consistent error formatting, added error codes

14 files changed, 321 insertions, 223 deletions

diff --git a/generic/tkBind.c b/generic/tkBind.c
index 0c50368..c051c7a 100644
--- a/generic/tkBind.c
+++ b/generic/tkBind.c
@@ -2924,8 +2924,9 @@ 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", "EVENT", "FOREIGN_TARGET", NULL);
 	return TCL_ERROR;
     }
@@ -3024,8 +3025,8 @@ 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;
 	}
@@ -3167,16 +3168,16 @@ HandleEventGenerate(
 	    value = Tcl_GetString(valuePtr);
 	    keysym = TkStringToKeysym(value);
 	    if (keysym == NoSymbol) {
-		Tcl_AppendResult(interp, "unknown keysym \"", value, "\"",
-			NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"unknown keysym \"%s\"", value));
 		Tcl_SetErrorCode(interp, "TK", "LOOKUP", "KEYSYM", 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", NULL);
 		return TCL_ERROR;
 	    }
@@ -3406,8 +3407,9 @@ 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;
     }
@@ -3502,7 +3504,8 @@ 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", NULL);
     return TCL_ERROR;
 }
@@ -3566,8 +3569,8 @@ 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;
     }
@@ -3937,8 +3940,9 @@ ParseEventDescription(
 	    } else if (eventFlags & KEY) {
 		goto getKeysym;
 	    } else if ((eventFlags & BUTTON) == 0) {
-		Tcl_AppendResult(interp, "specified button \"", field,
-			"\" for non-button event", NULL);
+		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;
@@ -3949,8 +3953,8 @@ 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", NULL);
 		count = 0;
 		goto done;
@@ -3959,8 +3963,8 @@ ParseEventDescription(
 		patPtr->eventType = KeyPress;
 		eventMask = KeyPressMask;
 	    } else if ((eventFlags & KEY) == 0) {
-		Tcl_AppendResult(interp, "specified keysym \"", field,
-			"\" for non-key event", NULL);
+		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;
diff --git a/generic/tkBitmap.c b/generic/tkBitmap.c
index 5349fd5..1c28977 100644
--- a/generic/tkBitmap.c
+++ b/generic/tkBitmap.c
@@ -342,8 +342,9 @@ GetBitmap(
 	int result;
 
 	if (Tcl_IsSafe(interp)) {
-	    Tcl_AppendResult(interp, "can't specify bitmap with '@' in a",
-		    " safe interpreter", NULL);
+	    Tcl_SetResult(interp,
+		    "can't specify bitmap with '@' in a safe interpreter",
+		    TCL_STATIC);
 	    Tcl_SetErrorCode(interp, "TK", "SAFE", "BITMAP_FILE", NULL);
 	    goto error;
 	}
@@ -364,8 +365,8 @@ 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);
@@ -386,8 +387,8 @@ 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", NULL);
 		}
 		goto error;
@@ -490,8 +491,8 @@ 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;
     }
diff --git a/generic/tkBusy.c b/generic/tkBusy.c
index 5439969..8fd53fa 100644
--- a/generic/tkBusy.c
+++ b/generic/tkBusy.c
@@ -687,8 +687,8 @@ 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", NULL);
 	return NULL;
     }
diff --git a/generic/tkCanvArc.c b/generic/tkCanvArc.c
index d8a8062..434ca66 100644
--- a/generic/tkCanvArc.c
+++ b/generic/tkCanvArc.c
@@ -359,6 +359,8 @@ ArcCoords(
 	    } else if (objc != 4) {
 		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 			"wrong # coordinates: expected 4, got %d", objc));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "ARC",
+			NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -376,6 +378,7 @@ ArcCoords(
     } else {
 	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;
@@ -2013,8 +2016,10 @@ 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", "ARCSTYLE", NULL);
     *stylePtr = PIESLICE_STYLE;
     return TCL_ERROR;
 }
diff --git a/generic/tkCanvBmap.c b/generic/tkCanvBmap.c
index adaa184..bf4c78f 100644
--- a/generic/tkCanvBmap.c
+++ b/generic/tkCanvBmap.c
@@ -260,6 +260,8 @@ BitmapCoords(
 	    } else if (objc != 2) {
 		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 			"wrong # coordinates: expected 2, got %d", objc));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "BITMAP",
+			NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -273,6 +275,7 @@ BitmapCoords(
     } else {
 	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;
@@ -934,8 +937,9 @@ BitmapToPostscript(
 	}
 	if (width > 60000) {
 	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "can't generate Postscript",
-		    " for bitmaps more than 60000 pixels wide", NULL);
+	    Tcl_SetResult(interp, "can't generate Postscript for bitmaps more"
+		    " than 60000 pixels wide", TCL_STATIC);
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "MEMLIMIT", NULL);
 	    return TCL_ERROR;
 	}
 	rowsAtOnce = 60000/width;
diff --git a/generic/tkCanvImg.c b/generic/tkCanvImg.c
index b92659b..172f26d 100644
--- a/generic/tkCanvImg.c
+++ b/generic/tkCanvImg.c
@@ -245,10 +245,13 @@ ImageCoords(
 	    } else if (objc != 2) {
 		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;
@@ -257,6 +260,7 @@ ImageCoords(
     } else {
 	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;
diff --git a/generic/tkCanvLine.c b/generic/tkCanvLine.c
index e2dd8d3..d631c64 100644
--- a/generic/tkCanvLine.c
+++ b/generic/tkCanvLine.c
@@ -394,10 +394,12 @@ LineCoords(
 	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) {
 	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;
     }
 
@@ -1748,15 +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;
@@ -1797,6 +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", "ITEMINDEX", "LINE", NULL);
+    return TCL_ERROR;
 }
 
 /*
@@ -1910,8 +1915,10 @@ ParseArrowShape(
 
   syntaxError:
     Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp, "bad arrow shape \"", value,
-	    "\": must be list with three numbers", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad arrow shape \"%s\": must be list with three numbers",
+	    value));
+    Tcl_SetErrorCode(interp, "TK", "CANVAS", "ARROWSHAPE", NULL);
     if (argv != NULL) {
 	ckfree(argv);
     }
@@ -2012,8 +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;
 }
diff --git a/generic/tkCanvPoly.c b/generic/tkCanvPoly.c
index 943ef0b..da47a3f 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", "ITEMINDEX", "POLY", NULL);
     return TCL_ERROR;
 }
 
diff --git a/generic/tkCanvPs.c b/generic/tkCanvPs.c
index 69c9cfb..e259a71 100644
--- a/generic/tkCanvPs.c
+++ b/generic/tkCanvPs.c
@@ -166,6 +166,7 @@ TkCanvPostscriptCmd(
     TkPostscriptInfo psInfo, *psInfoPtr = &psInfo;
     Tk_PostscriptInfo oldInfoPtr;
     int result;
+    int written;
     Tk_Item *itemPtr;
 #define STRING_LENGTH 400
     char string[STRING_LENGTH+1];
@@ -321,8 +322,11 @@ 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 +337,9 @@ TkCanvPostscriptCmd(
 	 */
 
 	if (psInfo.channelName != NULL) {
-	    Tcl_AppendResult(interp, "can't specify both -file",
-		    " and -channel", NULL);
+	    Tcl_SetResult(interp, "can't specify both -file and -channel",
+		    TCL_STATIC);
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "USAGE", NULL);
 	    result = TCL_ERROR;
 	    goto cleanup;
 	}
@@ -345,8 +350,9 @@ TkCanvPostscriptCmd(
 	 */
 
 	if (Tcl_IsSafe(interp)) {
-	    Tcl_AppendResult(interp, "can't specify -file in a",
-		    " safe interpreter", NULL);
+	    Tcl_SetResult(interp, "can't specify -file in a safe interpreter",
+		    TCL_STATIC);
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "PS", "SAFE", NULL);
 	    result = TCL_ERROR;
 	    goto cleanup;
 	}
@@ -376,8 +382,10 @@ TkCanvPostscriptCmd(
 	    goto cleanup;
 	}
 	if ((mode & TCL_WRITABLE) == 0) {
-	    Tcl_AppendResult(interp, "channel \"", psInfo.channelName,
-		    "\" wasn't opened for writing", NULL);
+	    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;
 	}
@@ -475,8 +483,16 @@ TkCanvPostscriptCmd(
 	Tcl_AppendResult(interp, Tcl_GetString(preambleObj), NULL);
 
 	if (psInfo.chan != NULL) {
-	    Tcl_Write(psInfo.chan, Tcl_GetStringResult(interp), -1);
-	    Tcl_ResetResult(canvasPtr->interp);
+	    written = Tcl_WriteObj(psInfo.chan, Tcl_GetObjResult(interp));
+	    Tcl_ResetResult(interp);
+	    if (written == -1) {
+	    channelWriteFailed:
+		Tcl_AppendResult(interp,
+			"problem writing postscript data to channel: ",
+			Tcl_PosixError(interp), NULL);
+		result = TCL_ERROR;
+		goto cleanup;
+	    }
 	}
 
 	/*
@@ -522,8 +538,11 @@ TkCanvPostscriptCmd(
 		" lineto closepath clip newpath\n", NULL);
     }
     if (psInfo.chan != NULL) {
-	Tcl_Write(psInfo.chan, Tcl_GetStringResult(interp), -1);
-	Tcl_ResetResult(canvasPtr->interp);
+	written = Tcl_WriteObj(psInfo.chan, Tcl_GetObjResult(interp));
+	Tcl_ResetResult(interp);
+	if (written == -1) {
+	    goto channelWriteFailed;
+	}
     }
 
     /*
@@ -555,8 +574,11 @@ TkCanvPostscriptCmd(
 	}
 	Tcl_AppendResult(interp, "grestore\n", NULL);
 	if (psInfo.chan != NULL) {
-	    Tcl_Write(psInfo.chan, Tcl_GetStringResult(interp), -1);
+	    written = Tcl_WriteObj(psInfo.chan, Tcl_GetObjResult(interp));
 	    Tcl_ResetResult(interp);
+	    if (written == -1) {
+		goto channelWriteFailed;
+	    }
 	}
     }
 
@@ -570,8 +592,11 @@ TkCanvPostscriptCmd(
 		"%%Trailer\nend\n%%EOF\n", NULL);
     }
     if (psInfo.chan != NULL) {
-	Tcl_Write(psInfo.chan, Tcl_GetStringResult(interp), -1);
-	Tcl_ResetResult(canvasPtr->interp);
+	Tcl_WriteObj(psInfo.chan, Tcl_GetObjResult(interp));
+	Tcl_ResetResult(interp);
+	if (written == -1) {
+	    goto channelWriteFailed;
+	}
     }
 
     /*
@@ -747,8 +772,11 @@ Tk_PostscriptFont(
 		    || 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;
 	    }
 
@@ -1079,7 +1107,8 @@ 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;
 }
 
@@ -1287,10 +1316,10 @@ 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;
     }
@@ -1480,10 +1509,10 @@ 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;
     }
 
diff --git a/generic/tkCanvText.c b/generic/tkCanvText.c
index 0861a21..a225646 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;
 }
 
@@ -1357,6 +1360,7 @@ GetTextIndex(
 	    && (strncmp(string, "sel.first", (unsigned) length) == 0)) {
 	if (textInfoPtr->selItemPtr != itemPtr) {
 	    Tcl_SetResult(interp, "selection isn't in item", TCL_STATIC);
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "UNSELECTED", NULL);
 	    return TCL_ERROR;
 	}
 	*indexPtr = textInfoPtr->selectFirst;
@@ -1364,6 +1368,7 @@ GetTextIndex(
 	    && (strncmp(string, "sel.last", (unsigned) length) == 0)) {
 	if (textInfoPtr->selItemPtr != itemPtr) {
 	    Tcl_SetResult(interp, "selection isn't in item", TCL_STATIC);
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "UNSELECTED", NULL);
 	    return TCL_ERROR;
 	}
 	*indexPtr = textInfoPtr->selectLast;
@@ -1403,6 +1408,7 @@ GetTextIndex(
 
     badIndex:
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf("bad index \"%s\"", string));
+	Tcl_SetErrorCode(interp, "TK", "CANVAS", "ITEMINDEX", "TEXT", NULL);
 	return TCL_ERROR;
     }
     return TCL_OK;
diff --git a/generic/tkCanvUtil.c b/generic/tkCanvUtil.c
index 1a6a8c4..711d7aa 100644
--- a/generic/tkCanvUtil.c
+++ b/generic/tkCanvUtil.c
@@ -756,8 +756,9 @@ 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", NULL);
 		return TCL_ERROR;
 	    }
 	    smooth = &methods->smooth;
@@ -878,7 +879,7 @@ 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 +887,12 @@ 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 +910,10 @@ 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 +1255,9 @@ 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.
@@ -1731,7 +1734,7 @@ 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 +1745,7 @@ 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 +1836,7 @@ 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 0c54741..ef4cc03 100644
--- a/generic/tkCanvWind.c
+++ b/generic/tkCanvWind.c
@@ -259,6 +259,8 @@ WinItemCoords(
 	    } else if (objc != 2) {
 		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 			"wrong # coordinates: expected 2, got %d", objc));
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "WINDOW",
+			NULL);
 		return TCL_ERROR;
 	    }
 	}
@@ -271,6 +273,7 @@ WinItemCoords(
     } else {
 	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;
@@ -337,8 +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;
 		}
@@ -370,8 +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;
 }
@@ -842,7 +846,7 @@ CanvasPsWindow(
     Tcl_DStringInit(&buffer1);
     Tcl_DStringInit(&buffer2);
     Tcl_DStringGetResult(interp, &buffer2);
-    sprintf(buffer, "%s postscript -prolog 0\n", Tk_PathName(tkwin));
+    sprintf(buffer, "%s postscript -prolog 0", Tk_PathName(tkwin));
     result = Tcl_Eval(interp, buffer);
     Tcl_DStringGetResult(interp, &buffer1);
     Tcl_DStringResult(interp, &buffer2);
diff --git a/generic/tkCanvas.c b/generic/tkCanvas.c
index 14d8261..0cb8ccb 100644
--- a/generic/tkCanvas.c
+++ b/generic/tkCanvas.c
@@ -928,8 +928,9 @@ 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", "CANVASITEM", NULL);
 		result = TCL_ERROR;
 		goto done;
 	    }
@@ -953,8 +954,9 @@ 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", "CANVASITEM", NULL);
 		result = TCL_ERROR;
 		goto done;
 	    }
@@ -1030,10 +1032,10 @@ 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_SetResult(interp, "requested illegal events;"
+			" only key, button, motion, enter, leave, and virtual"
+			" events may be used", TCL_STATIC);
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "BAD_EVENTS", NULL);
 		result = TCL_ERROR;
 		goto done;
 	    }
@@ -1274,8 +1276,9 @@ 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", "CANVASITEM", NULL);
 	    result = TCL_ERROR;
 	    goto done;
 	}
@@ -1545,8 +1548,10 @@ 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 +1652,10 @@ 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 +1779,10 @@ 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;
 	    }
@@ -1848,6 +1857,7 @@ CanvasWidgetCmd(
 	}
 	if ((xScale == 0.0) || (yScale == 0.0)) {
 	    Tcl_SetResult(interp, "scale factor cannot be zero", TCL_STATIC);
+	    Tcl_SetErrorCode(interp, "TK", "CANVAS", "BAD_SCALE", NULL);
 	    result = TCL_ERROR;
 	    goto done;
 	}
@@ -1925,9 +1935,11 @@ 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 +2031,7 @@ 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 +2039,37 @@ 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 +2077,7 @@ 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 +2085,36 @@ 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 +2310,9 @@ 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", "SCROLLREGION", NULL);
 	badRegion:
 	    ckfree(canvasPtr->regionString);
 	    ckfree(argv2);
@@ -3583,8 +3592,11 @@ TagSearchScanExpr(
 
 	    case '!':		/* Negate next tag or subexpr */
 		if (looking_for_tag > 1) {
-		    Tcl_AppendResult(interp,
-			    "Too many '!' in tag search expression", NULL);
+		    Tcl_SetResult(interp,
+			    "too many '!' in tag search expression",
+			    TCL_STATIC);
+		    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			    "COMPLEXITY", NULL);
 		    return TCL_ERROR;
 		}
 		looking_for_tag++;
@@ -3631,15 +3643,19 @@ TagSearchScanExpr(
 		    *tag++ = c;
 		}
 		if (!found_endquote) {
-		    Tcl_AppendResult(interp,
-			    "Missing endquote in tag search expression",
-			    NULL);
+		    Tcl_SetResult(interp,
+			    "missing endquote in tag search expression",
+			    TCL_STATIC);
+		    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_SetResult(interp,
+			    "null quoted tag string in tag search expression",
+			    TCL_STATIC);
+		    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			    "EMPTY", NULL);
 		    return TCL_ERROR;
 		}
 		*tag++ = '\0';
@@ -3653,9 +3669,11 @@ TagSearchScanExpr(
 	    case '|':
 	    case '^':
 	    case ')':
-		Tcl_AppendResult(interp,
-			"Unexpected operator in tag search expression",
-			NULL);
+		Tcl_SetResult(interp,
+			"unexpected operator in tag search expression",
+			TCL_STATIC);
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			"UNEXPECTED", NULL);
 		return TCL_ERROR;
 
 	    default:		/* Unquoted tag string */
@@ -3716,8 +3734,11 @@ TagSearchScanExpr(
 	    case '&':		/* AND operator */
 		c = searchPtr->string[searchPtr->stringIndex++];
 		if (c != '&') {
-		    Tcl_AppendResult(interp,
-			    "Singleton '&' in tag search expression", NULL);
+		    Tcl_SetResult(interp,
+			    "singleton '&' in tag search expression",
+			    TCL_STATIC);
+		    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			    "INCOMPLETE_OP", NULL);
 		    return TCL_ERROR;
 		}
 		expr->uids[expr->index++] = searchUids->andUid;
@@ -3727,8 +3748,11 @@ TagSearchScanExpr(
 	    case '|':		/* OR operator */
 		c = searchPtr->string[searchPtr->stringIndex++];
 		if (c != '|') {
-		    Tcl_AppendResult(interp,
-			    "Singleton '|' in tag search expression", NULL);
+		    Tcl_SetResult(interp,
+			    "singleton '|' in tag search expression",
+			    TCL_STATIC);
+		    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH",
+			    "INCOMPLETE_OP", NULL);
 		    return TCL_ERROR;
 		}
 		expr->uids[expr->index++] = searchUids->orUid;
@@ -3745,8 +3769,10 @@ TagSearchScanExpr(
 		goto breakwhile;
 
 	    default:		/* syntax error */
-		Tcl_AppendResult(interp,
-			"Invalid boolean operator in tag search expression",
+		Tcl_SetResult(interp,
+			"invalid boolean operator in tag search expression",
+			TCL_STATIC);
+		Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH", "BAD_OP",
 			NULL);
 		return TCL_ERROR;
 	    }
@@ -3757,7 +3783,8 @@ TagSearchScanExpr(
     if (found_tag && !looking_for_tag) {
 	return TCL_OK;
     }
-    Tcl_AppendResult(interp, "Missing tag in tag search expression", NULL);
+    Tcl_SetResult(interp, "missing tag in tag search expression", TCL_STATIC);
+    Tcl_SetErrorCode(interp, "TK", "CANVAS", "SEARCH", "NO_TAG", NULL);
     return TCL_ERROR;
 }
 
@@ -4339,8 +4366,8 @@ 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 {
diff --git a/tests/canvas.test b/tests/canvas.test
index f5b33cc..2b0da48 100644
--- a/tests/canvas.test
+++ b/tests/canvas.test
@@ -406,7 +406,7 @@ test canvas-10.2 {check errors from tag expressions} -setup {
     .c create oval 20 260 40 280 -fill bisque -tag [list d "tag with spaces"]
 } -body {
     .c find withtag {&&c}
-} -returnCodes error -result {Unexpected operator in tag search expression}
+} -returnCodes error -result {unexpected operator in tag search expression}
 test canvas-10.3 {check errors from tag expressions} -setup {
     catch {destroy .c}
     canvas .c
@@ -414,7 +414,7 @@ test canvas-10.3 {check errors from tag expressions} -setup {
     .c create oval 20 260 40 280 -fill bisque -tag [list d "tag with spaces"]
 } -body {
     .c find withtag {!!c}
-} -returnCodes error -result {Too many '!' in tag search expression}
+} -returnCodes error -result {too many '!' in tag search expression}
 test canvas-10.4 {check errors from tag expressions} -setup {
     catch {destroy .c}
     canvas .c
@@ -422,7 +422,7 @@ test canvas-10.4 {check errors from tag expressions} -setup {
     .c create oval 20 260 40 280 -fill bisque -tag [list d "tag with spaces"]
 } -body {
     .c find withtag {b||}
-} -returnCodes error -result {Missing tag in tag search expression}
+} -returnCodes error -result {missing tag in tag search expression}
 test canvas-10.5 {check errors from tag expressions} -setup {
     catch {destroy .c}
     canvas .c
@@ -430,7 +430,7 @@ test canvas-10.5 {check errors from tag expressions} -setup {
     .c create oval 20 260 40 280 -fill bisque -tag [list d "tag with spaces"]
 } -body {
     .c find withtag {b&&(c||)}
-} -returnCodes error -result {Unexpected operator in tag search expression}
+} -returnCodes error -result {unexpected operator in tag search expression}
 test canvas-10.6 {check errors from tag expressions} -setup {
     catch {destroy .c}
     canvas .c
@@ -438,7 +438,7 @@ test canvas-10.6 {check errors from tag expressions} -setup {
     .c create oval 20 260 40 280 -fill bisque -tag [list d "tag with spaces"]
 } -body {
     .c find withtag {d&&""}
-} -returnCodes error -result {Null quoted tag string in tag search expression}
+} -returnCodes error -result {null quoted tag string in tag search expression}
 test canvas-10.7 {check errors from tag expressions} -setup {
     catch {destroy .c}
     canvas .c
@@ -446,7 +446,7 @@ test canvas-10.7 {check errors from tag expressions} -setup {
     .c create oval 20 260 40 280 -fill bisque -tag [list d "tag with spaces"]
 } -body {
     .c find withtag "d&&\"tag with spaces"
-} -returnCodes error -result {Missing endquote in tag search expression}
+} -returnCodes error -result {missing endquote in tag search expression}
 test canvas-10.8 {check errors from tag expressions} -setup {
     catch {destroy .c}
     canvas .c
@@ -454,7 +454,7 @@ test canvas-10.8 {check errors from tag expressions} -setup {
     .c create oval 20 260 40 280 -fill bisque -tag [list d "tag with spaces"]
 } -returnCodes error -body {
     .c find withtag {a&&"tag with spaces"z}
-} -result {Invalid boolean operator in tag search expression}
+} -result {invalid boolean operator in tag search expression}
 test canvas-10.9 {check errors from tag expressions} -setup {
     catch {destroy .c}
     canvas .c
@@ -462,7 +462,7 @@ test canvas-10.9 {check errors from tag expressions} -setup {
     .c create oval 20 260 40 280 -fill bisque -tag [list d "tag with spaces"]
 } -body {
     .c find withtag {a&&b&c}
-} -returnCodes error -result {Singleton '&' in tag search expression}
+} -returnCodes error -result {singleton '&' in tag search expression}
 test canvas-10.10 {check errors from tag expressions} -setup {
     catch {destroy .c}
     canvas .c
@@ -470,7 +470,7 @@ test canvas-10.10 {check errors from tag expressions} -setup {
     .c create oval 20 260 40 280 -fill bisque -tag [list d "tag with spaces"]
 } -body {
     .c find withtag {a||b|c}
-} -returnCodes error -result {Singleton '|' in tag search expression}
+} -returnCodes error -result {singleton '|' in tag search expression}
 test canvas-10.11 {backward compatility - strange tags that are not expressions} -setup {
     catch {destroy .c}
     canvas .c