCommand(
     int maxBytes)		/* Maximum # of bytes to store at buffer. */
 {
     CommandInfo *cmdInfoPtr = clientData;
-    int spaceNeeded, length;
-#define MAX_STATIC_SIZE 100
-    char staticSpace[MAX_STATIC_SIZE];
-    char *command;
+    int length;
+    Tcl_Obj *command;
     const char *string;
     Tcl_Interp *interp = cmdInfoPtr->interp;
-    Tcl_DString oldResult;
+    Tcl_InterpState savedState;
     int extraBytes, charOffset, count, numChars, code;
     const char *p;
 
@@ -1363,23 +1367,23 @@ HandleTclCommand(
      * the offset and maximum # of bytes.
      */
 
-    spaceNeeded = cmdInfoPtr->cmdLength + 30;
-    if (spaceNeeded < MAX_STATIC_SIZE) {
-	command = staticSpace;
-    } else {
-	command = ckalloc(spaceNeeded);
-    }
-    sprintf(command, "%s %d %d", cmdInfoPtr->command, charOffset, maxBytes);
+    command = Tcl_ObjPrintf("%s %d %d",
+	    cmdInfoPtr->command, charOffset, maxBytes);
+    Tcl_IncrRefCount(command);
 
     /*
      * Execute the command. Be sure to restore the state of the interpreter
      * after executing the command.
      */
 
-    Tcl_DStringInit(&oldResult);
-    Tcl_DStringGetResult(interp, &oldResult);
-    code = Tcl_EvalEx(interp, command, -1, TCL_EVAL_GLOBAL);
+    savedState = Tcl_SaveInterpState(interp, TCL_OK);
+    code = Tcl_EvalObjEx(interp, command, TCL_EVAL_GLOBAL);
+    Tcl_DecrRefCount(command);
     if (code == TCL_OK) {
+	/*
+	 * TODO: This assumes that bytes are characters; that's not true!
+	 */
+
 	string = Tcl_GetStringFromObj(Tcl_GetObjResult(interp), &length);
 	count = (length > maxBytes) ? maxBytes : length;
 	memcpy(buffer, string, (size_t) count);
@@ -1424,11 +1428,7 @@ HandleTclCommand(
 	}
 	count = -1;
     }
-    Tcl_DStringResult(interp, &oldResult);
-
-    if (command != staticSpace) {
-	ckfree(command);
-    }
+    (void) Tcl_RestoreInterpState(interp, savedState);
 
     Tcl_Release(clientData);
     Tcl_Release(interp);
@@ -1498,6 +1498,7 @@ TkSelDefaultSelection(
 		    && (selPtr->target != dispPtr->windowAtom)) {
 		const char *atomString = Tk_GetAtomName((Tk_Window) winPtr,
 			selPtr->target);
+
 		Tcl_DStringAppendElement(&ds, atomString);
 	    }
 	}
@@ -1564,11 +1565,10 @@ LostSelection(
     ClientData clientData)	/* Pointer to LostCommand structure. */
 {
     LostCommand *lostPtr = clientData;
-    Tcl_Obj *objPtr;
-    Tcl_Interp *interp;
+    Tcl_Interp *interp = lostPtr->interp;
+    Tcl_InterpState savedState;
     int code;
 
-    interp = lostPtr->interp;
     Tcl_Preserve(interp);
 
     /*
@@ -1576,19 +1576,13 @@ LostSelection(
      * it after executing the command.
      */
 
-    objPtr = Tcl_GetObjResult(interp);
-    Tcl_IncrRefCount(objPtr);
+    savedState = Tcl_SaveInterpState(interp, TCL_OK);
     Tcl_ResetResult(interp);
-
     code = Tcl_EvalObjEx(interp, lostPtr->cmdObj, TCL_EVAL_GLOBAL);
     if (code != TCL_OK) {
 	Tcl_BackgroundException(interp, code);
     }
-
-    Tcl_SetObjResult(interp, objPtr);
-    Tcl_DecrRefCount(objPtr);
-
-    Tcl_Release(interp);
+    (void) Tcl_RestoreInterpState(interp, savedState);
 
     /*
      * Free the storage for the command, since we're done with it now.
@@ -1596,6 +1590,7 @@ LostSelection(
 
     Tcl_DecrRefCount(lostPtr->cmdObj);
     ckfree(lostPtr);
+    Tcl_Release(interp);
 }
 
 /*
diff --git a/generic/tkStubInit.c b/generic/tkStubInit.c
index 271243e..b1cdd53 100644
--- a/generic/tkStubInit.c
+++ b/generic/tkStubInit.c
@@ -55,7 +55,7 @@ TkpSync(Display *display)
 void
 TkCreateXEventSource(void)
 {
-	TkWinXInit(Tk_GetHINSTANCE());
+    TkWinXInit(Tk_GetHINSTANCE());
 }
 
 #   define TkUnixContainerId 0
@@ -105,7 +105,7 @@ TkpPrintWindowId(
 				 * the hex representation of a pointer. */
     Window window)		/* Window to be printed into buffer. */
 {
-	sprintf(buf, "%#08lx", (unsigned long) (window));
+    sprintf(buf, "%#08lx", (unsigned long) (window));
 }
 
 int
diff --git a/generic/tkStubLib.c b/generic/tkStubLib.c
index 53f177d..b4063b5 100644
--- a/generic/tkStubLib.c
+++ b/generic/tkStubLib.c
@@ -124,9 +124,8 @@ Tk_InitStubs(
     }
 
     if (!stubsPtr) {
-	Tcl_SetResult(interp,
-		"This implementation of Tk does not support stubs",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"this implementation of Tk does not support stubs", -1));
 	return NULL;
     }
 
diff --git a/generic/tkStyle.c b/generic/tkStyle.c
index 76291fa..d5e1407 100644
--- a/generic/tkStyle.c
+++ b/generic/tkStyle.c
@@ -1356,8 +1356,9 @@ Tk_GetStyle(
     entryPtr = Tcl_FindHashEntry(&tsdPtr->styleTable, (name!=NULL?name:""));
     if (entryPtr == NULL) {
 	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "style \"", name, "\" doesn't exist",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "style \"%s\" doesn't exist", name));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "STYLE", name, NULL);
 	}
 	return (Tk_Style) NULL;
     }
diff --git a/generic/tkText.c b/generic/tkText.c
index 56a98e7..e7b1c4d 100644
--- a/generic/tkText.c
+++ b/generic/tkText.c
@@ -760,13 +760,13 @@ TextWidgetObjCmd(
 	} else {
 	    Tcl_Obj *objPtr = Tk_GetOptionValue(interp, (char *) textPtr,
 		    textPtr->optionTable, objv[2], textPtr->tkwin);
+
 	    if (objPtr == NULL) {
 		result = TCL_ERROR;
 		goto done;
-	    } else {
-		Tcl_SetObjResult(interp, objPtr);
-		result = TCL_OK;
 	    }
+	    Tcl_SetObjResult(interp, objPtr);
+	    result = TCL_OK;
 	}
 	break;
     case TEXT_COMPARE: {
@@ -792,12 +792,7 @@ TextWidgetObjCmd(
 	    if ((p[1] == '=') && (p[2] == 0)) {
 		value = (relation <= 0);
 	    } else if (p[1] != 0) {
-	    compareError:
-		Tcl_AppendResult(interp, "bad comparison operator \"",
-			Tcl_GetString(objv[3]),
-			"\": must be <, <=, ==, >=, >, or !=", NULL);
-		result = TCL_ERROR;
-		goto done;
+		goto compareError;
 	    }
 	} else if (p[0] == '>') {
 	    value = (relation > 0);
@@ -815,18 +810,26 @@ TextWidgetObjCmd(
 	}
 	Tcl_SetObjResult(interp, Tcl_NewBooleanObj(value));
 	break;
+
+    compareError:
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad comparison operator \"%s\": must be"
+		" <, <=, ==, >=, >, or !=", Tcl_GetString(objv[3])));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "COMPARISON", NULL);
+	result = TCL_ERROR;
+	goto done;
     }
     case TEXT_CONFIGURE:
 	if (objc <= 3) {
 	    Tcl_Obj *objPtr = Tk_GetOptionInfo(interp, (char *) textPtr,
 		    textPtr->optionTable, ((objc == 3) ? objv[2] : NULL),
 		    textPtr->tkwin);
+
 	    if (objPtr == NULL) {
 		result = TCL_ERROR;
 		goto done;
-	    } else {
-		Tcl_SetObjResult(interp, objPtr);
 	    }
+	    Tcl_SetObjResult(interp, objPtr);
 	} else {
 	    result = ConfigureText(interp, textPtr, objc-2, objv+2);
 	}
@@ -837,7 +840,8 @@ TextWidgetObjCmd(
 	Tcl_Obj *objPtr = NULL;
 
 	if (objc < 4) {
-	    Tcl_WrongNumArgs(interp, 2, objv, "?-option value ...? index1 index2");
+	    Tcl_WrongNumArgs(interp, 2, objv,
+		    "?-option value ...? index1 index2");
 	    result = TCL_ERROR;
 	    goto done;
 	}
@@ -859,15 +863,7 @@ TextWidgetObjCmd(
 	    char c;
 
 	    if (length < 2 || option[0] != '-') {
-	    badOption:
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "bad option \"",
-			Tcl_GetString(objv[i]),
-			"\" must be -chars, -displaychars, -displayindices, ",
-			"-displaylines, -indices, -lines, -update, ",
-			"-xpixels, or -ypixels", NULL);
-		result = TCL_ERROR;
-		goto done;
+		goto badOption;
 	    }
 	    c = option[1];
 	    if (c == 'c' && !strncmp("-chars", option, (unsigned) length)) {
@@ -1037,6 +1033,15 @@ TextWidgetObjCmd(
 	    Tcl_SetObjResult(interp, objPtr);
 	}
 	break;
+
+    badOption:
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad option \"%s\" must be -chars, -displaychars, "
+		"-displayindices, -displaylines, -indices, -lines, -update, "
+		"-xpixels, or -ypixels", Tcl_GetString(objv[i])));
+	Tcl_SetErrorCode(interp, "TK", "TEXT", "INDEX_OPTION", NULL);
+	result = TCL_ERROR;
+	goto done;
     }
     case TEXT_DEBUG:
 	if (objc > 3) {
@@ -1257,7 +1262,7 @@ TextWidgetObjCmd(
 	if (objc > 3) {
 	    name = Tcl_GetStringFromObj(objv[i], &length);
 	    if (length > 1 && name[0] == '-') {
-		if (strncmp("-displaychars", name, (unsigned)length)==0) {
+		if (strncmp("-displaychars", name, (unsigned) length) == 0) {
 		    i++;
 		    visible = 1;
 		    name = Tcl_GetStringFromObj(objv[i], &length);
@@ -1395,9 +1400,10 @@ TextWidgetObjCmd(
 	    goto done;
 	}
 	if (TkTextIndexCmp(indexFromPtr, indexToPtr) > 0) {
-	    Tcl_AppendResult(interp, "Index \"", Tcl_GetString(objv[3]),
-		    "\" before \"", Tcl_GetString(objv[2]),
-		    "\" in the text", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "index \"%s\" before \"%s\" in the text",
+		    Tcl_GetString(objv[3]), Tcl_GetString(objv[2])));
+	    Tcl_SetErrorCode(interp, "TK", "TEXT", "INDEX_ORDER", NULL);
 	    result = TCL_ERROR;
 	    goto done;
 	}
@@ -1663,7 +1669,7 @@ TextPeerCmd(
 	return TCL_ERROR;
     }
 
-    switch ((enum peerOptions)index) {
+    switch ((enum peerOptions) index) {
     case PEER_CREATE:
 	if (objc < 4) {
 	    Tcl_WrongNumArgs(interp, 3, objv, "pathName ?-option value ...?");
@@ -1673,17 +1679,21 @@ TextPeerCmd(
 		objc-2, objv+2);
     case PEER_NAMES: {
 	TkText *tPtr = textPtr->sharedTextPtr->peers;
+	Tcl_Obj *peersObj;
 
 	if (objc > 3) {
 	    Tcl_WrongNumArgs(interp, 3, objv, NULL);
 	    return TCL_ERROR;
 	}
+	peersObj = Tcl_NewObj();
 	while (tPtr != NULL) {
 	    if (tPtr != textPtr) {
-		Tcl_AppendElement(interp, Tk_PathName(tPtr->tkwin));
+		Tcl_ListObjAppendElement(NULL, peersObj,
+			TkNewWindowObj(tPtr->tkwin));
 	    }
 	    tPtr = tPtr->next;
 	}
+	Tcl_SetObjResult(interp, peersObj);
     }
     }
 
@@ -2054,9 +2064,9 @@ ConfigureText(
 	    end = TkBTreeNumLines(textPtr->sharedTextPtr->tree, NULL);
 	}
 	if (start > end) {
-	    Tcl_AppendResult(interp,
-		    "-startline must be less than or equal to -endline",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "-startline must be less than or equal to -endline", -1));
+	    Tcl_SetErrorCode(interp, "TK", "TEXT", "INDEX_ORDER", NULL);
 	    Tk_RestoreSavedOptions(&savedOptions);
 	    return TCL_ERROR;
 	}
@@ -2089,6 +2099,7 @@ ConfigureText(
 		/* Nothing tagged with "sel" */
 	    } else {
 		int line = TkBTreeLinesTo(NULL, search.curIndex.linePtr);
+
 		if (line < start) {
 		    selChanged = 1;
 		} else {
@@ -3657,13 +3668,14 @@ TextSearchCmd(
     SearchSpec searchSpec;
 
     static const char *const switchStrings[] = {
+	"-hidden",
 	"--", "-all", "-backwards", "-count", "-elide", "-exact", "-forwards",
-	"-hidden", "-nocase", "-nolinestop", "-overlap", "-regexp",
-	"-strictlimits", NULL
+	"-nocase", "-nolinestop", "-overlap", "-regexp", "-strictlimits", NULL
     };
     enum SearchSwitches {
+	SEARCH_HIDDEN,
 	SEARCH_END, SEARCH_ALL, SEARCH_BACK, SEARCH_COUNT, SEARCH_ELIDE,
-	SEARCH_EXACT, SEARCH_FWD, SEARCH_HIDDEN, SEARCH_NOCASE,
+	SEARCH_EXACT, SEARCH_FWD, SEARCH_NOCASE,
 	SEARCH_NOLINESTOP, SEARCH_OVERLAP, SEARCH_REGEXP, SEARCH_STRICTLIMITS
     };
 
@@ -3696,21 +3708,20 @@ TextSearchCmd(
 
     for (i=2 ; i<objc ; i++) {
 	int index;
+
 	if (Tcl_GetString(objv[i])[0] != '-') {
 	    break;
 	}
 
-	if (Tcl_GetIndexFromObj(interp, objv[i], switchStrings, "switch", 0,
+	if (Tcl_GetIndexFromObj(NULL, objv[i], switchStrings, "switch", 0,
 		&index) != TCL_OK) {
 	    /*
-	     * Hide the -hidden option.
+	     * Hide the -hidden option, generating the error description with
+	     * the side effects of T_GIFO.
 	     */
 
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "bad switch \"", Tcl_GetString(objv[i]),
-		    "\": must be --, -all, -backward, -count, -elide, ",
-		    "-exact, -forward, -nocase, -nolinestop, -overlap, ",
-		    "-regexp, or -strictlimits", NULL);
+	    (void) Tcl_GetIndexFromObj(interp, objv[i], switchStrings+1,
+		    "switch", 0, &index);
 	    return TCL_ERROR;
 	}
 
@@ -3726,8 +3737,9 @@ TextSearchCmd(
 	    break;
 	case SEARCH_COUNT:
 	    if (i >= objc-1) {
-		Tcl_SetResult(interp, "no value given for \"-count\" option",
-			TCL_STATIC);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"no value given for \"-count\" option", -1));
+		Tcl_SetErrorCode(interp, "TK", "TEXT", "VALUE", NULL);
 		return TCL_ERROR;
 	    }
 	    i++;
@@ -3778,14 +3790,18 @@ TextSearchCmd(
     }
 
     if (searchSpec.noLineStop && searchSpec.exact) {
-	Tcl_SetResult(interp, "the \"-nolinestop\" option requires the "
-		"\"-regexp\" option to be present", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"the \"-nolinestop\" option requires the \"-regexp\" option"
+		" to be present", -1));
+	Tcl_SetErrorCode(interp, "TK", "TEXT", "SEARCH_USAGE", NULL);
 	return TCL_ERROR;
     }
 
     if (searchSpec.overlap && !searchSpec.all) {
-	Tcl_SetResult(interp, "the \"-overlap\" option requires the "
-		"\"-all\" option to be present", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"the \"-overlap\" option requires the \"-all\" option"
+		" to be present", -1));
+	Tcl_SetErrorCode(interp, "TK", "TEXT", "SEARCH_USAGE", NULL);
 	return TCL_ERROR;
     }
 
@@ -4402,8 +4418,10 @@ TkTextGetTabs(
 	}
 
 	if (tabPtr->location <= 0) {
-	    Tcl_AppendResult(interp, "tab stop \"", Tcl_GetString(objv[i]),
-		    "\" is not at a positive distance", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "tab stop \"%s\" is not at a positive distance",
+		    Tcl_GetString(objv[i])));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "TAB_STOP", NULL);
 	    goto error;
 	}
 
@@ -4433,11 +4451,11 @@ TkTextGetTabs(
 	    }
 	    lastStop = tabPtr->location;
 #else
-	    Tcl_AppendResult(interp,
-		    "tabs must be monotonically increasing, but \"",
-		    Tcl_GetString(objv[i]),
-		    "\" is smaller than or equal to the previous tab",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "tabs must be monotonically increasing, but \"%s\" is "
+		    "smaller than or equal to the previous tab",
+		    Tcl_GetString(objv[i])));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "TAB_STOP", NULL);
 	    goto error;
 #endif /* _TK_ALLOW_DECREASING_TABS */
 	}
@@ -4568,10 +4586,7 @@ TextDumpCmd(
 	case DUMP_CMD:
 	    arg++;
 	    if (arg >= objc) {
-		Tcl_AppendResult(interp, "Usage: ", Tcl_GetString(objv[0]),
-			" dump ?-all -image -text -mark -tag -window? ",
-			"?-command script? index ?index2?", NULL);
-		return TCL_ERROR;
+		goto wrongArgs;
 	    }
 	    command = objv[arg];
 	    break;
@@ -4580,9 +4595,11 @@ TextDumpCmd(
 	}
     }
     if (arg >= objc || arg+2 < objc) {
-	Tcl_AppendResult(interp, "Usage: ", Tcl_GetString(objv[0]),
-		" dump ?-all -image -text -mark -tag -window? ",
-		"?-command script? index ?index2?", NULL);
+    wrongArgs:
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Usage: %s dump ?-all -image -text -mark -tag -window? "
+		"?-command script? index ?index2?", Tcl_GetString(objv[0])));
+	Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	return TCL_ERROR;
     }
     if (what == 0) {
@@ -4603,7 +4620,7 @@ TextDumpCmd(
 	    return TCL_ERROR;
 	}
 	str = Tcl_GetStringFromObj(objv[arg], &length);
-	if (strncmp(str, "end", (unsigned)length) == 0) {
+	if (strncmp(str, "end", (unsigned) length) == 0) {
 	    atEnd = 1;
 	}
     }
@@ -4748,8 +4765,7 @@ DumpLine(
 		int length = last - first;
 		char *range = ckalloc(length + 1);
 
-		memcpy(range, segPtr->body.chars + first,
-			length * sizeof(char));
+		memcpy(range, segPtr->body.chars + first, length);
 		range[length] = '\0';
 
 		TkTextMakeByteIndex(textPtr->sharedTextPtr->tree, textPtr,
@@ -4826,6 +4842,7 @@ DumpLine(
 			command, &index, what);
 	    }
 	}
+
 	offset += currentSize;
 	if (lineChanged) {
 	    TkTextSegment *newSegPtr;
@@ -4843,9 +4860,7 @@ DumpLine(
 	    linePtr = TkBTreeFindLine(textPtr->sharedTextPtr->tree,
 		    textPtr, lineno);
 	    newSegPtr = linePtr->segPtr;
-	    if (segPtr == newSegPtr) {
-		segPtr = segPtr->nextPtr;
-	    } else {
+	    if (segPtr != newSegPtr) {
 		while ((newOffset < endByte) && (newOffset < offset)
 			&& (newSegPtr != NULL)) {
 		    newOffset += currentSize;
@@ -4867,11 +4882,9 @@ DumpLine(
 		    }
 		}
 		segPtr = newSegPtr;
-		if (segPtr != NULL) {
-		    segPtr = segPtr->nextPtr;
-		}
 	    }
-	} else {
+	}
+	if (segPtr != NULL) {
 	    segPtr = segPtr->nextPtr;
 	}
     }
@@ -4910,31 +4923,25 @@ DumpSegment(
     int what)			/* Look for TK_DUMP_INDEX bit. */
 {
     char buffer[TK_POS_CHARS];
+    Tcl_Obj *values[3], *tuple;
 
     TkTextPrintIndex(textPtr, index, buffer);
+    values[0] = Tcl_NewStringObj(key, -1);
+    values[1] = Tcl_NewStringObj(value, -1);
+    values[2] = Tcl_NewStringObj(buffer, -1);
+    tuple = Tcl_NewListObj(3, values);
     if (command == NULL) {
-	Tcl_AppendElement(interp, key);
-	Tcl_AppendElement(interp, value);
-	Tcl_AppendElement(interp, buffer);
+	Tcl_ListObjAppendList(NULL, Tcl_GetObjResult(interp), tuple);
+	Tcl_DecrRefCount(tuple);
 	return 0;
     } else {
-	const char *argv[4];
-	char *list;
 	int oldStateEpoch = TkBTreeEpoch(textPtr->sharedTextPtr->tree);
 
-	argv[0] = key;
-	argv[1] = value;
-	argv[2] = buffer;
-	argv[3] = NULL;
-	list = Tcl_Merge(3, argv);
-	Tcl_VarEval(interp, Tcl_GetString(command), " ", list, NULL);
-	ckfree(list);
-	if ((textPtr->flags & DESTROYED) ||
-		TkBTreeEpoch(textPtr->sharedTextPtr->tree) != oldStateEpoch) {
-	    return 1;
-	} else {
-	    return 0;
-	}
+	Tcl_VarEval(interp, Tcl_GetString(command), " ", Tcl_GetString(tuple),
+		NULL);
+	Tcl_DecrRefCount(tuple);
+	return ((textPtr->flags & DESTROYED) ||
+		TkBTreeEpoch(textPtr->sharedTextPtr->tree) != oldStateEpoch);
     }
 }
 
@@ -5057,8 +5064,7 @@ TextEditCmd(
     int objc,			/* Number of arguments. */
     Tcl_Obj *const objv[])	/* Argument objects. */
 {
-    int index;
-
+    int index, setModified, oldModified;
     static const char *const editOptionStrings[] = {
 	"modified", "redo", "reset", "separator", "undo", NULL
     };
@@ -5081,39 +5087,36 @@ TextEditCmd(
 	if (objc == 3) {
 	    Tcl_SetObjResult(interp,
 		    Tcl_NewBooleanObj(textPtr->sharedTextPtr->isDirty));
+	    return TCL_OK;
 	} else if (objc != 4) {
 	    Tcl_WrongNumArgs(interp, 3, objv, "?boolean?");
 	    return TCL_ERROR;
-	} else {
-	    int setModified, oldModified;
-
-	    if (Tcl_GetBooleanFromObj(interp, objv[3],
-		    &setModified) != TCL_OK) {
-		return TCL_ERROR;
-	    }
+	} else if (Tcl_GetBooleanFromObj(interp, objv[3],
+		&setModified) != TCL_OK) {
+	    return TCL_ERROR;
+	}
 
-	    /*
-	     * Set or reset the dirty info, and trigger a Modified event.
-	     */
+	/*
+	 * Set or reset the dirty info, and trigger a Modified event.
+	 */
 
-	    setModified = setModified ? 1 : 0;
+	setModified = setModified ? 1 : 0;
 
-	    oldModified = textPtr->sharedTextPtr->isDirty;
-	    textPtr->sharedTextPtr->isDirty = setModified;
-	    if (setModified) {
-		textPtr->sharedTextPtr->dirtyMode = TK_TEXT_DIRTY_FIXED;
-	    } else {
-		textPtr->sharedTextPtr->dirtyMode = TK_TEXT_DIRTY_NORMAL;
-	    }
+	oldModified = textPtr->sharedTextPtr->isDirty;
+	textPtr->sharedTextPtr->isDirty = setModified;
+	if (setModified) {
+	    textPtr->sharedTextPtr->dirtyMode = TK_TEXT_DIRTY_FIXED;
+	} else {
+	    textPtr->sharedTextPtr->dirtyMode = TK_TEXT_DIRTY_NORMAL;
+	}
 
-	    /*
-	     * Only issue the <<Modified>> event if the flag actually changed.
-	     * However, degree of modified-ness doesn't matter. [Bug 1799782]
-	     */
+	/*
+	 * Only issue the <<Modified>> event if the flag actually changed.
+	 * However, degree of modified-ness doesn't matter. [Bug 1799782]
+	 */
 
-	    if ((!oldModified) != (!setModified)) {
-		GenerateModifiedEvent(textPtr);
-	    }
+	if ((!oldModified) != (!setModified)) {
+	    GenerateModifiedEvent(textPtr);
 	}
 	break;
     case EDIT_REDO:
@@ -5122,7 +5125,8 @@ TextEditCmd(
 	    return TCL_ERROR;
 	}
 	if (TextEditRedo(textPtr)) {
-	    Tcl_AppendResult(interp, "nothing to redo", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj("nothing to redo", -1));
+	    Tcl_SetErrorCode(interp, "TK", "TEXT", "NO_REDO", NULL);
 	    return TCL_ERROR;
 	}
 	break;
@@ -5146,7 +5150,8 @@ TextEditCmd(
 	    return TCL_ERROR;
 	}
 	if (TextEditUndo(textPtr)) {
-	    Tcl_AppendResult(interp, "nothing to undo", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj("nothing to undo", -1));
+	    Tcl_SetErrorCode(interp, "TK", "TEXT", "NO_UNDO", NULL);
 	    return TCL_ERROR;
 	}
 	break;
@@ -5206,11 +5211,10 @@ TextGetText(
 
     if (TkTextIndexCmp(indexPtr1, indexPtr2) < 0) {
 	while (1) {
-	    int offset, last;
-	    TkTextSegment *segPtr;
+	    int offset;
+	    TkTextSegment *segPtr = TkTextIndexToSeg(&tmpIndex, &offset);
+	    int last = segPtr->size, last2;
 
-	    segPtr = TkTextIndexToSeg(&tmpIndex, &offset);
-	    last = segPtr->size;
 	    if (tmpIndex.linePtr == indexPtr2->linePtr) {
 		/*
 		 * The last line that was requested must be handled carefully,
@@ -5220,21 +5224,17 @@ TextGetText(
 
 		if (indexPtr2->byteIndex == tmpIndex.byteIndex) {
 		    break;
-		} else {
-		    int last2 = indexPtr2->byteIndex - tmpIndex.byteIndex
-			    + offset;
-
-		    if (last2 < last) {
-			last = last2;
-		    }
 		}
-	    }
-	    if (segPtr->typePtr == &tkTextCharType) {
-		if (!visibleOnly || !TkTextIsElided(textPtr,&tmpIndex,NULL)) {
-		    Tcl_AppendToObj(resultPtr, segPtr->body.chars + offset,
-			    last - offset);
+		last2 = indexPtr2->byteIndex - tmpIndex.byteIndex + offset;
+		if (last2 < last) {
+		    last = last2;
 		}
 	    }
+	    if (segPtr->typePtr == &tkTextCharType &&
+		    !(visibleOnly && TkTextIsElided(textPtr,&tmpIndex,NULL))){
+		Tcl_AppendToObj(resultPtr, segPtr->body.chars + offset,
+			last - offset);
+	    }
 	    TkTextIndexForwBytes(textPtr, &tmpIndex, last-offset, &tmpIndex);
 	}
     }
@@ -5262,7 +5262,10 @@ static void
 GenerateModifiedEvent(
     TkText *textPtr)	/* Information about text widget. */
 {
-    union {XEvent general; XVirtualEvent virtual;} event;
+    union {
+	XEvent general;
+	XVirtualEvent virtual;
+    } event;
 
     Tk_MakeWindowExist(textPtr->tkwin);
 
@@ -5398,14 +5401,9 @@ SearchPerform(
 	 * wrap when given a negative search range).
 	 */
 
-	if (searchSpecPtr->backwards) {
-	    if (TkTextIndexCmp(indexFromPtr, indexToPtr) == -1) {
-		return TCL_OK;
-	    }
-	} else {
-	    if (TkTextIndexCmp(indexFromPtr, indexToPtr) == 1) {
-		return TCL_OK;
-	    }
+	if (TkTextIndexCmp(indexFromPtr, indexToPtr) ==
+		(searchSpecPtr->backwards ? -1 : 1)) {
+	    return TCL_OK;
 	}
 
 	if (searchSpecPtr->lineIndexProc(interp, toPtr, searchSpecPtr,
@@ -5712,7 +5710,7 @@ SearchCore(
 			}
 			while (p >= startOfLine + firstOffset) {
 			    if (p[0] == c && !strncmp(p, pattern,
-				    (unsigned)matchLength)) {
+				    (unsigned) matchLength)) {
 				goto backwardsMatch;
 			    }
 			    p--;
@@ -5741,7 +5739,7 @@ SearchCore(
 		     */
 
 		    p = startOfLine + lastOffset - firstNewLine - 1;
-		    if (strncmp(p, pattern, (unsigned)(firstNewLine + 1))) {
+		    if (strncmp(p, pattern, (unsigned) firstNewLine + 1)) {
 			/*
 			 * No match.
 			 */
@@ -6701,9 +6699,7 @@ TkpTesttextCmd(
 
     TkTextSetMark(textPtr, "insert", &index);
     TkTextPrintIndex(textPtr, &index, buf);
-    sprintf(buf + strlen(buf), " %d", index.byteIndex);
-    Tcl_AppendResult(interp, buf, NULL);
-
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf("%s %d", buf, index.byteIndex));
     return TCL_OK;
 }
 
diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
index 1b41e31..d75f61c 100644
--- a/generic/tkTextDisp.c
+++ b/generic/tkTextDisp.c
@@ -5987,8 +5987,11 @@ TkTextScanCmd(
 	dInfoPtr->scanTotalYScroll = 0;
 	dInfoPtr->scanMarkY = y;
     } else {
-	Tcl_AppendResult(interp, "bad scan option \"", Tcl_GetString(objv[2]),
-		"\": must be mark or dragto", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad scan option \"%s\": must be mark or dragto",
+		Tcl_GetString(objv[2])));
+	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "scan option",
+		Tcl_GetString(objv[2]), NULL);
 	return TCL_ERROR;
     }
     return TCL_OK;
@@ -7299,7 +7302,7 @@ CharChunkMeasureChars(
 
     return MeasureChars(tkfont, chars, charsLen, start, end-start,
 	    startX, maxX, flags, nextXPtr);
-#else
+#else /* TK_LAYOUT_WITH_BASE_CHUNKS */
     {
 	int xDisplacement;
 	int fit, bstart = start, bend = end;
@@ -7339,7 +7342,7 @@ CharChunkMeasureChars(
 	    return fit - bstart;
 	}
     }
-#endif
+#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */
 }
 
 /*
diff --git a/generic/tkTextImage.c b/generic/tkTextImage.c
index 47ee49a..1770cb6 100644
--- a/generic/tkTextImage.c
+++ b/generic/tkTextImage.c
@@ -155,8 +155,10 @@ TkTextImageCmd(
 	}
 	eiPtr = TkTextIndexToSeg(&index, NULL);
 	if (eiPtr->typePtr != &tkTextEmbImageType) {
-	    Tcl_AppendResult(interp, "no embedded image at index \"",
-		    Tcl_GetString(objv[3]), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "no embedded image at index \"%s\"",
+		    Tcl_GetString(objv[3])));
+	    Tcl_SetErrorCode(interp, "TK", "TEXT", "NO_IMAGE", NULL);
 	    return TCL_ERROR;
 	}
 	objPtr = Tk_GetOptionValue(interp, (char *) &eiPtr->body.ei,
@@ -178,14 +180,17 @@ TkTextImageCmd(
 	}
 	eiPtr = TkTextIndexToSeg(&index, NULL);
 	if (eiPtr->typePtr != &tkTextEmbImageType) {
-	    Tcl_AppendResult(interp, "no embedded image at index \"",
-		    Tcl_GetString(objv[3]), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "no embedded image at index \"%s\"",
+		    Tcl_GetString(objv[3])));
+	    Tcl_SetErrorCode(interp, "TK", "TEXT", "NO_IMAGE", NULL);
 	    return TCL_ERROR;
 	}
 	if (objc <= 5) {
 	    Tcl_Obj *objPtr = Tk_GetOptionInfo(interp,
 		    (char *) &eiPtr->body.ei, eiPtr->body.ei.optionTable,
 		    (objc == 5) ? objv[4] : NULL, textPtr->tkwin);
+
 	    if (objPtr == NULL) {
 		return TCL_ERROR;
 	    } else {
@@ -272,16 +277,20 @@ TkTextImageCmd(
     case CMD_NAMES: {
 	Tcl_HashSearch search;
 	Tcl_HashEntry *hPtr;
+	Tcl_Obj *resultObj;
 
 	if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 3, objv, NULL);
 	    return TCL_ERROR;
 	}
+	resultObj = Tcl_NewObj();
 	for (hPtr = Tcl_FirstHashEntry(&textPtr->sharedTextPtr->imageTable,
 		&search); hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
-	    Tcl_AppendElement(interp,
-		    Tcl_GetHashKey(&textPtr->sharedTextPtr->markTable, hPtr));
+	    Tcl_ListObjAppendElement(NULL, resultObj, Tcl_NewStringObj(
+		    Tcl_GetHashKey(&textPtr->sharedTextPtr->markTable, hPtr),
+		    -1));
 	}
+	Tcl_SetObjResult(interp, resultObj);
 	return TCL_OK;
     }
     default:
@@ -323,11 +332,12 @@ EmbImageConfigure(
     Tcl_HashEntry *hPtr;
     Tcl_HashSearch search;
     char *name;
+    int dummy;
     int count = 0;		/* The counter for picking a unique name */
     int conflict = 0;		/* True if we have a name conflict */
-    size_t len;		/* length of image name */
+    size_t len;			/* length of image name */
 
-    if (Tk_SetOptions(textPtr->interp, (char*)&eiPtr->body.ei,
+    if (Tk_SetOptions(textPtr->interp, (char *) &eiPtr->body.ei,
 	    eiPtr->body.ei.optionTable,
 	    objc, objv, textPtr->tkwin, NULL, NULL) != TCL_OK) {
 	return TCL_ERROR;
@@ -369,9 +379,11 @@ EmbImageConfigure(
     	name = eiPtr->body.ei.imageString;
     }
     if (name == NULL) {
-	Tcl_AppendResult(textPtr->interp, "Either a \"-name\" ",
-		"or a \"-image\" argument must be provided ",
-		"to the \"image create\" subcommand.", NULL);
+	Tcl_SetObjResult(textPtr->interp, Tcl_NewStringObj(
+		"Either a \"-name\" or a \"-image\" argument must be"
+		" provided to the \"image create\" subcommand", -1));
+	Tcl_SetErrorCode(textPtr->interp, "TK", "TEXT", "IMAGE_CREATE_USAGE",
+		NULL);
 	return TCL_ERROR;
     }
     len = strlen(name);
@@ -403,14 +415,10 @@ EmbImageConfigure(
 	Tcl_DStringAppend(&newName, buf, -1);
     }
     name = Tcl_DStringValue(&newName);
-    {
-	int dummy;
-
-	hPtr = Tcl_CreateHashEntry(&textPtr->sharedTextPtr->imageTable, name,
-		&dummy);
-    }
+    hPtr = Tcl_CreateHashEntry(&textPtr->sharedTextPtr->imageTable, name,
+	    &dummy);
     Tcl_SetHashValue(hPtr, eiPtr);
-    Tcl_AppendResult(textPtr->interp, name, NULL);
+    Tcl_SetObjResult(textPtr->interp, Tcl_NewStringObj(name, -1));
     eiPtr->body.ei.name = ckalloc(Tcl_DStringLength(&newName) + 1);
     strcpy(eiPtr->body.ei.name, name);
     Tcl_DStringFree(&newName);
diff --git a/generic/tkTextIndex.c b/generic/tkTextIndex.c
index c11ce0b..25888d8 100644
--- a/generic/tkTextIndex.c
+++ b/generic/tkTextIndex.c
@@ -84,6 +84,7 @@ FreeTextIndexInternalRep(
 				 * free. */
 {
     TkTextIndex *indexPtr = GET_TEXTINDEX(indexObjPtr);
+
     if (indexPtr->textPtr != NULL) {
 	if (--indexPtr->textPtr->refCount == 0) {
 	    /*
@@ -133,7 +134,6 @@ UpdateStringOfTextIndex(
 {
     char buffer[TK_POS_CHARS];
     register int len;
-
     const TkTextIndex *indexPtr = GET_TEXTINDEX(objPtr);
 
     len = TkTextPrintIndex(indexPtr->textPtr, indexPtr, buffer);
@@ -148,8 +148,10 @@ SetTextIndexFromAny(
     Tcl_Interp *interp,		/* Used for error reporting if not NULL. */
     Tcl_Obj *objPtr)		/* The object to convert. */
 {
-    Tcl_AppendResult(interp, "can't convert value to textindex except "
-	    "via TkTextGetIndexFromObj API", -1);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+	    "can't convert value to textindex except via"
+	    " TkTextGetIndexFromObj API", -1));
+    Tcl_SetErrorCode(interp, "TK", "API_ABUSE", NULL);
     return TCL_ERROR;
 }
 
@@ -830,15 +832,14 @@ GetIndex(
 	if (!TkBTreeCharTagged(&first, tagPtr) && !TkBTreeNextTag(&search)) {
 	    if (tagPtr == textPtr->selTagPtr) {
 		tagName = "sel";
-	    } else {
-		if (hPtr != NULL) {
-		    tagName = Tcl_GetHashKey(&sharedPtr->tagTable, hPtr);
-		}
+	    } else if (hPtr != NULL) {
+		tagName = Tcl_GetHashKey(&sharedPtr->tagTable, hPtr);
 	    }
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp,
-		    "text doesn't contain any characters tagged with \"",
-		    tagName, "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "text doesn't contain any characters tagged with \"%s\"",
+		    tagName));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "TEXT_INDEX", tagName,
+		    NULL);
 	    Tcl_DStringFree(&copy);
 	    return TCL_ERROR;
 	}
@@ -1001,8 +1002,8 @@ GetIndex(
 
   error:
     Tcl_DStringFree(&copy);
-    Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp, "bad text index \"", string, "\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf("bad text index \"%s\"", string));
+    Tcl_SetErrorCode(interp, "TK", "TEXT", "BAD_INDEX", NULL);
     return TCL_ERROR;
 }
 
diff --git a/generic/tkTextMark.c b/generic/tkTextMark.c
index 76ab1a9..a306a05 100644
--- a/generic/tkTextMark.c
+++ b/generic/tkTextMark.c
@@ -26,6 +26,7 @@
  * Forward references for functions defined in this file:
  */
 
+static Tcl_Obj *	GetMarkName(TkText *textPtr, TkTextSegment *segPtr);
 static void		InsertUndisplayProc(TkText *textPtr,
 			    TkTextDispChunk *chunkPtr);
 static int		MarkDeleteProc(TkTextSegment *segPtr,
@@ -132,7 +133,7 @@ TkTextMarkCmd(
 	    Tcl_WrongNumArgs(interp, 3, objv, "markName ?gravity?");
 	    return TCL_ERROR;
 	}
-	str = Tcl_GetStringFromObj(objv[3],&length);
+	str = Tcl_GetStringFromObj(objv[3], &length);
 	if (length == 6 && !strcmp(str, "insert")) {
 	    markPtr = textPtr->insertMarkPtr;
 	} else if (length == 7 && !strcmp(str, "current")) {
@@ -140,18 +141,23 @@ TkTextMarkCmd(
 	} else {
 	    hPtr = Tcl_FindHashEntry(&textPtr->sharedTextPtr->markTable, str);
 	    if (hPtr == NULL) {
-		Tcl_AppendResult(interp, "there is no mark named \"",
-			Tcl_GetString(objv[3]), "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"there is no mark named \"%s\"", str));
+		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "TEXT_MARK", str,
+			NULL);
 		return TCL_ERROR;
 	    }
 	    markPtr = Tcl_GetHashValue(hPtr);
 	}
 	if (objc == 4) {
+	    const char *typeStr;
+
 	    if (markPtr->typePtr == &tkTextRightMarkType) {
-		Tcl_SetResult(interp, "right", TCL_STATIC);
+		typeStr = "right";
 	    } else {
-		Tcl_SetResult(interp, "left", TCL_STATIC);
+		typeStr = "left";
 	    }
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(typeStr, -1));
 	    return TCL_OK;
 	}
 	str = Tcl_GetStringFromObj(objv[4],&length);
@@ -162,8 +168,9 @@ TkTextMarkCmd(
 		(strncmp(str, "right", (unsigned) length) == 0)) {
 	    newTypePtr = &tkTextRightMarkType;
 	} else {
-	    Tcl_AppendResult(interp, "bad mark gravity \"", str,
-		    "\": must be left or right", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad mark gravity \"%s\": must be left or right", str));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "MARK_GRAVITY", NULL);
 	    return TCL_ERROR;
 	}
 	TkTextMarkSegToIndex(textPtr, markPtr, &index);
@@ -172,19 +179,27 @@ TkTextMarkCmd(
 	TkBTreeLinkSegment(markPtr, &index);
 	break;
     }
-    case MARK_NAMES:
+    case MARK_NAMES: {
+	Tcl_Obj *resultObj;
+
 	if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 3, objv, NULL);
 	    return TCL_ERROR;
 	}
-	Tcl_AppendElement(interp, "insert");
-	Tcl_AppendElement(interp, "current");
+	resultObj = Tcl_NewObj();
+	Tcl_ListObjAppendElement(NULL, resultObj, Tcl_NewStringObj(
+		"insert", -1));
+	Tcl_ListObjAppendElement(NULL, resultObj, Tcl_NewStringObj(
+		"current", -1));
 	for (hPtr = Tcl_FirstHashEntry(&textPtr->sharedTextPtr->markTable,
 		&search); hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
-	    Tcl_AppendElement(interp,
-		    Tcl_GetHashKey(&textPtr->sharedTextPtr->markTable, hPtr));
+	    Tcl_ListObjAppendElement(NULL, resultObj, Tcl_NewStringObj(
+		    Tcl_GetHashKey(&textPtr->sharedTextPtr->markTable, hPtr),
+		    -1));
 	}
+	Tcl_SetObjResult(interp, resultObj);
 	break;
+    }
     case MARK_NEXT:
 	if (objc != 4) {
 	    Tcl_WrongNumArgs(interp, 3, objv, "index");
@@ -843,28 +858,12 @@ MarkFindNext(
 	for ( ; segPtr != NULL ; segPtr = segPtr->nextPtr) {
 	    if (segPtr->typePtr == &tkTextRightMarkType ||
 		    segPtr->typePtr == &tkTextLeftMarkType) {
-		if (segPtr == textPtr->currentMarkPtr) {
-		    Tcl_SetResult(interp, "current", TCL_STATIC);
-		} else if (segPtr == textPtr->insertMarkPtr) {
-		    Tcl_SetResult(interp, "insert", TCL_STATIC);
-		} else if (segPtr->body.mark.hPtr == NULL) {
-		    /*
-		     * Ignore widget-specific marks for the other widgets.
-                     * This is either an insert or a current mark
-                     * (markPtr->body.mark.hPtr actually receives NULL
-                     * for these marks in TkTextSetMark).
-                     * The insert and current marks for textPtr having
-                     * already been tested above, the current segment is
-                     * an insert or current mark from a peer of textPtr,
-                     * which we don't want to return.
-                     */
-		    continue;
-		} else {
-		    Tcl_SetResult(interp,
-			    Tcl_GetHashKey(&textPtr->sharedTextPtr->markTable,
-			    segPtr->body.mark.hPtr), TCL_STATIC);
+		Tcl_Obj *markName = GetMarkName(textPtr, segPtr);
+
+		if (markName != NULL) {
+		    Tcl_SetObjResult(interp, markName);
+		    return TCL_OK;
 		}
-		return TCL_OK;
 	    }
 	}
 	index.linePtr = TkBTreeNextLine(textPtr, index.linePtr);
@@ -962,28 +961,11 @@ MarkFindPrev(
 	    }
 	}
 	if (prevPtr != NULL) {
-	    if (prevPtr == textPtr->currentMarkPtr) {
-		Tcl_SetResult(interp, "current", TCL_STATIC);
-	        return TCL_OK;
-	    } else if (prevPtr == textPtr->insertMarkPtr) {
-		Tcl_SetResult(interp, "insert", TCL_STATIC);
-	        return TCL_OK;
-	    } else if (prevPtr->body.mark.hPtr == NULL) {
-		/*
-		 * Ignore widget-specific marks for the other widgets.
-                 * This is either an insert or a current mark
-                 * (markPtr->body.mark.hPtr actually receives NULL
-                 * for these marks in TkTextSetMark).
-                 * The insert and current marks for textPtr having
-                 * already been tested above, the current segment is
-                 * an insert or current mark from a peer of textPtr,
-                 * which we don't want to return.
-                 */
-	    } else {
-		Tcl_SetResult(interp,
-			Tcl_GetHashKey(&textPtr->sharedTextPtr->markTable,
-			prevPtr->body.mark.hPtr), TCL_STATIC);
-	        return TCL_OK;
+	    Tcl_Obj *markName = GetMarkName(textPtr, prevPtr);
+
+	    if (markName != NULL) {
+		Tcl_SetObjResult(interp, markName);
+		return TCL_OK;
 	    }
 	}
 	index.linePtr = TkBTreePreviousLine(textPtr, index.linePtr);
@@ -995,6 +977,46 @@ MarkFindPrev(
 }
 
 /*
+ * ------------------------------------------------------------------------
+ *
+ * GetMarkName --
+ *	Returns the name of the mark that is the given text segment, or NULL
+ *	if it is unnamed (i.e., a widget-specific mark that isn't "current" or
+ *	"insert").
+ *
+ * ------------------------------------------------------------------------
+ */
+
+static Tcl_Obj *
+GetMarkName(
+    TkText *textPtr,
+    TkTextSegment *segPtr)
+{
+    const char *markName;
+
+    if (segPtr == textPtr->currentMarkPtr) {
+	markName = "current";
+    } else if (segPtr == textPtr->insertMarkPtr) {
+	markName = "insert";
+    } else if (segPtr->body.mark.hPtr == NULL) {
+	/*
+	 * Ignore widget-specific marks for the other widgets. This is either
+	 * an insert or a current mark (markPtr->body.mark.hPtr actually
+	 * receives NULL for these marks in TkTextSetMark). The insert and
+	 * current marks for textPtr having already been tested above, the
+	 * current segment is an insert or current mark from a peer of
+	 * textPtr, which we don't want to return.
+	 */
+
+	return NULL;
+    } else {
+	markName = Tcl_GetHashKey(&textPtr->sharedTextPtr->markTable,
+		segPtr->body.mark.hPtr);
+    }
+    return Tcl_NewStringObj(markName, -1);
+}
+
+/*
  * Local Variables:
  * mode: c
  * c-basic-offset: 4
diff --git a/generic/tkTextTag.c b/generic/tkTextTag.c
index 6cd018a..beb7eb5 100644
--- a/generic/tkTextTag.c
+++ b/generic/tkTextTag.c
@@ -100,7 +100,7 @@ static TkTextTag *	FindTag(Tcl_Interp *interp, TkText *textPtr,
 			    Tcl_Obj *tagName);
 static void		SortTags(int numTags, TkTextTag **tagArrayPtr);
 static int		TagSortProc(const void *first, const void *second);
-static void             TagBindEvent(TkText *textPtr, XEvent *eventPtr,
+static void		TagBindEvent(TkText *textPtr, XEvent *eventPtr,
 			    int numTags, TkTextTag **tagArrayPtr);
 
 /*
@@ -213,7 +213,7 @@ TkTextTagCmd(
 
 		if (tagPtr == textPtr->selTagPtr) {
 		    /*
-		     * Send an event that the selection changed.  This is
+		     * Send an event that the selection changed. This is
 		     * equivalent to:
 		     *	   event generate $textWidget <<Selection>>
 		     */
@@ -276,10 +276,10 @@ TkTextTagCmd(
 		    |KeyReleaseMask|PointerMotionMask|VirtualEventMask)) {
 		Tk_DeleteBinding(interp, textPtr->sharedTextPtr->bindingTable,
 			(ClientData) tagPtr->name, Tcl_GetString(objv[4]));
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "requested illegal events; ",
-			"only key, button, motion, enter, leave, and virtual ",
-			"events may be used", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"requested illegal events; only key, button, motion,"
+			" enter, leave, and virtual events may be used", -1));
+		Tcl_SetErrorCode(interp, "TK", "TEXT", "TAG_BIND_EVENT",NULL);
 		return TCL_ERROR;
 	    }
 	} else if (objc == 5) {
@@ -302,7 +302,7 @@ TkTextTagCmd(
 		}
 		Tcl_ResetResult(interp);
 	    } else {
-		Tcl_SetResult(interp, (char *) command, TCL_STATIC);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(command, -1));
 	    }
 	} else {
 	    Tk_GetAllBindings(interp, textPtr->sharedTextPtr->bindingTable,
@@ -457,11 +457,14 @@ TkTextTagCmd(
 			&tagPtr->elide) != TCL_OK) {
 		    return TCL_ERROR;
 		}
-	        /* Indices are potentially obsolete after changing -elide,
-	         * especially those computed with "display" or "any"
-                 * submodifier, therefore increase the epoch.
-                 */
-	        textPtr->sharedTextPtr->stateEpoch++;
+
+		/*
+		 * Indices are potentially obsolete after changing -elide,
+		 * especially those computed with "display" or "any"
+		 * submodifier, therefore increase the epoch.
+		 */
+
+		textPtr->sharedTextPtr->stateEpoch++;
 	    }
 
 	    /*
@@ -646,6 +649,7 @@ TkTextTagCmd(
 	TkTextIndex last;
 	TkTextSearch tSearch;
 	char position[TK_POS_CHARS];
+	Tcl_Obj *resultObj;
 
 	if ((objc != 5) && (objc != 6)) {
 	    Tcl_WrongNumArgs(interp, 3, objv, "tagName index1 ?index2?");
@@ -714,11 +718,15 @@ TkTextTagCmd(
 	if (TkTextIndexCmp(&tSearch.curIndex, &index2) >= 0) {
 	    return TCL_OK;
 	}
+	resultObj = Tcl_NewObj();
 	TkTextPrintIndex(textPtr, &tSearch.curIndex, position);
-	Tcl_AppendElement(interp, position);
+	Tcl_ListObjAppendElement(NULL, resultObj,
+		Tcl_NewStringObj(position, -1));
 	TkBTreeNextTag(&tSearch);
 	TkTextPrintIndex(textPtr, &tSearch.curIndex, position);
-	Tcl_AppendElement(interp, position);
+	Tcl_ListObjAppendElement(NULL, resultObj,
+		Tcl_NewStringObj(position, -1));
+	Tcl_SetObjResult(interp, resultObj);
 	break;
     }
     case TAG_PREVRANGE: {
@@ -726,6 +734,7 @@ TkTextTagCmd(
 	TkTextSearch tSearch;
 	char position1[TK_POS_CHARS];
 	char position2[TK_POS_CHARS];
+	Tcl_Obj *resultObj;
 
 	if ((objc != 5) && (objc != 6)) {
 	    Tcl_WrongNumArgs(interp, 3, objv, "tagName index1 ?index2?");
@@ -773,8 +782,7 @@ TkTextTagCmd(
 
 		TkTextPrintIndex(textPtr, &index2, position1);
 		TkTextPrintIndex(textPtr, &index1, position2);
-		Tcl_AppendElement(interp, position1);
-		Tcl_AppendElement(interp, position2);
+		goto gotPrevIndexPair;
 	    }
 	    return TCL_OK;
 	}
@@ -824,8 +832,14 @@ TkTextTagCmd(
 		}
 	    }
 	}
-	Tcl_AppendElement(interp, position1);
-	Tcl_AppendElement(interp, position2);
+
+    gotPrevIndexPair:
+	resultObj = Tcl_NewObj();
+	Tcl_ListObjAppendElement(NULL, resultObj,
+		Tcl_NewStringObj(position1, -1));
+	Tcl_ListObjAppendElement(NULL, resultObj,
+		Tcl_NewStringObj(position2, -1));
+	Tcl_SetObjResult(interp, resultObj);
 	break;
     }
     case TAG_RAISE: {
@@ -884,12 +898,12 @@ TkTextTagCmd(
 		0, &last);
 	TkBTreeStartSearch(&first, &last, tagPtr, &tSearch);
 	if (TkBTreeCharTagged(&first, tagPtr)) {
-	    Tcl_ListObjAppendElement(interp, listObj,
+	    Tcl_ListObjAppendElement(NULL, listObj,
 		    TkTextNewIndexObj(textPtr, &first));
 	    count++;
 	}
 	while (TkBTreeNextTag(&tSearch)) {
-	    Tcl_ListObjAppendElement(interp, listObj,
+	    Tcl_ListObjAppendElement(NULL, listObj,
 		    TkTextNewIndexObj(textPtr, &tSearch.curIndex));
 	    count++;
 	}
@@ -900,7 +914,7 @@ TkTextTagCmd(
 	     * closed. In this case we add the end of the range.
 	     */
 
-	    Tcl_ListObjAppendElement(interp, listObj,
+	    Tcl_ListObjAppendElement(NULL, listObj,
 		    TkTextNewIndexObj(textPtr, &last));
 	}
 	Tcl_SetObjResult(interp, listObj);
@@ -941,15 +955,15 @@ TkTextCreateTag(
     const char *name;
 
     if (!strcmp(tagName, "sel")) {
-        if (textPtr->selTagPtr != NULL) {
+	if (textPtr->selTagPtr != NULL) {
 	    if (newTag != NULL) {
-	        *newTag = 0;
+		*newTag = 0;
 	    }
-            return textPtr->selTagPtr;
-        }
+	    return textPtr->selTagPtr;
+	}
 	if (newTag != NULL) {
 	    *newTag = 1;
-        }
+	}
 	name = "sel";
     } else {
 	hPtr = Tcl_CreateHashEntry(&textPtr->sharedTextPtr->tagTable,
@@ -1048,15 +1062,15 @@ FindTag(
 				 * NULL, then don't record an error
 				 * message. */
     TkText *textPtr,		/* Widget in which tag is being used. */
-    Tcl_Obj *tagName)	        /* Name of desired tag. */
+    Tcl_Obj *tagName)		/* Name of desired tag. */
 {
     Tcl_HashEntry *hPtr;
     int len;
     const char *str;
 
     str = Tcl_GetStringFromObj(tagName, &len);
-    if (len == 3 && !strcmp(str,"sel")) {
-        return textPtr->selTagPtr;
+    if (len == 3 && !strcmp(str, "sel")) {
+	return textPtr->selTagPtr;
     }
     hPtr = Tcl_FindHashEntry(&textPtr->sharedTextPtr->tagTable,
 	    Tcl_GetString(tagName));
@@ -1064,8 +1078,11 @@ FindTag(
 	return Tcl_GetHashValue(hPtr);
     }
     if (interp != NULL) {
-	Tcl_AppendResult(interp, "tag \"", Tcl_GetString(tagName),
-		"\" isn't defined in text widget", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"tag \"%s\" isn't defined in text widget",
+		Tcl_GetString(tagName)));
+	Tcl_SetErrorCode(interp, "TK", "LOOKUP", "TEXT_TAG",
+		Tcl_GetString(tagName), NULL);
     }
     return NULL;
 }
@@ -1385,7 +1402,7 @@ TkTextBindProc(
     XEvent *eventPtr)		/* Pointer to X event that just happened. */
 {
     TkText *textPtr = clientData;
-    int repick  = 0;
+    int repick = 0;
 
 # define AnyButtonMask \
 	(Button1Mask|Button2Mask|Button3Mask|Button4Mask|Button5Mask)
@@ -1429,7 +1446,7 @@ TkTextBindProc(
 	}
     } else if ((eventPtr->type == EnterNotify)
 	    || (eventPtr->type == LeaveNotify)) {
-	if (eventPtr->xcrossing.state & AnyButtonMask)  {
+	if (eventPtr->xcrossing.state & AnyButtonMask) {
 	    textPtr->flags |= BUTTON_DOWN;
 	} else {
 	    textPtr->flags &= ~BUTTON_DOWN;
@@ -1437,7 +1454,7 @@ TkTextBindProc(
 	TkTextPickCurrent(textPtr, eventPtr);
 	goto done;
     } else if (eventPtr->type == MotionNotify) {
-	if (eventPtr->xmotion.state & AnyButtonMask)  {
+	if (eventPtr->xmotion.state & AnyButtonMask) {
 	    textPtr->flags |= BUTTON_DOWN;
 	} else {
 	    textPtr->flags &= ~BUTTON_DOWN;
@@ -1561,7 +1578,7 @@ TkTextPickCurrent(
 		    = eventPtr->xmotion.same_screen;
 	    textPtr->pickEvent.xcrossing.focus = False;
 	    textPtr->pickEvent.xcrossing.state = eventPtr->xmotion.state;
-	} else  {
+	} else {
 	    textPtr->pickEvent = *eventPtr;
 	}
     }
diff --git a/generic/tkTextWind.c b/generic/tkTextWind.c
index 58d3198..d2998da 100644
--- a/generic/tkTextWind.c
+++ b/generic/tkTextWind.c
@@ -173,8 +173,10 @@ TkTextWindowCmd(
 	}
 	ewPtr = TkTextIndexToSeg(&index, NULL);
 	if (ewPtr->typePtr != &tkTextEmbWindowType) {
-	    Tcl_AppendResult(interp, "no embedded window at index \"",
-		    Tcl_GetString(objv[3]), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "no embedded window at index \"%s\"",
+		    Tcl_GetString(objv[3])));
+	    Tcl_SetErrorCode(interp, "TK", "TEXT", "NO_WINDOW", NULL);
 	    return TCL_ERROR;
 	}
 
@@ -210,8 +212,10 @@ TkTextWindowCmd(
 	}
 	ewPtr = TkTextIndexToSeg(&index, NULL);
 	if (ewPtr->typePtr != &tkTextEmbWindowType) {
-	    Tcl_AppendResult(interp, "no embedded window at index \"",
-		    Tcl_GetString(objv[3]), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "no embedded window at index \"%s\"",
+		    Tcl_GetString(objv[3])));
+	    Tcl_SetErrorCode(interp, "TK", "TEXT", "NO_WINDOW", NULL);
 	    return TCL_ERROR;
 	}
 	if (objc <= 5) {
@@ -331,16 +335,20 @@ TkTextWindowCmd(
     case WIND_NAMES: {
 	Tcl_HashSearch search;
 	Tcl_HashEntry *hPtr;
+	Tcl_Obj *resultObj;
 
 	if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 3, objv, NULL);
 	    return TCL_ERROR;
 	}
+	resultObj = Tcl_NewObj();
 	for (hPtr = Tcl_FirstHashEntry(&textPtr->sharedTextPtr->windowTable,
 		&search); hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
-	    Tcl_AppendElement(interp,
-		    Tcl_GetHashKey(&textPtr->sharedTextPtr->markTable, hPtr));
+	    Tcl_ListObjAppendElement(NULL, resultObj, Tcl_NewStringObj(
+		    Tcl_GetHashKey(&textPtr->sharedTextPtr->markTable, hPtr),
+		    -1));
 	}
+	Tcl_SetObjResult(interp, resultObj);
 	break;
     }
     }
@@ -436,9 +444,12 @@ EmbWinConfigure(
 		}
 		if (Tk_TopWinHierarchy(ancestor)) {
 		badMaster:
-		    Tcl_AppendResult(textPtr->interp, "can't embed ",
-			    Tk_PathName(ewPtr->body.ew.tkwin), " in ",
-			    Tk_PathName(textPtr->tkwin), NULL);
+		    Tcl_SetObjResult(textPtr->interp, Tcl_ObjPrintf(
+			    "can't embed %s in %s",
+			    Tk_PathName(ewPtr->body.ew.tkwin),
+			    Tk_PathName(textPtr->tkwin)));
+		    Tcl_SetErrorCode(textPtr->interp, "TK", "GEOMETRY",
+			    "HIERARCHY", NULL);
 		    ewPtr->body.ew.tkwin = NULL;
 		    if (client != NULL) {
 			client->tkwin = NULL;
@@ -846,7 +857,8 @@ EmbWinLayoutProc(
 	Tk_Window ancestor;
 	Tcl_HashEntry *hPtr;
 	const char *before, *string;
-	Tcl_DString name, buf, *dsPtr = NULL;
+	Tcl_DString buf, *dsPtr = NULL;
+	Tcl_Obj *nameObj;
 
 	before = ewPtr->body.ew.create;
 
@@ -905,36 +917,40 @@ EmbWinLayoutProc(
 	    code = Tcl_GlobalEval(textPtr->interp, ewPtr->body.ew.create);
 	}
 	if (code != TCL_OK) {
-	createError:
 	    Tcl_BackgroundException(textPtr->interp, code);
 	    goto gotWindow;
 	}
-	Tcl_DStringInit(&name);
-	Tcl_DStringAppend(&name, Tcl_GetStringResult(textPtr->interp), -1);
+	nameObj = Tcl_GetObjResult(textPtr->interp);
+	Tcl_IncrRefCount(nameObj);
 	Tcl_ResetResult(textPtr->interp);
 	ewPtr->body.ew.tkwin = Tk_NameToWindow(textPtr->interp,
-		Tcl_DStringValue(&name), textPtr->tkwin);
-	Tcl_DStringFree(&name);
+		Tcl_GetString(nameObj), textPtr->tkwin);
+	Tcl_DecrRefCount(nameObj);
 	if (ewPtr->body.ew.tkwin == NULL) {
-	    goto createError;
+	    Tcl_BackgroundError(textPtr->interp);
+	    goto gotWindow;
 	}
+
 	for (ancestor = textPtr->tkwin; ; ancestor = Tk_Parent(ancestor)) {
 	    if (ancestor == Tk_Parent(ewPtr->body.ew.tkwin)) {
 		break;
 	    }
 	    if (Tk_TopWinHierarchy(ancestor)) {
-	    badMaster:
-		Tcl_AppendResult(textPtr->interp, "can't embed ",
-			Tk_PathName(ewPtr->body.ew.tkwin), " relative to ",
-			Tk_PathName(textPtr->tkwin), NULL);
-		Tcl_BackgroundError(textPtr->interp);
-		ewPtr->body.ew.tkwin = NULL;
-		goto gotWindow;
+		goto badMaster;
 	    }
 	}
 	if (Tk_TopWinHierarchy(ewPtr->body.ew.tkwin)
 		|| (textPtr->tkwin == ewPtr->body.ew.tkwin)) {
-	    goto badMaster;
+	badMaster:
+	    Tcl_SetObjResult(textPtr->interp, Tcl_ObjPrintf(
+		    "can't embed %s relative to %s",
+		    Tk_PathName(ewPtr->body.ew.tkwin),
+		    Tk_PathName(textPtr->tkwin)));
+	    Tcl_SetErrorCode(textPtr->interp, "TK", "GEOMETRY", "HIERARCHY",
+		    NULL);
+	    Tcl_BackgroundError(textPtr->interp);
+	    ewPtr->body.ew.tkwin = NULL;
+	    goto gotWindow;
 	}
 
 	if (client == NULL) {
diff --git a/generic/tkTrig.c b/generic/tkTrig.c
index d999062..a2bf456 100644
--- a/generic/tkTrig.c
+++ b/generic/tkTrig.c
@@ -1375,7 +1375,7 @@ TkMakeBezierPostscript(
     int closed, i;
     int numCoords = numPoints*2;
     double control[8];
-    char buffer[200];
+    Tcl_Obj *psObj;
 
     /*
      * If the curve is a closed one then generate a special spline that spans
@@ -1394,7 +1394,9 @@ TkMakeBezierPostscript(
 	control[5] = 0.833*pointPtr[1] + 0.167*pointPtr[3];
 	control[6] = 0.5*pointPtr[0] + 0.5*pointPtr[2];
 	control[7] = 0.5*pointPtr[1] + 0.5*pointPtr[3];
-	sprintf(buffer, "%.15g %.15g moveto\n%.15g %.15g %.15g %.15g %.15g %.15g curveto\n",
+	psObj = Tcl_ObjPrintf(
+		"%.15g %.15g moveto\n"
+		"%.15g %.15g %.15g %.15g %.15g %.15g curveto\n",
 		control[0], Tk_CanvasPsY(canvas, control[1]),
 		control[2], Tk_CanvasPsY(canvas, control[3]),
 		control[4], Tk_CanvasPsY(canvas, control[5]),
@@ -1403,10 +1405,9 @@ TkMakeBezierPostscript(
 	closed = 0;
 	control[6] = pointPtr[0];
 	control[7] = pointPtr[1];
-	sprintf(buffer, "%.15g %.15g moveto\n",
+	psObj = Tcl_ObjPrintf("%.15g %.15g moveto\n",
 		control[6], Tk_CanvasPsY(canvas, control[7]));
     }
-    Tcl_AppendResult(interp, buffer, NULL);
 
     /*
      * Cycle through all the remaining points in the curve, generating a curve
@@ -1432,12 +1433,15 @@ TkMakeBezierPostscript(
 	control[4] = 0.333*control[6] + 0.667*pointPtr[0];
 	control[5] = 0.333*control[7] + 0.667*pointPtr[1];
 
-	sprintf(buffer, "%.15g %.15g %.15g %.15g %.15g %.15g curveto\n",
+	Tcl_AppendPrintfToObj(psObj,
+		"%.15g %.15g %.15g %.15g %.15g %.15g curveto\n",
 		control[2], Tk_CanvasPsY(canvas, control[3]),
 		control[4], Tk_CanvasPsY(canvas, control[5]),
 		control[6], Tk_CanvasPsY(canvas, control[7]));
-	Tcl_AppendResult(interp, buffer, NULL);
     }
+
+    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    Tcl_DecrRefCount(psObj);
 }
 
 /*
@@ -1472,15 +1476,14 @@ TkMakeRawCurvePostscript(
 {
     int i;
     double *segPtr;
-    char buffer[200];
+    Tcl_Obj *psObj;
 
     /*
      * Put the first point into the path.
      */
 
-    sprintf(buffer, "%.15g %.15g moveto\n",
+    psObj = Tcl_ObjPrintf("%.15g %.15g moveto\n",
 	    pointPtr[0], Tk_CanvasPsY(canvas, pointPtr[1]));
-    Tcl_AppendResult(interp, buffer, NULL);
 
     /*
      * Loop through all the remaining points in the curve, generating a
@@ -1495,19 +1498,19 @@ TkMakeRawCurvePostscript(
 	     * neighbouring knots, so this segment is just a straight line.
 	     */
 
-	    sprintf(buffer, "%.15g %.15g lineto\n",
+	    Tcl_AppendPrintfToObj(psObj, "%.15g %.15g lineto\n",
 		    segPtr[6], Tk_CanvasPsY(canvas, segPtr[7]));
 	} else {
 	    /*
 	     * This is a generic Bezier curve segment.
 	     */
 
-	    sprintf(buffer, "%.15g %.15g %.15g %.15g %.15g %.15g curveto\n",
+	    Tcl_AppendPrintfToObj(psObj,
+		    "%.15g %.15g %.15g %.15g %.15g %.15g curveto\n",
 		    segPtr[2], Tk_CanvasPsY(canvas, segPtr[3]),
 		    segPtr[4], Tk_CanvasPsY(canvas, segPtr[5]),
 		    segPtr[6], Tk_CanvasPsY(canvas, segPtr[7]));
 	}
-	Tcl_AppendResult(interp, buffer, NULL);
     }
 
     /*
@@ -1532,20 +1535,23 @@ TkMakeRawCurvePostscript(
 	     * Straight line.
 	     */
 
-	    sprintf(buffer, "%.15g %.15g lineto\n",
+	    Tcl_AppendPrintfToObj(psObj, "%.15g %.15g lineto\n",
 		    control[6], Tk_CanvasPsY(canvas, control[7]));
 	} else {
 	    /*
 	     * Bezier curve segment.
 	     */
 
-	    sprintf(buffer, "%.15g %.15g %.15g %.15g %.15g %.15g curveto\n",
+	    Tcl_AppendPrintfToObj(psObj,
+		    "%.15g %.15g %.15g %.15g %.15g %.15g curveto\n",
 		    control[2], Tk_CanvasPsY(canvas, control[3]),
 		    control[4], Tk_CanvasPsY(canvas, control[5]),
 		    control[6], Tk_CanvasPsY(canvas, control[7]));
 	}
-	Tcl_AppendResult(interp, buffer, NULL);
     }
+
+    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
+    Tcl_DecrRefCount(psObj);
 }
 
 /*
diff --git a/generic/tkUtil.c b/generic/tkUtil.c
index 5282708..385d1cb 100644
--- a/generic/tkUtil.c
+++ b/generic/tkUtil.c
@@ -56,6 +56,7 @@ TkStateParseProc(
     int c;
     int flags = PTR2INT(clientData);
     size_t length;
+    Tcl_Obj *msgObj;
 
     register Tk_State *statePtr = (Tk_State *) (widgRec + offset);
 
@@ -84,18 +85,20 @@ TkStateParseProc(
 	return TCL_OK;
     }
 
-    Tcl_AppendResult(interp, "bad ", (flags&4)?"-default" : "state",
-	    " value \"", value, "\": must be normal", NULL);
-    if (flags&1) {
-	Tcl_AppendResult(interp, ", active", NULL);
+    msgObj = Tcl_ObjPrintf("bad %s value \"%s\": must be normal",
+	    ((flags & 4) ? "-default" : "state"), value);
+    if (flags & 1) {
+	Tcl_AppendToObj(msgObj, ", active", -1);
     }
-    if (flags&2) {
-	Tcl_AppendResult(interp, ", hidden", NULL);
+    if (flags & 2) {
+	Tcl_AppendToObj(msgObj, ", hidden", -1);
     }
-    if (flags&3) {
-	Tcl_AppendResult(interp, ",", NULL);
+    if (flags & 3) {
+	Tcl_AppendToObj(msgObj, ",", -1);
     }
-    Tcl_AppendResult(interp, " or disabled", NULL);
+    Tcl_AppendToObj(msgObj, " or disabled", -1);
+    Tcl_SetObjResult(interp, msgObj);
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "STATE", NULL);
     *statePtr = TK_STATE_NORMAL;
     return TCL_ERROR;
 }
@@ -195,8 +198,10 @@ TkOrientParseProc(
 	*orientPtr = 1;
 	return TCL_OK;
     }
-    Tcl_AppendResult(interp, "bad orientation \"", value,
-	    "\": must be vertical or horizontal", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad orientation \"%s\": must be vertical or horizontal",
+	    value));
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "ORIENTATION", NULL);
     *orientPtr = 0;
     return TCL_ERROR;
 }
@@ -265,6 +270,7 @@ TkOffsetParseProc(
     Tk_TSOffset tsoffset;
     const char *q, *p;
     int result;
+    Tcl_Obj *msgObj;
 
     if ((value == NULL) || (*value == 0)) {
 	tsoffset.flags = TK_OFFSET_CENTER|TK_OFFSET_MIDDLE;
@@ -376,15 +382,16 @@ TkOffsetParseProc(
     return TCL_OK;
 
   badTSOffset:
-    Tcl_AppendResult(interp, "bad offset \"", value,
-	    "\": expected \"x,y\"", NULL);
+    msgObj = Tcl_ObjPrintf("bad offset \"%s\": expected \"x,y\"", value);
     if (PTR2INT(clientData) & TK_OFFSET_RELATIVE) {
-	Tcl_AppendResult(interp, ", \"#x,y\"", NULL);
+	Tcl_AppendToObj(msgObj, ", \"#x,y\"", -1);
     }
     if (PTR2INT(clientData) & TK_OFFSET_INDEX) {
-	Tcl_AppendResult(interp, ", <index>", NULL);
+	Tcl_AppendToObj(msgObj, ", <index>", -1);
     }
-    Tcl_AppendResult(interp, ", n, ne, e, se, s, sw, w, nw, or center", NULL);
+    Tcl_AppendToObj(msgObj, ", n, ne, e, se, s, sw, w, nw, or center", -1);
+    Tcl_SetObjResult(interp, msgObj);
+    Tcl_SetErrorCode(interp, "TK", "VALUE", "OFFSET", NULL);
     return TCL_ERROR;
 }
 
@@ -481,7 +488,9 @@ TkPixelParseProc(
     result = TkGetDoublePixels(interp, tkwin, value, doublePtr);
 
     if ((result == TCL_OK) && (clientData == NULL) && (*doublePtr < 0.0)) {
-	Tcl_AppendResult(interp, "bad screen distance \"", value, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad screen distance \"%s\"", value));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "PIXELS", NULL);
 	return TCL_ERROR;
     }
     return result;
@@ -644,8 +653,10 @@ Tk_GetScrollInfo(
 
     if ((c == 'm') && (strncmp(argv[2], "moveto", length) == 0)) {
 	if (argc != 4) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
-		    " ", argv[1], " moveto fraction\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # args: should be \"%s %s %s\"",
+		    argv[0], argv[1], "moveto fraction"));
+	    Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	    return TK_SCROLL_ERROR;
 	}
 	if (Tcl_GetDouble(interp, argv[3], dblPtr) != TCL_OK) {
@@ -655,8 +666,10 @@ Tk_GetScrollInfo(
     } else if ((c == 's')
 	    && (strncmp(argv[2], "scroll", length) == 0)) {
 	if (argc != 5) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
-		    " ", argv[1], " scroll number units|pages\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "wrong # args: should be \"%s %s %s\"",
+		    argv[0], argv[1], "scroll number units|pages"));
+	    Tcl_SetErrorCode(interp, "TCL", "WRONGARGS", NULL);
 	    return TK_SCROLL_ERROR;
 	}
 	if (Tcl_GetInt(interp, argv[3], intPtr) != TCL_OK) {
@@ -670,12 +683,15 @@ Tk_GetScrollInfo(
 	    return TK_SCROLL_UNITS;
 	}
 
-	Tcl_AppendResult(interp, "bad argument \"", argv[4],
-		"\": must be units or pages", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad argument \"%s\": must be units or pages", argv[4]));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "SCROLL_UNITS", NULL);
 	return TK_SCROLL_ERROR;
     }
-    Tcl_AppendResult(interp, "unknown option \"", argv[2],
-	    "\": must be moveto or scroll", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "unknown option \"%s\": must be moveto or scroll", argv[2]));
+    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "option", argv[2],
+	    NULL);
     return TK_SCROLL_ERROR;
 }
 
@@ -744,12 +760,14 @@ Tk_GetScrollInfoObj(
 	    return TK_SCROLL_UNITS;
 	}
 
-	Tcl_AppendResult(interp, "bad argument \"", arg,
-		"\": must be units or pages", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad argument \"%s\": must be units or pages", arg));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "SCROLL_UNITS", NULL);
 	return TK_SCROLL_ERROR;
     }
-    Tcl_AppendResult(interp, "unknown option \"", arg,
-	    "\": must be moveto or scroll", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "unknown option \"%s\": must be moveto or scroll", arg));
+    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "option", arg, NULL);
     return TK_SCROLL_ERROR;
 }
 
@@ -913,14 +931,17 @@ TkFindStateNum(
      */
 
     if (interp != NULL) {
+	Tcl_Obj *msgObj;
+
 	mPtr = mapPtr;
-	Tcl_AppendResult(interp, "bad ", option, " value \"", strKey,
-		"\": must be ", mPtr->strKey, NULL);
+	msgObj = Tcl_ObjPrintf("bad %s value \"%s\": must be %s",
+		option, strKey, mPtr->strKey);
 	for (mPtr++; mPtr->strKey != NULL; mPtr++) {
-	    Tcl_AppendResult(interp,
-		    ((mPtr[1].strKey != NULL) ? ", " : ", or "),
-		    mPtr->strKey, NULL);
+	    Tcl_AppendPrintfToObj(msgObj, ",%s %s",
+		    ((mPtr[1].strKey != NULL) ? "" : "or "), mPtr->strKey);
 	}
+	Tcl_SetObjResult(interp, msgObj);
+	Tcl_SetErrorCode(interp, "TK", "LOOKUP", option, strKey, NULL);
     }
     return mPtr->numKey;
 }
@@ -969,14 +990,19 @@ TkFindStateNumObj(
      */
 
     if (interp != NULL) {
+	Tcl_Obj *msgObj;
+
 	mPtr = mapPtr;
-	Tcl_AppendResult(interp, "bad ", Tcl_GetString(optionPtr),
-		" value \"", key, "\": must be ", mPtr->strKey, NULL);
+	msgObj = Tcl_ObjPrintf(
+		"bad %s value \"%s\": must be %s",
+		Tcl_GetString(optionPtr), key, mPtr->strKey);
 	for (mPtr++; mPtr->strKey != NULL; mPtr++) {
-	    Tcl_AppendResult(interp,
-		((mPtr[1].strKey != NULL) ? ", " : ", or "),
-		mPtr->strKey, NULL);
+	    Tcl_AppendPrintfToObj(msgObj, ",%s %s",
+		    ((mPtr[1].strKey != NULL) ? "" : " or"), mPtr->strKey);
 	}
+	Tcl_SetObjResult(interp, msgObj);
+	Tcl_SetErrorCode(interp, "TK", "LOOKUP", Tcl_GetString(optionPtr),
+		key, NULL);
     }
     return mPtr->numKey;
 }
@@ -1007,24 +1033,15 @@ TkBackgroundEvalObjv(
     Tcl_Obj *const *objv,
     int flags)
 {
-    Tcl_DString errorInfo, errorCode;
-    Tcl_SavedResult state;
+    Tcl_InterpState state;
     int n, r = TCL_OK;
 
-    Tcl_DStringInit(&errorInfo);
-    Tcl_DStringInit(&errorCode);
-
-    Tcl_Preserve(interp);
-
     /*
-     * Record the state of the interpreter
+     * Record the state of the interpreter.
      */
 
-    Tcl_SaveResult(interp, &state);
-    Tcl_DStringAppend(&errorInfo,
-	Tcl_GetVar(interp, "errorInfo", TCL_GLOBAL_ONLY), -1);
-    Tcl_DStringAppend(&errorCode,
-	Tcl_GetVar(interp, "errorCode", TCL_GLOBAL_ONLY), -1);
+    Tcl_Preserve(interp);
+    state = Tcl_SaveInterpState(interp, TCL_OK);
 
     /*
      * Evaluate the command and handle any error.
@@ -1042,24 +1059,12 @@ TkBackgroundEvalObjv(
 	Tcl_BackgroundException(interp, r);
     }
 
-    Tcl_Release(interp);
-
-    /*
-     * Restore the state of the interpreter
-     */
-
-    Tcl_SetVar(interp, "errorInfo",
-	Tcl_DStringValue(&errorInfo), TCL_GLOBAL_ONLY);
-    Tcl_SetVar(interp, "errorCode",
-	Tcl_DStringValue(&errorCode), TCL_GLOBAL_ONLY);
-    Tcl_RestoreResult(interp, &state);
-
     /*
-     * Clean up references.
+     * Restore the state of the interpreter.
      */
 
-    Tcl_DStringFree(&errorInfo);
-    Tcl_DStringFree(&errorCode);
+    (void) Tcl_RestoreInterpState(interp, state);
+    Tcl_Release(interp);
 
     return r;
 }
diff --git a/generic/tkVisual.c b/generic/tkVisual.c
index 3602088..8b0c155 100644
--- a/generic/tkVisual.c
+++ b/generic/tkVisual.c
@@ -20,7 +20,7 @@
  */
 
 typedef struct VisualDictionary {
-    const char *name;			/* Textual name of class. */
+    const char *name;		/* Textual name of class. */
     int minLength;		/* Minimum # characters that must be specified
 				 * for an unambiguous match. */
     int class;			/* X symbol for class. */
@@ -173,9 +173,9 @@ Tk_GetVisual(
 	 */
 
 	if (Tcl_GetInt(interp, string, &visualId) == TCL_ERROR) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "bad X identifier for visual: \"",
-		    string, "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad X identifier for visual: \"%s\"", string));
+	    Tcl_SetErrorCode(interp, "TK", "VALUE", "VISUALID", NULL);
 	    return NULL;
 	}
 	template.visualid = visualId;
@@ -202,12 +202,16 @@ Tk_GetVisual(
 	    }
 	}
 	if (template.class == -1) {
-	    Tcl_AppendResult(interp, "unknown or ambiguous visual name \"",
-		    string, "\": class must be ", NULL);
+	    Tcl_Obj *msgObj = Tcl_ObjPrintf(
+		    "unknown or ambiguous visual name \"%s\": class must be ",
+		    string);
+
 	    for (dictPtr = visualNames; dictPtr->name != NULL; dictPtr++) {
-		Tcl_AppendResult(interp, dictPtr->name, ", ", NULL);
+		Tcl_AppendPrintfToObj(msgObj, "%s, ", dictPtr->name);
 	    }
-	    Tcl_AppendResult(interp, "or default", NULL);
+	    Tcl_AppendToObj(msgObj, "or default", -1);
+	    Tcl_SetObjResult(interp, msgObj);
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "VISUAL", string, NULL);
 	    return NULL;
 	}
 	while (isspace(UCHAR(*p))) {
@@ -215,10 +219,8 @@ Tk_GetVisual(
 	}
 	if (*p == 0) {
 	    template.depth = 10000;
-	} else {
-	    if (Tcl_GetInt(interp, p, &template.depth) != TCL_OK) {
-		return NULL;
-	    }
+	} else if (Tcl_GetInt(interp, p, &template.depth) != TCL_OK) {
+	    return NULL;
 	}
 	if (c == 'b') {
 	    mask = 0;
@@ -237,8 +239,9 @@ Tk_GetVisual(
     visInfoList = XGetVisualInfo(Tk_Display(tkwin), mask, &template,
 	    &numVisuals);
     if (visInfoList == NULL) {
-	Tcl_SetResult(interp, "couldn't find an appropriate visual",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"couldn't find an appropriate visual", -1));
+	Tcl_SetErrorCode(interp, "TK", "VISUAL", "INAPPROPRIATE", NULL);
 	return NULL;
     }
 
@@ -403,13 +406,15 @@ Tk_GetColormap(
 	return None;
     }
     if (Tk_Screen(other) != Tk_Screen(tkwin)) {
-	Tcl_AppendResult(interp, "can't use colormap for ", string,
-		": not on same screen", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't use colormap for %s: not on same screen", string));
+	Tcl_SetErrorCode(interp, "TK", "COLORMAP", "SCREEN", NULL);
 	return None;
     }
     if (Tk_Visual(other) != Tk_Visual(tkwin)) {
-	Tcl_AppendResult(interp, "can't use colormap for ", string,
-		": incompatible visuals", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't use colormap for %s: incompatible visuals", string));
+	Tcl_SetErrorCode(interp, "TK", "COLORMAP", "INCOMPATIBLE", NULL);
 	return None;
     }
     colormap = Tk_Colormap(other);
diff --git a/generic/tkWindow.c b/generic/tkWindow.c
index b04b95f..f4138b2 100644
--- a/generic/tkWindow.c
+++ b/generic/tkWindow.c
@@ -103,8 +103,9 @@ static const XSetWindowAttributes defAtts= {
 
 typedef int (TkInitProc)(Tcl_Interp *interp, ClientData clientData);
 typedef struct {
-    const char *name;			/* Name of command. */
-    Tcl_ObjCmdProc *objProc;	/* Command's object- (or string-) based function, or initProc. */
+    const char *name;		/* Name of command. */
+    Tcl_ObjCmdProc *objProc;	/* Command's object- (or string-) based
+				 * function, or initProc. */
     int flags;
 } TkCmd;
 
@@ -153,7 +154,8 @@ static const TkCmd commands[] = {
     {"panedwindow",	Tk_PanedWindowObjCmd,	ISSAFE},
     {"radiobutton",	Tk_RadiobuttonObjCmd,	ISSAFE},
     {"scale",		Tk_ScaleObjCmd,		ISSAFE},
-    {"scrollbar",	(Tcl_ObjCmdProc *) Tk_ScrollbarCmd,	NOOBJPROC|PASSMAINWINDOW|ISSAFE},
+    {"scrollbar",	(Tcl_ObjCmdProc *) Tk_ScrollbarCmd,
+					NOOBJPROC|PASSMAINWINDOW|ISSAFE},
     {"spinbox",		Tk_SpinboxObjCmd,	ISSAFE},
     {"text",		Tk_TextObjCmd,		PASSMAINWINDOW|ISSAFE},
     {"toplevel",	Tk_ToplevelObjCmd,	0},
@@ -175,7 +177,8 @@ static const TkCmd commands[] = {
     {"::tk::panedwindow",Tk_PanedWindowObjCmd,	ISSAFE},
     {"::tk::radiobutton",Tk_RadiobuttonObjCmd,	ISSAFE},
     {"::tk::scale",	Tk_ScaleObjCmd,		ISSAFE},
-    {"::tk::scrollbar",	(Tcl_ObjCmdProc *) Tk_ScrollbarCmd,			NOOBJPROC|PASSMAINWINDOW|ISSAFE},
+    {"::tk::scrollbar",	(Tcl_ObjCmdProc *) Tk_ScrollbarCmd,
+					NOOBJPROC|PASSMAINWINDOW|ISSAFE},
     {"::tk::spinbox",	Tk_SpinboxObjCmd,	ISSAFE},
     {"::tk::text",	Tk_TextObjCmd,		PASSMAINWINDOW|ISSAFE},
     {"::tk::toplevel",	Tk_ToplevelObjCmd,	0},
@@ -197,7 +200,7 @@ static const TkCmd commands[] = {
      * Misc.
      */
 
-#if defined(MAC_OSX_TK)
+#ifdef MAC_OSX_TK
     {"::tk::unsupported::MacWindowStyle",
 			TkUnsupported1ObjCmd,	PASSMAINWINDOW|ISSAFE},
 #endif
@@ -290,6 +293,7 @@ TkCloseDisplay(
 
     if (dispPtr->errorPtr != NULL) {
 	TkErrorHandler *errorPtr;
+
 	for (errorPtr = dispPtr->errorPtr;
 		errorPtr != NULL;
 		errorPtr = dispPtr->errorPtr) {
@@ -383,7 +387,7 @@ CreateTopLevelWindow(
     } else {
 	dispPtr = GetScreen(interp, screenName, &screenId);
 	if (dispPtr == NULL) {
-	    return (Tk_Window) NULL;
+	    return NULL;
 	}
     }
 
@@ -416,7 +420,7 @@ CreateTopLevelWindow(
     if (parent != NULL) {
 	if (NameWindow(interp, winPtr, (TkWindow *) parent, name) != TCL_OK) {
 	    Tk_DestroyWindow((Tk_Window) winPtr);
-	    return (Tk_Window) NULL;
+	    return NULL;
 	}
     }
     TkWmNewWindow(winPtr);
@@ -467,9 +471,9 @@ GetScreen(
 
     screenName = TkGetDefaultScreenName(interp, screenName);
     if (screenName == NULL) {
-	Tcl_SetResult(interp,
-		"no display name and no $DISPLAY environment variable",
-		TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"no display name and no $DISPLAY environment variable", -1));
+	Tcl_SetErrorCode(interp, "TK", "NO_DISPLAY", NULL);
 	return NULL;
     }
     length = strlen(screenName);
@@ -497,9 +501,9 @@ GetScreen(
 
 	    dispPtr = TkpOpenDisplay(screenName);
 	    if (dispPtr == NULL) {
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "couldn't connect to display \"",
-			screenName, "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"couldn't connect to display \"%s\"", screenName));
+		Tcl_SetErrorCode(interp, "TK", "DISPLAY", "CONNECT", NULL);
 		return NULL;
 	    }
 	    dispPtr->nextPtr = tsdPtr->displayList; /* TkGetDisplayList(); */
@@ -531,10 +535,9 @@ GetScreen(
 	}
     }
     if (screenId >= ScreenCount(dispPtr->display)) {
-	char buf[32 + TCL_INTEGER_SPACE];
-
-	sprintf(buf, "bad screen number \"%d\"", screenId);
-	Tcl_SetResult(interp, buf, TCL_VOLATILE);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad screen number \"%d\"", screenId));
+	Tcl_SetErrorCode(interp, "TK", "DISPLAY", "SCREEN_NUMBER", NULL);
 	return NULL;
     }
     *screenPtr = screenId;
@@ -774,24 +777,25 @@ NameWindow(
     }
 
     /*
-     * For non-anonymous windows, set up the window name.
-     */
-
-    winPtr->nameUid = Tk_GetUid(name);
-
-    /*
      * Don't permit names that start with an upper-case letter: this will just
      * cause confusion with class names in the option database.
      */
 
     if (isupper(UCHAR(name[0]))) {
-	Tcl_AppendResult(interp,
-		"window name starts with an upper-case letter: \"",
-		name, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"window name starts with an upper-case letter: \"%s\"",
+		name));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "WINDOW", "NOTCLASS", NULL);
 	return TCL_ERROR;
     }
 
     /*
+     * For non-anonymous windows, set up the window name.
+     */
+
+    winPtr->nameUid = Tk_GetUid(name);
+
+    /*
      * To permit names of arbitrary length, must be prepared to malloc a
      * buffer to hold the new path name. To run fast in the common case where
      * names are short, use a fixed-size buffer on the stack.
@@ -799,7 +803,7 @@ NameWindow(
 
     length1 = strlen(parentPtr->pathName);
     length2 = strlen(name);
-    if ((length1+length2+2) <= FIXED_SIZE) {
+    if ((length1 + length2 + 2) <= FIXED_SIZE) {
 	pathName = staticSpace;
     } else {
 	pathName = ckalloc(length1 + length2 + 2);
@@ -818,8 +822,9 @@ NameWindow(
 	ckfree(pathName);
     }
     if (!isNew) {
-	Tcl_AppendResult(interp, "window name \"", name,
-		"\" already exists in parent", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"window name \"%s\" already exists in parent", name));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "WINDOW", "EXISTS", NULL);
 	return TCL_ERROR;
     }
     Tcl_SetHashValue(hPtr, winPtr);
@@ -856,7 +861,7 @@ TkCreateMainWindow(
     const char *screenName,	/* Name of screen on which to create window.
 				 * Empty or NULL string means use DISPLAY
 				 * environment variable. */
-    const char *baseName)		/* Base name for application; usually of the
+    const char *baseName)	/* Base name for application; usually of the
 				 * form "prog instance". */
 {
     Tk_Window tkwin;
@@ -949,22 +954,27 @@ TkCreateMainWindow(
 
     isSafe = Tcl_IsSafe(interp);
     for (cmdPtr = commands; cmdPtr->name != NULL; cmdPtr++) {
-	if ((cmdPtr->objProc == NULL)) {
+	if (cmdPtr->objProc == NULL) {
 	    Tcl_Panic("TkCreateMainWindow: builtin command with NULL string and object procs");
 	}
+
 #if defined(__WIN32__) && !defined(STATIC_BUILD)
 	if ((cmdPtr->flags & WINMACONLY) && tclStubsPtr->reserved9) {
-	    /* We are running on Cygwin, so don't use the win32 dialogs */
+	    /*
+	     * We are running on Cygwin, so don't use the win32 dialogs.
+	     */
+
 	    continue;
 	}
-#endif
+#endif /* __WIN32__ && !STATIC_BUILD */
+
 	if (cmdPtr->flags & PASSMAINWINDOW) {
 	    clientData = tkwin;
 	} else {
 	    clientData = NULL;
 	}
 	if (cmdPtr->flags & USEINITPROC) {
-	    ((TkInitProc *)cmdPtr->objProc)(interp, clientData);
+	    ((TkInitProc *) cmdPtr->objProc)(interp, clientData);
 	} else if (cmdPtr->flags & NOOBJPROC) {
 	    Tcl_CreateCommand(interp, cmdPtr->name,
 		    (Tcl_CmdProc *) cmdPtr->objProc, clientData, NULL);
@@ -972,10 +982,8 @@ TkCreateMainWindow(
 	    Tcl_CreateObjCommand(interp, cmdPtr->name, cmdPtr->objProc,
 		    clientData, NULL);
 	}
-	if (isSafe) {
-	    if (!(cmdPtr->flags & ISSAFE)) {
-		Tcl_HideCommand(interp, cmdPtr->name, cmdPtr->name);
-	    }
+	if (isSafe && !(cmdPtr->flags & ISSAFE)) {
+	    Tcl_HideCommand(interp, cmdPtr->name, cmdPtr->name);
 	}
     }
 
@@ -1032,13 +1040,15 @@ Tk_CreateWindow(
 
     if (parentPtr) {
 	if (parentPtr->flags & TK_ALREADY_DEAD) {
-	    Tcl_AppendResult(interp,
-		    "can't create window: parent has been destroyed", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't create window: parent has been destroyed", -1));
+	    Tcl_SetErrorCode(interp, "TK", "CREATE", "DEAD_PARENT", NULL);
 	    return NULL;
 	} else if (parentPtr->flags & TK_CONTAINER) {
-	    Tcl_AppendResult(interp,
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		    "can't create window: its parent has -container = yes",
-		    NULL);
+		    -1));
+	    Tcl_SetErrorCode(interp, "TK", "CREATE", "CONTAINER", NULL);
 	    return NULL;
 	} else if (screenName == NULL) {
 	    TkWindow *winPtr = TkAllocWindow(parentPtr->dispPtr,
@@ -1094,13 +1104,15 @@ Tk_CreateAnonymousWindow(
 
     if (parentPtr) {
 	if (parentPtr->flags & TK_ALREADY_DEAD) {
-	    Tcl_AppendResult(interp,
-		    "can't create window: parent has been destroyed", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't create window: parent has been destroyed", -1));
+	    Tcl_SetErrorCode(interp, "TK", "CREATE", "DEAD_PARENT", NULL);
 	    return NULL;
 	} else if (parentPtr->flags & TK_CONTAINER) {
-	    Tcl_AppendResult(interp,
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		    "can't create window: its parent has -container = yes",
-		    NULL);
+		    -1));
+	    Tcl_SetErrorCode(interp, "TK", "CREATE", "CONTAINER", NULL);
 	    return NULL;
 	} else if (screenName == NULL) {
 	    TkWindow *winPtr = TkAllocWindow(parentPtr->dispPtr,
@@ -1176,8 +1188,9 @@ Tk_CreateWindowFromPath(
 
     p = strrchr(pathName, '.');
     if (p == NULL) {
-	Tcl_AppendResult(interp, "bad window path name \"", pathName,
-		"\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad window path name \"%s\"", pathName));
+	Tcl_SetErrorCode(interp, "TK", "VALUE", "WINDOW_PATH", NULL);
 	return NULL;
     }
     numChars = (int) (p-pathName);
@@ -1206,13 +1219,14 @@ Tk_CreateWindowFromPath(
 	return NULL;
     }
     if (((TkWindow *) parent)->flags & TK_ALREADY_DEAD) {
-	Tcl_AppendResult(interp,
-		"can't create window: parent has been destroyed", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"can't create window: parent has been destroyed", -1));
+	Tcl_SetErrorCode(interp, "TK", "CREATE", "DEAD_PARENT", NULL);
 	return NULL;
-    }
-    if (((TkWindow *) parent)->flags & TK_CONTAINER) {
-	Tcl_AppendResult(interp,
-		"can't create window: its parent has -container = yes", NULL);
+    } else if (((TkWindow *) parent)->flags & TK_CONTAINER) {
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"can't create window: its parent has -container = yes", -1));
+	Tcl_SetErrorCode(interp, "TK", "CREATE", "CONTAINER", NULL);
 	return NULL;
     }
 
@@ -1354,8 +1368,8 @@ Tk_DestroyWindow(
     }
 
     while (winPtr->childList != NULL) {
-	TkWindow *childPtr;
-	childPtr = winPtr->childList;
+	TkWindow *childPtr = winPtr->childList;
+
 	childPtr->flags |= TK_DONT_DESTROY_WINDOW;
 	Tk_DestroyWindow((Tk_Window) childPtr);
 	if (winPtr->childList == childPtr) {
@@ -1382,8 +1396,8 @@ Tk_DestroyWindow(
 	 * deleted, in which case TkpGetOtherWindow will return NULL.
 	 */
 
-	TkWindow *childPtr;
-	childPtr = TkpGetOtherWindow(winPtr);
+	TkWindow *childPtr = TkpGetOtherWindow(winPtr);
+
 	if (childPtr != NULL) {
 	    childPtr->flags |= TK_DONT_DESTROY_WINDOW;
 	    Tk_DestroyWindow((Tk_Window) childPtr);
@@ -1528,7 +1542,7 @@ Tk_DestroyWindow(
 	     */
 
 	    if ((winPtr->mainPtr->interp != NULL) &&
-		    (!Tcl_InterpDeleted(winPtr->mainPtr->interp))) {
+		    !Tcl_InterpDeleted(winPtr->mainPtr->interp)) {
 		for (cmdPtr = commands; cmdPtr->name != NULL; cmdPtr++) {
 		    Tcl_CreateCommand(winPtr->mainPtr->interp, cmdPtr->name,
 			    TkDeadAppCmd, NULL, NULL);
@@ -1613,7 +1627,7 @@ Tk_DestroyWindow(
 
 		TkCloseDisplay(dispPtr);
 	    }
-#endif
+#endif /* !WIN32 && NOT_YET */
 	}
     }
     Tcl_EventuallyFree(winPtr, TCL_DYNAMIC);
@@ -1751,6 +1765,7 @@ Tk_MakeWindowExist(
 	    if ((winPtr2->window != None)
 		    && !(winPtr2->flags & (TK_TOP_HIERARCHY|TK_REPARENTED))) {
 		XWindowChanges changes;
+
 		changes.sibling = winPtr2->window;
 		changes.stack_mode = Below;
 		XConfigureWindow(winPtr->display, winPtr->window,
@@ -2328,7 +2343,8 @@ Tk_NameToWindow(
 	 */
 
 	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "NULL main window", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj("NULL main window",-1));
+	    Tcl_SetErrorCode(interp, "TK", "NO_MAIN_WINDOW", NULL);
 	}
 	return NULL;
     }
@@ -2337,8 +2353,10 @@ Tk_NameToWindow(
 	    pathName);
     if (hPtr == NULL) {
 	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "bad window path name \"",
-		    pathName, "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad window path name \"%s\"", pathName));
+	    Tcl_SetErrorCode(interp, "TK", "LOOKUP", "WINDOW", pathName,
+		    NULL);
 	}
 	return NULL;
     }
@@ -2432,8 +2450,8 @@ Tcl_Interp *
 Tk_Interp(
     Tk_Window tkwin)
 {
-    if (tkwin != NULL && ((TkWindow *)tkwin)->mainPtr != NULL) {
-	return ((TkWindow *)tkwin)->mainPtr->interp;
+    if (tkwin != NULL && ((TkWindow *) tkwin)->mainPtr != NULL) {
+	return ((TkWindow *) tkwin)->mainPtr->interp;
     }
     return NULL;
 }
@@ -2591,9 +2609,8 @@ Tk_RestackWindow(
 
     if (winPtr->window != None) {
 	XWindowChanges changes;
-	unsigned int mask;
+	unsigned int mask = CWStackMode;
 
-	mask = CWStackMode;
 	changes.stack_mode = Above;
 	for (otherPtr = winPtr->nextPtr; otherPtr != NULL;
 		otherPtr = otherPtr->nextPtr) {
@@ -2652,7 +2669,9 @@ Tk_MainWindow(
 	    return (Tk_Window) mainPtr->winPtr;
 	}
     }
-    Tcl_SetResult(interp, "this isn't a Tk application", TCL_STATIC);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+	    "this isn't a Tk application", -1));
+    Tcl_SetErrorCode(interp, "TK", "NO_MAIN_WINDOW", NULL);
     return NULL;
 }
 
@@ -2840,44 +2859,47 @@ static HMODULE tkcygwindll = NULL;
 /*
  * Run Tk_MainEx from libtk8.?.dll
  *
- * This function is only ever called from wish8.4.exe, the cygwin
- * port of Tcl. This means that the system encoding is utf-8,
- * so we don't have to do any encoding conversions.
+ * This function is only ever called from wish8.4.exe, the cygwin port of Tcl.
+ * This means that the system encoding is utf-8, so we don't have to do any
+ * encoding conversions.
  */
+
 int
-TkCygwinMainEx(argc, argv, appInitProc, interp)
-    int argc;				/* Number of arguments. */
-    char **argv;			/* Array of argument strings. */
-    Tcl_AppInitProc *appInitProc;	/* Application-specific initialization
-					 * procedure to call after most
-					 * initialization but before starting
-					 * to execute commands. */
-    Tcl_Interp *interp;
+TkCygwinMainEx(
+    int argc,			/* Number of arguments. */
+    char **argv,		/* Array of argument strings. */
+    Tcl_AppInitProc *appInitProc,
+				/* Application-specific initialization
+				 * procedure to call after most initialization
+				 * but before starting to execute commands. */
+    Tcl_Interp *interp)
 {
     TCHAR name[MAX_PATH];
     int len;
-    void (*sym)(int, char **, Tcl_AppInitProc *, Tcl_Interp *);
+    void (*tkmainex)(int, char **, Tcl_AppInitProc *, Tcl_Interp *);
 
     /* construct "<path>/libtk8.?.dll", from "<path>/tk8?.dll" */
-	len = GetModuleFileNameW(Tk_GetHINSTANCE(), name, MAX_PATH);
-	name[len-2] = TEXT('.');
-	name[len-1] = name[len-5];
-	_tcscpy(name+len, TEXT(".dll"));
-	memcpy(name+len-8, TEXT("libtk8"), 6 * sizeof(TCHAR));
-
-	tkcygwindll = LoadLibrary(name);
-	if (!tkcygwindll) {
-	    /* dll is not present */
-	    return 0;
-	}
-	sym = (void (*)(int, char **, Tcl_AppInitProc *, Tcl_Interp *)) GetProcAddress(tkcygwindll, "Tk_MainEx");
-	if (!sym) {
-		return 0;
-	}
-	sym(argc, argv, appInitProc, interp);
+    len = GetModuleFileNameW(Tk_GetHINSTANCE(), name, MAX_PATH);
+    name[len-2] = TEXT('.');
+    name[len-1] = name[len-5];
+    _tcscpy(name+len, TEXT(".dll"));
+    memcpy(name+len-8, TEXT("libtk8"), 6 * sizeof(TCHAR));
+
+    tkcygwindll = LoadLibrary(name);
+    if (!tkcygwindll) {
+	/* dll is not present */
+	return 0;
+    }
+    tkmainex = (void (*)(int, char **, Tcl_AppInitProc *, Tcl_Interp *))
+	    GetProcAddress(tkcygwindll, "Tk_MainEx");
+    if (!tkmainex) {
+	return 0;
+    }
+    tkmainex(argc, argv, appInitProc, interp);
     return 1;
 }
-#endif
+#endif /* __WIN32__ && !__WIN64__ */
+
 /*
  *----------------------------------------------------------------------
  *
@@ -2907,14 +2929,14 @@ Tk_Init(
 {
 #if defined(__WIN32__) && !defined(__WIN64__)
     if (tkcygwindll) {
-	int (*sym)(Tcl_Interp *);
+	int (*tkinit)(Tcl_Interp *);
 
-	sym = (int (*)(Tcl_Interp *)) GetProcAddress(tkcygwindll, "Tk_Init");
-	if (sym) {
-	    return sym(interp);
+	tkinit = (int(*)(Tcl_Interp *)) GetProcAddress(tkcygwindll,"Tk_Init");
+	if (tkinit) {
+	    return tkinit(interp);
 	}
     }
-#endif
+#endif /* __WIN32__ && !__WIN64__ */
     return Initialize(interp);
 }
 
@@ -2980,14 +3002,15 @@ Tk_SafeInit(
 
 #if defined(__WIN32__) && !defined(__WIN64__)
     if (tkcygwindll) {
-	int (*sym)(Tcl_Interp *);
+	int (*tksafeinit)(Tcl_Interp *);
 
-	sym = (int (*)(Tcl_Interp *)) GetProcAddress(tkcygwindll, "Tk_SafeInit");
-	if (sym) {
-	    return sym(interp);
+	tksafeinit = (int (*)(Tcl_Interp *))
+		GetProcAddress(tkcygwindll, "Tk_SafeInit");
+	if (tksafeinit) {
+	    return tksafeinit(interp);
 	}
     }
-#endif
+#endif /* __WIN32__ && !__WIN64__ */
     return Initialize(interp);
 }
 
@@ -2998,7 +3021,8 @@ MODULE_SCOPE const TkStubs tkStubs;
  *
  * Initialize --
  *
- *	???TODO???
+ *	The core of the initialization code for Tk, called from Tk_Init and
+ *	Tk_SafeInit.
  *
  * Results:
  *	A standard Tcl result. Also leaves an error message in the interp's
@@ -3082,7 +3106,9 @@ Initialize(
 	while (1) {
 	    master = Tcl_GetMaster(master);
 	    if (master == NULL) {
-		Tcl_AppendResult(interp, "NULL master", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"no controlling master interpreter", -1));
+		Tcl_SetErrorCode(interp, "TK", "SAFE", "NO_MASTER", NULL);
 		code = TCL_ERROR;
 		goto done;
 	    }
@@ -3098,7 +3124,9 @@ Initialize(
 
 	code = Tcl_GetInterpPath(master, interp);
 	if (code != TCL_OK) {
-	    Tcl_AppendResult(interp, "error in Tcl_GetInterpPath", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "error in Tcl_GetInterpPath", -1));
+	    Tcl_SetErrorCode(interp, "TK", "SAFE", "FAILED", NULL);
 	    goto done;
 	}
 
@@ -3123,8 +3151,9 @@ Initialize(
 	     */
 
 	    Tcl_DStringFree(&ds);
-	    Tcl_AppendResult(interp,
-		    "not allowed to start Tk by master's safe::TkInit", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "not allowed to start Tk by master's safe::TkInit", -1));
+	    Tcl_SetErrorCode(interp, "TK", "SAFE", "FAILED", NULL);
 	    goto done;
 	}
 	Tcl_DStringFree(&ds);
@@ -3389,6 +3418,7 @@ Tk_PkgInitStubsCheck(
     }
     return actualVersion;
 }
+
 /*
  * Local Variables:
  * mode: c
diff --git a/generic/ttk/ttkEntry.c b/generic/ttk/ttkEntry.c
index a3d0179..136d4af 100644
--- a/generic/ttk/ttkEntry.c
+++ b/generic/ttk/ttkEntry.c
@@ -1177,13 +1177,13 @@ static void EntryDisplay(void *clientData, Drawable d)
 
     textarea = Ttk_ClientRegion(entryPtr->core.layout, "textarea");
     showCursor =
-	   (entryPtr->core.flags & CURSOR_ON) != 0
+	   (entryPtr->core.flags & CURSOR_ON)
 	&& EntryEditable(entryPtr)
 	&& entryPtr->entry.insertPos >= leftIndex
 	&& entryPtr->entry.insertPos <= rightIndex
 	;
     showSelection =
-	   (entryPtr->core.state & TTK_STATE_DISABLED) == 0
+	   !(entryPtr->core.state & TTK_STATE_DISABLED)
 	&& selFirst > -1
 	&& selLast > leftIndex
 	&& selFirst <= rightIndex
@@ -1322,9 +1322,10 @@ EntryIndex(
 	*indexPtr = entryPtr->entry.xscroll.last;
     } else if (strncmp(string, "sel.", 4) == 0) {
 	if (entryPtr->entry.selectFirst < 0) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "selection isn't in widget ",
-		    Tk_PathName(entryPtr->core.tkwin), NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "selection isn't in widget %s",
+		    Tk_PathName(entryPtr->core.tkwin)));
+	    Tcl_SetErrorCode(interp, "TTK", "ENTRY", "NO_SELECTION", NULL);
 	    return TCL_ERROR;
 	}
 	if (strncmp(string, "sel.first", length) == 0) {
@@ -1376,8 +1377,9 @@ EntryIndex(
     return TCL_OK;
 
 badIndex:
-    Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp, "bad entry index \"", string, "\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad entry index \"%s\"", string));
+    Tcl_SetErrorCode(interp, "TTK", "ENTRY", "INDEX", NULL);
     return TCL_ERROR;
 }
 
@@ -1452,7 +1454,7 @@ EntryGetCommand(
 	Tcl_WrongNumArgs(interp, 2, objv, NULL);
 	return TCL_ERROR;
     }
-    Tcl_SetResult(interp, entryPtr->entry.string, TCL_VOLATILE);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(entryPtr->entry.string, -1));
     return TCL_OK;
 }
 
@@ -1782,9 +1784,9 @@ static int ComboboxCurrentCommand(
 	    return TCL_ERROR;
 	}
 	if (currentIndex < 0 || currentIndex >= nValues) {
-	    Tcl_AppendResult(interp,
-		    "Index ", Tcl_GetString(objv[2]), " out of range",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "Index %s out of range", Tcl_GetString(objv[2])));
+	    Tcl_SetErrorCode(interp, "TTK", "COMBOBOX", "IDX_RANGE", NULL);
 	    return TCL_ERROR;
 	}
 
diff --git a/generic/ttk/ttkFrame.c b/generic/ttk/ttkFrame.c
index 7860024..3e50a7f 100644
--- a/generic/ttk/ttkFrame.c
+++ b/generic/ttk/ttkFrame.c
@@ -206,10 +206,9 @@ int TtkGetLabelAnchorFromObj(
 
 error:
     if (interp) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp,
-	    "Bad label anchor specification ", Tcl_GetString(objPtr),
-	    NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Bad label anchor specification %s", Tcl_GetString(objPtr)));
+	Tcl_SetErrorCode(interp, "TTK", "LABEL", "ANCHOR", NULL);
     }
     return TCL_ERROR;
 }
diff --git a/generic/ttk/ttkImage.c b/generic/ttk/ttkImage.c
index 0de5fc0..1d455d9 100644
--- a/generic/ttk/ttkImage.c
+++ b/generic/ttk/ttkImage.c
@@ -59,9 +59,10 @@ TtkGetImageSpec(Tcl_Interp *interp, Tk_Window tkwin, Tcl_Obj *objPtr)
 
     if ((objc % 2) != 1) {
 	if (interp) {
-	    Tcl_SetResult(interp,
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		"image specification must contain an odd number of elements",
-		TCL_STATIC);
+		-1));
+	    Tcl_SetErrorCode(interp, "TTK", "IMAGE", "SPEC", NULL);
 	}
 	goto error;
     }
@@ -324,7 +325,9 @@ Ttk_CreateImageElement(
     int i;
 
     if (objc <= 0) {
-	Tcl_AppendResult(interp, "Must supply a base image", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"Must supply a base image", -1));
+	Tcl_SetErrorCode(interp, "TTK", "IMAGE", "BASE", NULL);
 	return TCL_ERROR;
     }
 
@@ -347,9 +350,9 @@ Ttk_CreateImageElement(
 	int option;
 
 	if (i == objc - 1) {
-	    Tcl_AppendResult(interp,
-		"Value for ", Tcl_GetString(objv[i]), " missing",
-		NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "Value for %s missing", Tcl_GetString(objv[i])));
+	    Tcl_SetErrorCode(interp, "TTK", "IMAGE", "VALUE", NULL);
 	    goto error;
 	}
 
@@ -362,12 +365,16 @@ Ttk_CreateImageElement(
 #endif
 
 	if (Tcl_GetIndexFromObj(interp, objv[i], optionStrings,
-		    "option", 0, &option) != TCL_OK) { goto error; }
+		"option", 0, &option) != TCL_OK) {
+	    goto error;
+	}
 
 	switch (option) {
 	    case O_BORDER:
 		if (Ttk_GetBorderFromObj(interp, objv[i+1], &imageData->border)
-			!= TCL_OK) { goto error; }
+			!= TCL_OK) {
+		    goto error;
+		}
 		if (!padding_specified) {
 		    imageData->padding = imageData->border;
 		}
diff --git a/generic/ttk/ttkLayout.c b/generic/ttk/ttkLayout.c
index d248dcb..de9d795 100644
--- a/generic/ttk/ttkLayout.c
+++ b/generic/ttk/ttkLayout.c
@@ -326,8 +326,9 @@ int Ttk_GetPaddingFromObj(
 
     if (padc > 4) {
 	if (interp) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "Wrong #elements in padding spec", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "Wrong #elements in padding spec", -1));
+	    Tcl_SetErrorCode(interp, "TTK", "VALUE", "PADDING", NULL);
 	}
 	goto error;
     }
@@ -363,8 +364,9 @@ int Ttk_GetBorderFromObj(Tcl_Interp *interp, Tcl_Obj *objPtr, Ttk_Padding *pad)
 
     if (padc > 4) {
 	if (interp) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "Wrong #elements in border spec", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "Wrong #elements in padding spec", -1));
+	    Tcl_SetErrorCode(interp, "TTK", "VALUE", "BORDER", NULL);
 	}
 	goto error;
     }
@@ -476,11 +478,10 @@ int Ttk_GetStickyFromObj(
 	    case 's': case 'S': sticky |= TTK_STICK_S; break;
 	    default:
 	    	if (interp) {
-		    Tcl_ResetResult(interp);
-		    Tcl_AppendResult(interp,
-			"Bad -sticky specification ",
-			Tcl_GetString(objPtr),
-			NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"Bad -sticky specification %s",
+			Tcl_GetString(objPtr)));
+		    Tcl_SetErrorCode(interp, "TTK", "VALUE", "STICKY", NULL);
 		}
 		return TCL_ERROR;
 	}
@@ -643,10 +644,10 @@ Ttk_LayoutTemplate Ttk_ParseLayoutTemplate(Tcl_Interp *interp, Tcl_Obj *objPtr)
 	    }
 
 	    if (++i >= objc) {
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp,
-			"Missing value for option ",Tcl_GetString(objv[i-1]),
-			NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"Missing value for option %s",
+			Tcl_GetString(objv[i-1])));
+		Tcl_SetErrorCode(interp, "TTK", "VALUE", "LAYOUT", NULL);
 		goto error;
 	    }
 
@@ -790,7 +791,7 @@ Tcl_Obj *Ttk_UnparseLayoutTemplate(Ttk_TemplateNode *node)
 		int side = 0;
 		unsigned sideFlags = flags & _TTK_MASK_PACK;
 
-		while ((sideFlags & TTK_PACK_LEFT) == 0) {
+		while (!(sideFlags & TTK_PACK_LEFT)) {
 		    ++side;
 		    sideFlags >>= 1;
 		}
@@ -799,9 +800,11 @@ Tcl_Obj *Ttk_UnparseLayoutTemplate(Ttk_TemplateNode *node)
 	    }
 	}
 
-	/* In Ttk_ParseLayoutTemplate, default -sticky is "nsew",
-	 * so always include this even if no sticky bits are set.
+	/*
+	 * In Ttk_ParseLayoutTemplate, default -sticky is "nsew", so always
+	 * include this even if no sticky bits are set.
 	 */
+
 	APPENDSTR("-sticky");
 	APPENDOBJ(Ttk_NewStickyObj(flags & _TTK_MASK_STICK));
 
@@ -875,8 +878,9 @@ Ttk_Layout Ttk_CreateLayout(
     Ttk_LayoutNode *bgnode;
 
     if (!layoutTemplate) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "Layout ", styleName, " not found", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Layout %s not found", styleName));
+	Tcl_SetErrorCode(interp, "TTK", "LOOKUP", "LAYOUT", styleName, NULL);
 	return 0;
     }
 
@@ -915,8 +919,9 @@ Ttk_CreateSublayout(
     layoutTemplate = Ttk_FindLayoutTemplate(themePtr, styleName);
 
     if (!layoutTemplate) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "Layout ", styleName, " not found", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Layout %s not found", styleName));
+	Tcl_SetErrorCode(interp, "TTK", "LOOKUP", "LAYOUT", styleName, NULL);
 	return 0;
     }
 
diff --git a/generic/ttk/ttkManager.c b/generic/ttk/ttkManager.c
index 256573f..cf98a6d 100644
--- a/generic/ttk/ttkManager.c
+++ b/generic/ttk/ttkManager.c
@@ -455,10 +455,9 @@ int Ttk_GetSlaveIndexFromObj(
      */
     if (Tcl_GetIntFromObj(NULL, objPtr, &slaveIndex) == TCL_OK) {
 	if (slaveIndex < 0 || slaveIndex >= mgr->nSlaves) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp,
-		"Slave index ", Tcl_GetString(objPtr), " out of bounds",
-		NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Slave index %d out of bounds", slaveIndex));
+	    Tcl_SetErrorCode(interp, "TTK", "SLAVE", "INDEX", NULL);
 	    return TCL_ERROR;
 	}
 	*indexPtr = slaveIndex;
@@ -467,23 +466,23 @@ int Ttk_GetSlaveIndexFromObj(
 
     /* Try interpreting as a slave window name;
      */
-    if (   (*string == '.')
-	&& (tkwin = Tk_NameToWindow(interp, string, mgr->masterWindow)))
-    {
+    if ((*string == '.') &&
+	    (tkwin = Tk_NameToWindow(interp, string, mgr->masterWindow))) {
 	slaveIndex = Ttk_SlaveIndex(mgr, tkwin);
 	if (slaveIndex < 0) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp,
-		string, " is not managed by ", Tk_PathName(mgr->masterWindow),
-		NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "%s is not managed by %s", string,
+		    Tk_PathName(mgr->masterWindow)));
+	    Tcl_SetErrorCode(interp, "TTK", "SLAVE", "MANAGER", NULL);
 	    return TCL_ERROR;
 	}
 	*indexPtr = slaveIndex;
 	return TCL_OK;
     }
 
-    Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp, "Invalid slave specification ", string, NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "Invalid slave specification %s", string));
+    Tcl_SetErrorCode(interp, "TTK", "SLAVE", "SPEC", NULL);
     return TCL_ERROR;
 }
 
@@ -542,10 +541,9 @@ int Ttk_Maintainable(Tcl_Interp *interp, Tk_Window slave, Tk_Window master)
     return 1;
 
 badWindow:
-    Tcl_AppendResult(interp,
-	"can't add ", Tk_PathName(slave),
-	" as slave of ", Tk_PathName(master),
-	NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf("can't add %s as slave of %s",
+	    Tk_PathName(slave), Tk_PathName(master)));
+    Tcl_SetErrorCode(interp, "TTK", "GEOMETRY", "MAINTAINABLE", NULL);
     return 0;
 }
 
diff --git a/generic/ttk/ttkNotebook.c b/generic/ttk/ttkNotebook.c
index 551f4a6..6849135 100644
--- a/generic/ttk/ttkNotebook.c
+++ b/generic/ttk/ttkNotebook.c
@@ -727,9 +727,9 @@ static int AddTab(
     }
 #if 0 /* can't happen */
     if (Ttk_SlaveIndex(nb->notebook.mgr, slaveWindow) >= 0) {
-	Tcl_AppendResult(interp,
-	    Tk_PathName(slaveWindow), " already added",
-	    NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf("%s already added",
+	    Tk_PathName(slaveWindow)));
+	Tcl_SetErrorCode(interp, "TTK", "NOTEBOOK", "PRESENT", NULL);
 	return TCL_ERROR;
     }
 #endif
@@ -859,10 +859,9 @@ static int GetTabIndex(
     int status = FindTabIndex(interp, nb, objPtr, index_rtn);
 
     if (status == TCL_OK && *index_rtn < 0) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp,
-	    "tab '", Tcl_GetString(objPtr), "' not found",
-	    NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "tab '%s' not found", Tcl_GetString(objPtr)));
+	Tcl_SetErrorCode(interp, "TTK", "NOTEBOOK", "TAB", NULL);
 	status = TCL_ERROR;
     }
     return status;
@@ -1082,7 +1081,8 @@ static int NotebookIdentifyCommand(
 	case IDENTIFY_ELEMENT:
 	    if (element) {
 		const char *elementName = Ttk_ElementName(element);
-		Tcl_SetObjResult(interp,Tcl_NewStringObj(elementName,-1));
+
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(elementName, -1));
 	    }
 	    break;
 	case IDENTIFY_TAB:
@@ -1173,10 +1173,10 @@ static int NotebookTabsCommand(
     result = Tcl_NewListObj(0, NULL);
     for (i = 0; i < Ttk_NumberSlaves(mgr); ++i) {
 	const char *pathName = Tk_PathName(Ttk_SlaveWindow(mgr,i));
-	Tcl_ListObjAppendElement(interp, result, Tcl_NewStringObj(pathName,-1));
+
+	Tcl_ListObjAppendElement(NULL, result, Tcl_NewStringObj(pathName,-1));
     }
     Tcl_SetObjResult(interp, result);
-
     return TCL_OK;
 }
 
diff --git a/generic/ttk/ttkPanedwindow.c b/generic/ttk/ttkPanedwindow.c
index b301372..f4b14c9 100644
--- a/generic/ttk/ttkPanedwindow.c
+++ b/generic/ttk/ttkPanedwindow.c
@@ -157,7 +157,9 @@ static int ConfigurePane(
     /* Sanity-check:
      */
     if (pane->weight < 0) {
-	Tcl_AppendResult(interp, "-weight must be nonnegative", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"-weight must be nonnegative", -1));
+	Tcl_SetErrorCode(interp, "TTK", "PANE", "WEIGHT", NULL);
 	goto error;
     }
 
@@ -419,9 +421,9 @@ static int AddPane(
 	return TCL_ERROR;
     }
     if (Ttk_SlaveIndex(pw->paned.mgr, slaveWindow) >= 0) {
-	Tcl_AppendResult(interp,
-	    Tk_PathName(slaveWindow), " already added",
-	    NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"%s already added", Tk_PathName(slaveWindow)));
+	Tcl_SetErrorCode(interp, "TTK", "PANE", "PRESENT", NULL);
 	return TCL_ERROR;
     }
 
@@ -844,9 +846,9 @@ static int PanedSashposCommand(
 	return TCL_ERROR;
     }
     if (sashIndex < 0 || sashIndex >= Ttk_NumberSlaves(pw->paned.mgr) - 1) {
-	Tcl_AppendResult(interp,
-	    "sash index ", Tcl_GetString(objv[2]), " out of range",
-	    NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "sash index %d out of range", sashIndex));
+	Tcl_SetErrorCode(interp, "TTK", "PANE", "SASH_INDEX", NULL);
 	return TCL_ERROR;
     }
 
diff --git a/generic/ttk/ttkState.c b/generic/ttk/ttkState.c
index a71ae21..c34b900 100644
--- a/generic/ttk/ttkState.c
+++ b/generic/ttk/ttkState.c
@@ -98,8 +98,9 @@ static int StateSpecSetFromAny(Tcl_Interp *interp, Tcl_Obj *objPtr)
 
     	if (stateNames[j] == 0) {
 	    if (interp) {
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "Invalid state name ", stateName,NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"Invalid state name %s", stateName));
+		Tcl_SetErrorCode(interp, "TTK", "VALUE", "STATE", NULL);
 	    }
 	    return TCL_ERROR;
 	}
@@ -216,8 +217,8 @@ Tcl_Obj *Ttk_StateMapLookup(
 	    return specs[j+1];
     }
     if (interp) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "No match in state map", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj("No match in state map", -1));
+	Tcl_SetErrorCode(interp, "TTK", "STATE", "UNMATCHED", NULL);
     }
     return NULL;
 }
@@ -240,10 +241,11 @@ Ttk_StateMap Ttk_GetStateMapFromObj(
 	return NULL;
 
     if (nSpecs % 2 != 0) {
-	if (interp)
-	    Tcl_SetResult(interp,
-		    "State map must have an even number of elements",
-		    TCL_STATIC);
+	if (interp) {
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "State map must have an even number of elements", -1));
+	    Tcl_SetErrorCode(interp, "TTK", "VALUE", "STATEMAP", NULL);
+	}
 	return 0;
     }
 
diff --git a/generic/ttk/ttkTheme.c b/generic/ttk/ttkTheme.c
index b0e9171..5097abc 100644
--- a/generic/ttk/ttkTheme.c
+++ b/generic/ttk/ttkTheme.c
@@ -548,8 +548,9 @@ Ttk_CreateTheme(
 
     entryPtr = Tcl_CreateHashEntry(&pkgPtr->themeTable, name, &newEntry);
     if (!newEntry) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "Theme ", name, " already exists", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Theme %s already exists", name));
+	Tcl_SetErrorCode(interp, "TTK", "THEME", "EXISTS", NULL);
 	return NULL;
     }
 
@@ -591,8 +592,9 @@ static Ttk_Theme LookupTheme(
 
     entryPtr = Tcl_FindHashEntry(&pkgPtr->themeTable, name);
     if (!entryPtr) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "theme \"", name, "\" doesn't exist", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"theme \"%s\" doesn't exist", name));
+	Tcl_SetErrorCode(interp, "TTK", "LOOKUP", "THEME", name, NULL);
 	return NULL;
     }
 
@@ -875,9 +877,10 @@ Ttk_ElementClass *Ttk_RegisterElement(
     if (specPtr->version != TK_STYLE_VERSION_2) {
 	/* Version mismatch */
 	if (interp) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "Internal error: Ttk_RegisterElement (",
-		name, "): invalid version",
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Internal error: Ttk_RegisterElement (%s): invalid version",
+		name));
+	    Tcl_SetErrorCode(interp, "TTK", "REGISTER_ELEMENT", "VERSION",
 		NULL);
 	}
 	return 0;
@@ -887,7 +890,9 @@ Ttk_ElementClass *Ttk_RegisterElement(
     if (!newEntry) {
 	if (interp) {
 	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "Duplicate element ", name, NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Duplicate element %s", name));
+	    Tcl_SetErrorCode(interp, "TTK", "REGISTER_ELEMENT", "DUPE", NULL);
 	}
 	return 0;
     }
@@ -1355,8 +1360,9 @@ static int StyleThemeCurrentCmd(
     }
 
     if (name == NULL) {
-	Tcl_SetObjResult(interp,
-	    Tcl_NewStringObj("error: failed to get theme name", -1));
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"error: failed to get theme name", -1));
+	Tcl_SetErrorCode(interp, "TTK", "THEME", "NAMELESS", NULL);
 	return TCL_ERROR;
     }
 
@@ -1491,7 +1497,10 @@ static int StyleElementCreateCmd(
 
     entryPtr = Tcl_FindHashEntry(&pkgPtr->factoryTable, factoryName);
     if (!entryPtr) {
-	Tcl_AppendResult(interp, "No such element type ", factoryName, NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"No such element type %s", factoryName));
+	Tcl_SetErrorCode(interp, "TTK", "LOOKUP", "ELEMENT_TYPE", factoryName,
+		NULL);
 	return TCL_ERROR;
     }
 
@@ -1550,7 +1559,9 @@ static int StyleElementOptionsCmd(
 	return TCL_OK;
     }
 
-    Tcl_AppendResult(interp, "element ", elementName, " not found", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	"element %s not found", elementName));
+    Tcl_SetErrorCode(interp, "TTK", "LOOKUP", "ELEMENT", elementName, NULL);
     return TCL_ERROR;
 }
 
@@ -1574,7 +1585,10 @@ static int StyleLayoutCmd(
     if (objc == 3) {
 	layoutTemplate = Ttk_FindLayoutTemplate(theme, layoutName);
 	if (!layoutTemplate) {
-	    Tcl_AppendResult(interp, "Layout ", layoutName, " not found", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Layout %s not found", layoutName));
+	    Tcl_SetErrorCode(interp, "TTK", "LOOKUP", "LAYOUT", layoutName,
+		NULL);
 	    return TCL_ERROR;
 	}
 	Tcl_SetObjResult(interp, Ttk_UnparseLayoutTemplate(layoutTemplate));
diff --git a/generic/ttk/ttkTreeview.c b/generic/ttk/ttkTreeview.c
index 1ed2742..dc0206c 100644
--- a/generic/ttk/ttkTreeview.c
+++ b/generic/ttk/ttkTreeview.c
@@ -534,21 +534,18 @@ static TreeColumn *GetColumn(
      */
     if (Tcl_GetIntFromObj(NULL, columnIDObj, &columnIndex) == TCL_OK) {
 	if (columnIndex < 0 || columnIndex >= tv->tree.nColumns) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp,
-		    "Column index ",
-		    Tcl_GetString(columnIDObj),
-		    " out of bounds",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "Column index %s out of bounds",
+		    Tcl_GetString(columnIDObj)));
+	    Tcl_SetErrorCode(interp, "TTK", "TREE", "COLBOUND", NULL);
 	    return NULL;
 	}
 
 	return tv->tree.columns + columnIndex;
     }
-    Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp,
-	"Invalid column index ", Tcl_GetString(columnIDObj),
-	NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	"Invalid column index %s", Tcl_GetString(columnIDObj)));
+    Tcl_SetErrorCode(interp, "TTK", "TREE", "COLUMN", NULL);
     return NULL;
 }
 
@@ -566,10 +563,9 @@ static TreeColumn *FindColumn(
 	    return tv->tree.displayColumns[colno];
 	}
 	/* else */
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp,
-	    "Column ", Tcl_GetString(columnIDObj), " out of range",
-	    NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "Column %s out of range", Tcl_GetString(columnIDObj)));
+	Tcl_SetErrorCode(interp, "TTK", "TREE", "COLUMN", NULL);
 	return NULL;
     }
 
@@ -587,8 +583,9 @@ static TreeItem *FindItem(
     Tcl_HashEntry *entryPtr =  Tcl_FindHashEntry(&tv->tree.items, itemName);
 
     if (!entryPtr) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "Item ", itemName, " not found", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Item %s not found", itemName));
+	Tcl_SetErrorCode(interp, "TTK", "TREE", "ITEM", NULL);
 	return 0;
     }
     return Tcl_GetHashValue(entryPtr);
@@ -1222,8 +1219,9 @@ static int ConfigureColumn(
     }
 
     if (mask & READONLY_OPTION) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "Attempt to change read-only option", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"Attempt to change read-only option", -1));
+	Tcl_SetErrorCode(interp, "TTK", "TREE", "READONLY", NULL);
 	goto error;
     }
 
@@ -1912,11 +1910,10 @@ static int AncestryCheck(
     TreeItem *p = parent;
     while (p) {
 	if (p == item) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp,
-		    "Cannot insert ", ItemName(tv, item),
-		    " as a descendant of ", ItemName(tv, parent),
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "Cannot insert %s as descendant of %s",
+		    ItemName(tv, item), ItemName(tv, parent)));
+	    Tcl_SetErrorCode(interp, "TTK", "TREE", "ANCESTRY", NULL);
 	    return 0;
 	}
 	p = p->parent;
@@ -2318,9 +2315,7 @@ static int TreeviewIdentifyCommand(
 
 	case I_COLUMN :
 	    if (colno >= 0) {
-		char dcolbuf[16];
-		sprintf(dcolbuf, "#%d", colno);
-		Tcl_SetObjResult(interp, Tcl_NewStringObj(dcolbuf, -1));
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf("#%d", colno));
 	    }
 	    break;
 
@@ -2488,9 +2483,9 @@ static int TreeviewSetCommand(
 	for (columnNumber=0; columnNumber<tv->tree.nColumns; ++columnNumber) {
 	    Tcl_ListObjIndex(interp, item->valuesObj, columnNumber, &value);
 	    if (value) {
-		Tcl_ListObjAppendElement(interp, result,
+		Tcl_ListObjAppendElement(NULL, result,
 			tv->tree.columns[columnNumber].idObj);
-		Tcl_ListObjAppendElement(interp, result, value);
+		Tcl_ListObjAppendElement(NULL, result, value);
 	    }
 	}
 	Tcl_SetObjResult(interp, result);
@@ -2504,7 +2499,9 @@ static int TreeviewSetCommand(
 
     if (column == &tv->tree.column0) {
 	/* @@@ Maybe set -text here instead? */
-	Tcl_AppendResult(interp, "Display column #0 cannot be set", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"Display column #0 cannot be set", -1));
+	Tcl_SetErrorCode(interp, "TTK", "TREE", "COLUMN_0", NULL);
 	return TCL_ERROR;
     }
 
@@ -2587,9 +2584,12 @@ static int TreeviewInsertCommand(
     objc -= 4; objv += 4;
     if (objc >= 2 && !strcmp("-id", Tcl_GetString(objv[0]))) {
 	const char *itemName = Tcl_GetString(objv[1]);
+
 	entryPtr = Tcl_CreateHashEntry(&tv->tree.items, itemName, &isNew);
 	if (!isNew) {
-	    Tcl_AppendResult(interp, "Item ",itemName," already exists",NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Item %s already exists", itemName));
+	    Tcl_SetErrorCode(interp, "TTK", "TREE", "ITEM_EXISTS", NULL);
 	    return TCL_ERROR;
 	}
 	objc -= 2; objv += 2;
@@ -2646,7 +2646,9 @@ static int TreeviewDetachCommand(
     /* Sanity-check */
     for (i = 0; items[i]; ++i) {
 	if (items[i] == tv->tree.root) {
-	    Tcl_AppendResult(interp, "Cannot detach root item", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"Cannot detach root item", -1));
+	    Tcl_SetErrorCode(interp, "TTK", "TREE", "ROOT", NULL);
 	    ckfree(items);
 	    return TCL_ERROR;
 	}
@@ -2694,7 +2696,9 @@ static int TreeviewDeleteCommand(
     for (i=0; items[i]; ++i) {
 	if (items[i] == tv->tree.root) {
 	    ckfree(items);
-	    Tcl_AppendResult(interp, "Cannot delete root item", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"Cannot delete root item", -1));
+	    Tcl_SetErrorCode(interp, "TTK", "TREE", "ROOT", NULL);
 	    return TCL_ERROR;
 	}
     }
@@ -2885,10 +2889,9 @@ static int TreeviewDragCommand(
 	left = right;
     }
 
-    Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp,
-	"column ", Tcl_GetString(objv[2]), " is not displayed",
-	NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	"column %s is not displayed", Tcl_GetString(objv[2])));
+    Tcl_SetErrorCode(interp, "TTK", "TREE", "COLUMN_INVISIBLE", NULL);
     return TCL_ERROR;
 }
 
@@ -2953,8 +2956,7 @@ static int TreeviewSelectionCommand(
     }
 
     if (Tcl_GetIndexFromObj(interp, objv[2], selopStrings,
-	    "selection operation", 0, &selop) != TCL_OK)
-    {
+	    "selection operation", 0, &selop) != TCL_OK) {
 	return TCL_ERROR;
     }
 
@@ -3040,10 +3042,10 @@ static int TreeviewTagBindCommand(
 	     */
 	    if (mask & (~TreeviewBindEventMask)) {
 		Tk_DeleteBinding(interp, bindingTable, tag, sequence);
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "unsupported event ", sequence,
-		    "\nonly key, button, motion, and virtual events supported",
-		    NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "unsupported event %s\nonly key, button, motion, and"
+		    " virtual events supported", sequence));
+		Tcl_SetErrorCode(interp, "TTK", "TREE", "BIND_EVENTS", NULL);
 		return TCL_ERROR;
 	    }
 	}
diff --git a/generic/ttk/ttkWidget.c b/generic/ttk/ttkWidget.c
index d5e0484..016653d 100644
--- a/generic/ttk/ttkWidget.c
+++ b/generic/ttk/ttkWidget.c
@@ -440,7 +440,8 @@ int TtkWidgetConstructorObjCmd(
 
 error:
     if (WidgetDestroyed(corePtr)) {
-	Tcl_SetResult(interp, "Widget has been destroyed", TCL_STATIC);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"widget has been destroyed", -1));
     } else {
 	Tk_DestroyWindow(tkwin);
     }
@@ -634,8 +635,8 @@ int TtkWidgetConfigureCommand(
 	    return status;
 
 	if (mask & READONLY_OPTION) {
-	    Tcl_SetResult(interp,
-		    "Attempt to change read-only option", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "attempt to change read-only option", -1));
 	    Tk_RestoreSavedOptions(&savedOptions);
 	    return TCL_ERROR;
 	}
@@ -649,7 +650,8 @@ int TtkWidgetConfigureCommand(
 
 	status = corePtr->widgetSpec->postConfigureProc(interp,recordPtr,mask);
 	if (WidgetDestroyed(corePtr)) {
-	    Tcl_SetResult(interp, "Widget has been destroyed", TCL_STATIC);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "widget has been destroyed", -1));
 	    status = TCL_ERROR;
 	}
 	if (status != TCL_OK) {