more result generation conversion

8 files changed, 308 insertions, 281 deletions

diff --git a/generic/tclInterp.c b/generic/tclInterp.c
index 5bae041..0b0f652 100644
--- a/generic/tclInterp.c
+++ b/generic/tclInterp.c
@@ -1043,18 +1043,18 @@ Tcl_InterpObjCmd(
 	iiPtr = (InterpInfo *) ((Interp *) slaveInterp)->interpInfo;
 	hPtr = Tcl_FindHashEntry(&iiPtr->slave.aliasTable, aliasName);
 	if (hPtr == NULL) {
-	    Tcl_AppendResult(interp, "alias \"", aliasName, "\" in path \"",
-		    Tcl_GetString(objv[2]), "\" not found", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "alias \"%s\" in path \"%s\" not found",
+		    aliasName, Tcl_GetString(objv[2])));
 	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "ALIAS", aliasName,
 		    NULL);
 	    return TCL_ERROR;
 	}
 	aliasPtr = Tcl_GetHashValue(hPtr);
 	if (Tcl_GetInterpPath(interp, aliasPtr->targetInterp) != TCL_OK) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "target interpreter for alias \"",
-		    aliasName, "\" in path \"", Tcl_GetString(objv[2]),
-		    "\" is not my descendant", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "target interpreter for alias \"%s\" in path \"%s\" is "
+		    "not my descendant", aliasName, Tcl_GetString(objv[2])));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP",
 		    "TARGETSHROUDED", NULL);
 	    return TCL_ERROR;
@@ -1234,7 +1234,8 @@ Tcl_GetAlias(
 
     hPtr = Tcl_FindHashEntry(&iiPtr->slave.aliasTable, aliasName);
     if (hPtr == NULL) {
-	Tcl_AppendResult(interp, "alias \"", aliasName, "\" not found", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"alias \"%s\" not found", aliasName));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "ALIAS", aliasName, NULL);
 	return TCL_ERROR;
     }
@@ -1295,7 +1296,8 @@ Tcl_GetAliasObj(
 
     hPtr = Tcl_FindHashEntry(&iiPtr->slave.aliasTable, aliasName);
     if (hPtr == NULL) {
-	Tcl_AppendResult(interp, "alias \"", aliasName, "\" not found", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"alias \"%s\" not found", aliasName));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "ALIAS", aliasName, NULL);
 	return TCL_ERROR;
     }
@@ -1383,9 +1385,9 @@ TclPreventAliasLoop(
 	     * [Bug #641195]
 	     */
 
-	    Tcl_AppendResult(interp, "cannot define or rename alias \"",
-		    Tcl_GetCommandName(cmdInterp, cmd),
-		    "\": interpreter deleted", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "cannot define or rename alias \"%s\": interpreter deleted",
+		    Tcl_GetCommandName(cmdInterp, cmd)));
 	    return TCL_ERROR;
 	}
 	cmdNamePtr = nextAliasPtr->objPtr;
@@ -1398,9 +1400,9 @@ TclPreventAliasLoop(
 	}
 	aliasCmdPtr = (Command *) aliasCmd;
 	if (aliasCmdPtr == cmdPtr) {
-	    Tcl_AppendResult(interp, "cannot define or rename alias \"",
-		    Tcl_GetCommandName(cmdInterp, cmd),
-		    "\": would create a loop", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "cannot define or rename alias \"%s\": would create a loop",
+		    Tcl_GetCommandName(cmdInterp, cmd)));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP",
 		    "ALIASLOOP", NULL);
 	    return TCL_ERROR;
@@ -1621,8 +1623,8 @@ AliasDelete(
     slavePtr = &((InterpInfo *) ((Interp *) slaveInterp)->interpInfo)->slave;
     hPtr = Tcl_FindHashEntry(&slavePtr->aliasTable, TclGetString(namePtr));
     if (hPtr == NULL) {
-	Tcl_AppendResult(interp, "alias \"", TclGetString(namePtr),
-		"\" not found", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"alias \"%s\" not found", TclGetString(namePtr)));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "ALIAS",
 		TclGetString(namePtr), NULL);
 	return TCL_ERROR;
@@ -2220,8 +2222,8 @@ GetInterp(
 	}
     }
     if (searchInterp == NULL) {
-	Tcl_AppendResult(interp, "could not find interpreter \"",
-		TclGetString(pathPtr), "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"could not find interpreter \"%s\"", TclGetString(pathPtr)));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INTERP",
 		TclGetString(pathPtr), NULL);
     }
@@ -2258,8 +2260,8 @@ SlaveBgerror(
 
 	if (TCL_ERROR == TclListObjLength(NULL, objv[0], &length)
 		|| (length < 1)) {
-	    Tcl_AppendResult(interp, "cmdPrefix must be list of length >= 1",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "cmdPrefix must be list of length >= 1", -1));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP",
 		    "BGERRORFORMAT", NULL);
 	    return TCL_ERROR;
@@ -2328,8 +2330,9 @@ SlaveCreate(
     hPtr = Tcl_CreateHashEntry(&masterInfoPtr->master.slaveTable, path,
 	    &isNew);
     if (isNew == 0) {
-	Tcl_AppendResult(interp, "interpreter named \"", path,
-		"\" already exists, cannot create", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"interpreter named \"%s\" already exists, cannot create",
+		path));
 	return NULL;
     }
 
@@ -2862,8 +2865,8 @@ SlaveRecursionLimit(
 
     if (objc) {
 	if (Tcl_IsSafe(interp)) {
-	    Tcl_AppendResult(interp, "permission denied: "
-		    "safe interpreters cannot change recursion limit", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj("permission denied: "
+		    "safe interpreters cannot change recursion limit", -1));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP", "UNSAFE",
 		    NULL);
 	    return TCL_ERROR;
@@ -3322,8 +3325,8 @@ Tcl_LimitCheck(
 	if (iPtr->limit.cmdCount >= iPtr->cmdCount) {
 	    iPtr->limit.exceeded &= ~TCL_LIMIT_COMMANDS;
 	} else if (iPtr->limit.exceeded & TCL_LIMIT_COMMANDS) {
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "command count limit exceeded", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "command count limit exceeded", -1));
 	    Tcl_SetErrorCode(interp, "TCL", "LIMIT", "COMMANDS", NULL);
 	    Tcl_Release(interp);
 	    return TCL_ERROR;
@@ -3348,8 +3351,8 @@ Tcl_LimitCheck(
 		    iPtr->limit.time.usec >= now.usec)) {
 		iPtr->limit.exceeded &= ~TCL_LIMIT_TIME;
 	    } else if (iPtr->limit.exceeded & TCL_LIMIT_TIME) {
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "time limit exceeded", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"time limit exceeded", -1));
 		Tcl_SetErrorCode(interp, "TCL", "LIMIT", "TIME", NULL);
 		Tcl_Release(interp);
 		return TCL_ERROR;
@@ -4355,8 +4358,9 @@ SlaveCommandLimitCmd(
      */
 
     if (interp == slaveInterp) {
-	Tcl_AppendResult(interp,
-		"limits on current interpreter inaccessible", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"limits on current interpreter inaccessible", -1));
+	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP", "SELF", NULL);
 	return TCL_ERROR;
     }
 
@@ -4452,8 +4456,8 @@ SlaveCommandLimitCmd(
 		    return TCL_ERROR;
 		}
 		if (gran < 1) {
-		    Tcl_AppendResult(interp, "granularity must be at "
-			    "least 1", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "granularity must be at least 1", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP",
 			    "BADVALUE", NULL);
 		    return TCL_ERROR;
@@ -4469,8 +4473,8 @@ SlaveCommandLimitCmd(
 		    return TCL_ERROR;
 		}
 		if (limit < 0) {
-		    Tcl_AppendResult(interp, "command limit value must be at "
-			    "least 0", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "command limit value must be at least 0", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP",
 			    "BADVALUE", NULL);
 		    return TCL_ERROR;
@@ -4542,8 +4546,9 @@ SlaveTimeLimitCmd(
      */
 
     if (interp == slaveInterp) {
-	Tcl_AppendResult(interp,
-		"limits on current interpreter inaccessible", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"limits on current interpreter inaccessible", -1));
+	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP", "SELF", NULL);
 	return TCL_ERROR;
     }
 
@@ -4660,8 +4665,8 @@ SlaveTimeLimitCmd(
 		    return TCL_ERROR;
 		}
 		if (gran < 1) {
-		    Tcl_AppendResult(interp, "granularity must be at "
-			    "least 1", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "granularity must be at least 1", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP",
 			    "BADVALUE", NULL);
 		    return TCL_ERROR;
@@ -4677,13 +4682,13 @@ SlaveTimeLimitCmd(
 		    return TCL_ERROR;
 		}
 		if (tmp < 0) {
-		    Tcl_AppendResult(interp, "milliseconds must be at least 0",
-			    NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "milliseconds must be at least 0", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP",
 			    "BADVALUE", NULL);
 		    return TCL_ERROR;
 		}
-		limitMoment.usec = ((long)tmp)*1000;
+		limitMoment.usec = ((long) tmp)*1000;
 		break;
 	    case OPT_SEC:
 		secObj = objv[i+1];
@@ -4695,8 +4700,8 @@ SlaveTimeLimitCmd(
 		    return TCL_ERROR;
 		}
 		if (tmp < 0) {
-		    Tcl_AppendResult(interp, "seconds must be at least 0",
-			    NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "seconds must be at least 0", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP",
 			    "BADVALUE", NULL);
 		    return TCL_ERROR;
@@ -4713,15 +4718,17 @@ SlaveTimeLimitCmd(
 		 */
 
 		if (secObj != NULL && secLen == 0 && milliLen > 0) {
-		    Tcl_AppendResult(interp, "may only set -milliseconds "
-			    "if -seconds is not also being reset", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "may only set -milliseconds if -seconds is not "
+			    "also being reset", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP",
 			    "BADUSAGE", NULL);
 		    return TCL_ERROR;
 		}
 		if (milliLen == 0 && (secObj == NULL || secLen > 0)) {
-		    Tcl_AppendResult(interp, "may only reset -milliseconds "
-			    "if -seconds is also being reset", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "may only reset -milliseconds if -seconds is "
+			    "also being reset", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "INTERP",
 			    "BADUSAGE", NULL);
 		    return TCL_ERROR;
diff --git a/generic/tclLoad.c b/generic/tclLoad.c
index f14cec0..3fead6f 100644
--- a/generic/tclLoad.c
+++ b/generic/tclLoad.c
@@ -224,9 +224,9 @@ Tcl_LoadObjCmd(
 	     * Can't have two different packages loaded from the same file.
 	     */
 
-	    Tcl_AppendResult(interp, "file \"", fullFileName,
-		    "\" is already loaded for package \"",
-		    pkgPtr->packageName, "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "file \"%s\" is already loaded for package \"%s\"",
+		    fullFileName, pkgPtr->packageName));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "LOAD",
 		    "SPLITPERSONALITY", NULL);
 	    code = TCL_ERROR;
@@ -262,8 +262,8 @@ Tcl_LoadObjCmd(
 	 */
 
 	if (fullFileName[0] == 0) {
-	    Tcl_AppendResult(interp, "package \"", packageName,
-		    "\" isn't loaded statically", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "package \"%s\" isn't loaded statically", packageName));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "LOAD", "NOTSTATIC",
 		    NULL);
 	    code = TCL_ERROR;
@@ -320,9 +320,9 @@ Tcl_LoadObjCmd(
 		}
 		if (p == pkgGuess) {
 		    Tcl_DecrRefCount(splitPtr);
-		    Tcl_AppendResult(interp,
-			    "couldn't figure out package name for ",
-			    fullFileName, NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "couldn't figure out package name for %s",
+			    fullFileName));
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "LOAD",
 			    "WHATPACKAGE", NULL);
 		    code = TCL_ERROR;
@@ -417,9 +417,9 @@ Tcl_LoadObjCmd(
 
     if (Tcl_IsSafe(target)) {
 	if (pkgPtr->safeInitProc == NULL) {
-	    Tcl_AppendResult(interp,
-		    "can't use package in a safe interpreter: no ",
-		    pkgPtr->packageName, "_SafeInit procedure", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't use package in a safe interpreter: no"
+		    " %s_SafeInit procedure", pkgPtr->packageName));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "LOAD", "UNSAFE",
 		    NULL);
 	    code = TCL_ERROR;
@@ -428,9 +428,9 @@ Tcl_LoadObjCmd(
 	code = pkgPtr->safeInitProc(target);
     } else {
 	if (pkgPtr->initProc == NULL) {
-	    Tcl_AppendResult(interp,
-		    "can't attach package to interpreter: no ",
-		    pkgPtr->packageName, "_Init procedure", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't attach package to interpreter: no %s_Init procedure",
+		    pkgPtr->packageName));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "LOAD", "ENTRYPOINT",
 		    NULL);
 	    code = TCL_ERROR;
@@ -653,8 +653,9 @@ Tcl_UnloadObjCmd(
 	 * It's an error to try unload a static package.
 	 */
 
-	Tcl_AppendResult(interp, "package \"", packageName,
-		"\" is loaded statically and cannot be unloaded", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"package \"%s\" is loaded statically and cannot be unloaded",
+		packageName));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "UNLOAD", "STATIC",
 		NULL);
 	code = TCL_ERROR;
@@ -665,8 +666,8 @@ Tcl_UnloadObjCmd(
 	 * The DLL pointed by the provided filename has never been loaded.
 	 */
 
-	Tcl_AppendResult(interp, "file \"", fullFileName,
-		"\" has never been loaded", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"file \"%s\" has never been loaded", fullFileName));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "UNLOAD", "NEVERLOADED",
 		NULL);
 	code = TCL_ERROR;
@@ -694,8 +695,9 @@ Tcl_UnloadObjCmd(
 	 * The package has not been loaded in this interpreter.
 	 */
 
-	Tcl_AppendResult(interp, "file \"", fullFileName,
-		"\" has never been loaded in this interpreter", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"file \"%s\" has never been loaded in this interpreter",
+		fullFileName));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "UNLOAD", "NEVERLOADED",
 		NULL);
 	code = TCL_ERROR;
@@ -710,8 +712,9 @@ Tcl_UnloadObjCmd(
 
     if (Tcl_IsSafe(target)) {
 	if (pkgPtr->safeUnloadProc == NULL) {
-	    Tcl_AppendResult(interp, "file \"", fullFileName,
-		    "\" cannot be unloaded under a safe interpreter", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "file \"%s\" cannot be unloaded under a safe interpreter",
+		    fullFileName));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "UNLOAD", "CANNOT",
 		    NULL);
 	    code = TCL_ERROR;
@@ -720,8 +723,9 @@ Tcl_UnloadObjCmd(
 	unloadProc = pkgPtr->safeUnloadProc;
     } else {
 	if (pkgPtr->unloadProc == NULL) {
-	    Tcl_AppendResult(interp, "file \"", fullFileName,
-		    "\" cannot be unloaded under a trusted interpreter", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "file \"%s\" cannot be unloaded under a trusted interpreter",
+		    fullFileName));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "UNLOAD", "CANNOT",
 		    NULL);
 	    code = TCL_ERROR;
@@ -860,8 +864,9 @@ Tcl_UnloadObjCmd(
 	    }
 	}
 #else
-	Tcl_AppendResult(interp, "file \"", fullFileName,
-		"\" cannot be unloaded: unloading disabled", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"file \"%s\" cannot be unloaded: unloading disabled",
+		fullFileName));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "UNLOAD", "DISABLED",
 		NULL);
 	code = TCL_ERROR;
diff --git a/generic/tclNamesp.c b/generic/tclNamesp.c
index 6a241f0..3c93400 100644
--- a/generic/tclNamesp.c
+++ b/generic/tclNamesp.c
@@ -687,9 +687,8 @@ Tcl_CreateNamespace(
 	parentPtr = NULL;
 	simpleName = "";
     } else if (*name == '\0') {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "can't create namespace \"\": "
-		"only global namespace can have empty name", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj("can't create namespace"
+                " \"\": only global namespace can have empty name", -1));
         Tcl_SetErrorCode(interp, "TCL", "OPERATION", "NAMESPACE",
                 "CREATEGLOBAL", NULL);
 	return NULL;
@@ -725,8 +724,8 @@ Tcl_CreateNamespace(
 	    Tcl_FindHashEntry(parentPtr->childTablePtr, simpleName) != NULL
 #endif
 	) {
-	    Tcl_AppendResult(interp, "can't create namespace \"", name,
-		    "\": already exists", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "can't create namespace \"%s\": already exists", name));
             Tcl_SetErrorCode(interp, "TCL", "OPERATION", "NAMESPACE",
                     "CREATEEXISTING", NULL);
 	    return NULL;
@@ -1336,8 +1335,8 @@ Tcl_Export(
 	    &exportNsPtr, &dummyPtr, &dummyPtr, &simplePattern);
 
     if ((exportNsPtr != nsPtr) || (strcmp(pattern, simplePattern) != 0)) {
-	Tcl_AppendResult(interp, "invalid export pattern \"", pattern,
-		"\": pattern can't specify a namespace", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf("invalid export pattern"
+                " \"%s\": pattern can't specify a namespace", pattern));
         Tcl_SetErrorCode(interp, "TCL", "EXPORT", "INVALID", NULL);
 	return TCL_ERROR;
     }
@@ -1551,21 +1550,21 @@ Tcl_Import(
 	    &importNsPtr, &dummyPtr, &dummyPtr, &simplePattern);
 
     if (importNsPtr == NULL) {
-	Tcl_AppendResult(interp, "unknown namespace in import pattern \"",
-		pattern, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                "unknown namespace in import pattern \"%s\"", pattern));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "NAMESPACE", pattern, NULL);
 	return TCL_ERROR;
     }
     if (importNsPtr == nsPtr) {
 	if (pattern == simplePattern) {
-	    Tcl_AppendResult(interp,
-		    "no namespace specified in import pattern \"", pattern,
-		    "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "no namespace specified in import pattern \"%s\"",
+                    pattern));
             Tcl_SetErrorCode(interp, "TCL", "IMPORT", "ORIGIN", NULL);
 	} else {
-	    Tcl_AppendResult(interp, "import pattern \"", pattern,
-		    "\" tries to import from namespace \"",
-		    importNsPtr->name, "\" into itself", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "import pattern \"%s\" tries to import from namespace"
+                    " \"%s\" into itself", pattern, importNsPtr->name));
             Tcl_SetErrorCode(interp, "TCL", "IMPORT", "SELF", NULL);
 	}
 	return TCL_ERROR;
@@ -1684,9 +1683,10 @@ DoImport(
 		dataPtr = linkCmd->objClientData;
 		linkCmd = dataPtr->realCmdPtr;
 		if (overwrite == linkCmd) {
-		    Tcl_AppendResult(interp, "import pattern \"", pattern,
-			    "\" would create a loop containing command \"",
-			    Tcl_DStringValue(&ds), "\"", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                            "import pattern \"%s\" would create a loop"
+                            " containing command \"%s\"",
+                            pattern, Tcl_DStringValue(&ds)));
 		    Tcl_DStringFree(&ds);
                     Tcl_SetErrorCode(interp, "TCL", "IMPORT", "LOOP", NULL);
 		    return TCL_ERROR;
@@ -1726,8 +1726,8 @@ DoImport(
 		return TCL_OK;
 	    }
 	}
-	Tcl_AppendResult(interp, "can't import command \"", cmdName,
-		"\": already exists", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                "can't import command \"%s\": already exists", cmdName));
         Tcl_SetErrorCode(interp, "TCL", "IMPORT", "OVERWRITE", NULL);
 	return TCL_ERROR;
     }
@@ -1796,9 +1796,9 @@ Tcl_ForgetImport(
 	    &sourceNsPtr, &dummyPtr, &dummyPtr, &simplePattern);
 
     if (sourceNsPtr == NULL) {
-	Tcl_AppendResult(interp,
-		"unknown namespace in namespace forget pattern \"",
-		pattern, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"unknown namespace in namespace forget pattern \"%s\"",
+		pattern));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "NAMESPACE", pattern, NULL);
 	return TCL_ERROR;
     }
@@ -2402,8 +2402,8 @@ Tcl_FindNamespace(
     }
 
     if (flags & TCL_LEAVE_ERR_MSG) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "unknown namespace \"", name, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                "unknown namespace \"%s\"", name));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "NAMESPACE", name, NULL);
     }
     return NULL;
@@ -2589,8 +2589,8 @@ Tcl_FindCommand(
     }
 
     if (flags & TCL_LEAVE_ERR_MSG) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "unknown command \"", name, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                "unknown command \"%s\"", name));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "COMMAND", name, NULL);
     }
     return NULL;
@@ -3170,9 +3170,9 @@ NamespaceDeleteCmd(
 	namespacePtr = Tcl_FindNamespace(interp, name, NULL, /*flags*/ 0);
 	if ((namespacePtr == NULL)
 		|| (((Namespace *) namespacePtr)->flags & NS_KILLED)) {
-	    Tcl_AppendResult(interp, "unknown namespace \"",
-		    TclGetString(objv[i]),
-		    "\" in namespace delete command", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "unknown namespace \"%s\" in namespace delete command",
+		    TclGetString(objv[i])));
 	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "NAMESPACE",
 		    TclGetString(objv[i]), NULL);
 	    return TCL_ERROR;
@@ -3834,8 +3834,8 @@ NamespaceOriginCmd(
 
     command = Tcl_GetCommandFromObj(interp, objv[1]);
     if (command == NULL) {
-	Tcl_AppendResult(interp, "invalid command name \"",
-		TclGetString(objv[1]), "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                "invalid command name \"%s\"", TclGetString(objv[1])));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "COMMAND",
 		TclGetString(objv[1]), NULL);
 	return TCL_ERROR;
diff --git a/generic/tclObj.c b/generic/tclObj.c
index 099b67d..74cb29e 100644
--- a/generic/tclObj.c
+++ b/generic/tclObj.c
@@ -4462,11 +4462,8 @@ Tcl_RepresentationCmd(
     int objc,
     Tcl_Obj *const objv[])
 {
-    char refcountBuffer[TCL_INTEGER_SPACE+1];
-    char objPtrBuffer[TCL_INTEGER_SPACE+3];
-    char internalRepBuffer[2*(TCL_INTEGER_SPACE+2)+2];
-#define TCLOBJ_TRUNCATE_STRINGREP 16
-    char stringRepBuffer[TCLOBJ_TRUNCATE_STRINGREP+1];
+    char ptrBuffer[2*TCL_INTEGER_SPACE+6];
+    Tcl_Obj *descObj;
 
     if (objc != 2) {
 	Tcl_WrongNumArgs(interp, 1, objv, "value");
@@ -4479,27 +4476,30 @@ Tcl_RepresentationCmd(
      * "1872361827361287"
      */
 
-    sprintf(refcountBuffer, "%d", objv[1]->refCount);
-    sprintf(objPtrBuffer, "%p", (void *)objv[1]);
-    Tcl_AppendResult(interp, "value is a ", objv[1]->typePtr ?
-	    objv[1]->typePtr->name : "pure string", " with a refcount of ",
-	    refcountBuffer, ", object pointer at ", objPtrBuffer, NULL);
+    sprintf(ptrBuffer, "%p", (void *) objv[1]);
+    descObj = Tcl_ObjPrintf("value is a %s with a refcount of %d,"
+            " object pointer at %s",
+            objv[1]->typePtr ? objv[1]->typePtr->name : "pure string",
+	    objv[1]->refCount, ptrBuffer);
+
     if (objv[1]->typePtr) {
-	sprintf(internalRepBuffer, "%p:%p",
-		(void *)objv[1]->internalRep.twoPtrValue.ptr1,
-		(void *)objv[1]->internalRep.twoPtrValue.ptr2);
-	Tcl_AppendResult(interp, ", internal representation ",
-		internalRepBuffer, NULL);
+	sprintf(ptrBuffer, "%p:%p",
+		(void *) objv[1]->internalRep.twoPtrValue.ptr1,
+		(void *) objv[1]->internalRep.twoPtrValue.ptr2);
+	Tcl_AppendPrintfToObj(descObj, ", internal representation %s",
+		ptrBuffer);
     }
+
     if (objv[1]->bytes) {
-	strncpy(stringRepBuffer, objv[1]->bytes, TCLOBJ_TRUNCATE_STRINGREP);
-	stringRepBuffer[TCLOBJ_TRUNCATE_STRINGREP] = 0;
-	Tcl_AppendResult(interp, ", string representation \"",
-		stringRepBuffer, objv[1]->length > TCLOBJ_TRUNCATE_STRINGREP ?
-		"\"..." : "\".", NULL);
+        Tcl_AppendToObj(descObj, ", string representation \"", -1);
+	Tcl_AppendLimitedToObj(descObj, objv[1]->bytes, objv[1]->length,
+                16, "...");
+	Tcl_AppendToObj(descObj, "\"", -1);
     } else {
-	Tcl_AppendResult(interp, ", no string representation.", NULL);
+	Tcl_AppendToObj(descObj, ", no string representation", -1);
     }
+
+    Tcl_SetObjResult(interp, descObj);
     return TCL_OK;
 }
 
diff --git a/generic/tclPipe.c b/generic/tclPipe.c
index 56a1846..83fb818 100644
--- a/generic/tclPipe.c
+++ b/generic/tclPipe.c
@@ -106,9 +106,10 @@ FileForRedirect(
 	    if (msg) {
 		Tcl_SetObjResult(interp, msg);
 	    } else {
-		Tcl_AppendResult(interp, "channel \"",
-			Tcl_GetChannelName(chan), "\" wasn't opened for ",
-			((writing) ? "writing" : "reading"), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"channel \"%s\" wasn't opened for %s",
+			Tcl_GetChannelName(chan),
+			((writing) ? "writing" : "reading")));
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "EXEC",
 			"BADCHAN", NULL);
 	    }
@@ -141,9 +142,10 @@ FileForRedirect(
 	file = TclpOpenFile(name, flags);
 	Tcl_DStringFree(&nameString);
 	if (file == NULL) {
-	    Tcl_AppendResult(interp, "couldn't ",
-		    ((writing) ? "write" : "read"), " file \"", spec, "\": ",
-		    Tcl_PosixError(interp), NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "couldn't %s file \"%s\": %s",
+		    (writing ? "write" : "read"), spec,
+		    Tcl_PosixError(interp)));
 	    return NULL;
 	}
 	*closePtr = 1;
@@ -151,8 +153,8 @@ FileForRedirect(
     return file;
 
   badLastArg:
-    Tcl_AppendResult(interp, "can't specify \"", arg,
-	    "\" as last word in command", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "can't specify \"%s\" as last word in command", arg));
     Tcl_SetErrorCode(interp, "TCL", "OPERATION", "EXEC", "SYNTAX", NULL);
     return NULL;
 }
@@ -304,8 +306,8 @@ TclCleanupChildren(
 		    msg =
 			"child process lost (is SIGCHLD ignored or trapped?)";
 		}
-		Tcl_AppendResult(interp, "error waiting for process to exit: ",
-			msg, NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"error waiting for process to exit: %s", msg));
 	    }
 	    continue;
 	}
@@ -335,16 +337,17 @@ TclCleanupChildren(
 		    p = Tcl_SignalMsg(WTERMSIG(waitStatus));
 		    Tcl_SetErrorCode(interp, "CHILDKILLED", msg1,
 			    Tcl_SignalId(WTERMSIG(waitStatus)), p, NULL);
-		    Tcl_AppendResult(interp, "child killed: ", p, "\n", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "child killed: %s\n", p));
 		} else if (WIFSTOPPED(waitStatus)) {
 		    p = Tcl_SignalMsg(WSTOPSIG(waitStatus));
 		    Tcl_SetErrorCode(interp, "CHILDSUSP", msg1,
 			    Tcl_SignalId(WSTOPSIG(waitStatus)), p, NULL);
-		    Tcl_AppendResult(interp, "child suspended: ", p, "\n",
-			    NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "child suspended: %s\n", p));
 		} else {
-		    Tcl_AppendResult(interp,
-			    "child wait status didn't make sense\n", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "child wait status didn't make sense\n", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "EXEC",
 			    "ODDWAITRESULT", msg1, NULL);
 		}
@@ -374,8 +377,9 @@ TclCleanupChildren(
 		result = TCL_ERROR;
 		Tcl_DecrRefCount(objPtr);
 		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "error reading stderr output file: ",
-			Tcl_PosixError(interp), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"error reading stderr output file: %s",
+			Tcl_PosixError(interp)));
 	    } else if (count > 0) {
 		anyErrorInfo = 1;
 		Tcl_SetObjResult(interp, objPtr);
@@ -393,7 +397,8 @@ TclCleanupChildren(
      */
 
     if ((abnormalExit != 0) && (anyErrorInfo == 0) && (interp != NULL)) {
-	Tcl_AppendResult(interp, "child process exited abnormally", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"child process exited abnormally", -1));
     }
     return result;
 }
@@ -570,8 +575,9 @@ TclCreatePipeline(
 		if (*inputLiteral == '\0') {
 		    inputLiteral = ((i + 1) == argc) ? NULL : argv[i + 1];
 		    if (inputLiteral == NULL) {
-			Tcl_AppendResult(interp, "can't specify \"", argv[i],
-				"\" as last word in command", NULL);
+			Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+				"can't specify \"%s\" as last word in command",
+				argv[i]));
 			Tcl_SetErrorCode(interp, "TCL", "OPERATION", "EXEC",
 				"PIPESYNTAX", NULL);
 			goto error;
@@ -680,8 +686,9 @@ TclCreatePipeline(
 		 */
 
 		if (i != argc-1) {
-		    Tcl_AppendResult(interp, "must specify \"", argv[i],
-			    "\" as last word in command", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "must specify \"%s\" as last word in command",
+			    argv[i]));
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "EXEC",
 			    "PIPESYNTAX", NULL);
 		    goto error;
@@ -739,9 +746,9 @@ TclCreatePipeline(
 
 	    inputFile = TclpCreateTempFile(inputLiteral);
 	    if (inputFile == NULL) {
-		Tcl_AppendResult(interp,
-			"couldn't create input file for command: ",
-			Tcl_PosixError(interp), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"couldn't create input file for command: %s",
+			Tcl_PosixError(interp)));
 		goto error;
 	    }
 	    inputClose = 1;
@@ -752,9 +759,9 @@ TclCreatePipeline(
 	     */
 
 	    if (TclpCreatePipe(&inputFile, inPipePtr) == 0) {
-		Tcl_AppendResult(interp,
-			"couldn't create input pipe for command: ",
-			Tcl_PosixError(interp), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"couldn't create input pipe for command: %s",
+			Tcl_PosixError(interp)));
 		goto error;
 	    }
 	    inputClose = 1;
@@ -781,9 +788,9 @@ TclCreatePipeline(
 	     */
 
 	    if (TclpCreatePipe(outPipePtr, &outputFile) == 0) {
-		Tcl_AppendResult(interp,
-			"couldn't create output pipe for command: ",
-			Tcl_PosixError(interp), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"couldn't create output pipe for command: %s",
+			Tcl_PosixError(interp)));
 		goto error;
 	    }
 	    outputClose = 1;
@@ -821,9 +828,9 @@ TclCreatePipeline(
 
 	    errorFile = TclpCreateTempFile(NULL);
 	    if (errorFile == NULL) {
-		Tcl_AppendResult(interp,
-			"couldn't create error file for command: ",
-			Tcl_PosixError(interp), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"couldn't create error file for command: %s",
+			Tcl_PosixError(interp)));
 		goto error;
 	    }
 	    *errFilePtr = errorFile;
@@ -894,8 +901,8 @@ TclCreatePipeline(
 	} else {
 	    argv[lastArg] = NULL;
 	    if (TclpCreatePipe(&pipeIn, &curOutFile) == 0) {
-		Tcl_AppendResult(interp, "couldn't create pipe: ",
-			Tcl_PosixError(interp), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"couldn't create pipe: %s", Tcl_PosixError(interp)));
 		goto error;
 	    }
 	}
@@ -1074,15 +1081,17 @@ Tcl_OpenCommandChannel(
 
     if (flags & TCL_ENFORCE_MODE) {
 	if ((flags & TCL_STDOUT) && (outPipe == NULL)) {
-	    Tcl_AppendResult(interp, "can't read output from command:"
-		    " standard output was redirected", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't read output from command:"
+		    " standard output was redirected", -1));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "EXEC",
 		    "BADREDIRECT", NULL);
 	    goto error;
 	}
 	if ((flags & TCL_STDIN) && (inPipe == NULL)) {
-	    Tcl_AppendResult(interp, "can't write input to command:"
-		    " standard input was redirected", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "can't write input to command:"
+		    " standard input was redirected", -1));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "EXEC",
 		    "BADREDIRECT", NULL);
 	    goto error;
@@ -1093,8 +1102,8 @@ Tcl_OpenCommandChannel(
 	    numPids, pidPtr);
 
     if (channel == NULL) {
-	Tcl_AppendResult(interp, "pipe for command could not be created",
-		NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"pipe for command could not be created", -1));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "EXEC", "NOPIPE", NULL);
 	goto error;
     }
diff --git a/generic/tclPkg.c b/generic/tclPkg.c
index 730efec..9b6e942 100644
--- a/generic/tclPkg.c
+++ b/generic/tclPkg.c
@@ -154,8 +154,9 @@ Tcl_PkgProvideEx(
 	}
 	return TCL_OK;
     }
-    Tcl_AppendResult(interp, "conflicting versions provided for package \"",
-	    name, "\": ", pkgPtr->version, ", then ", version, NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "conflicting versions provided for package \"%s\": %s, then %s",
+	    name, pkgPtr->version, version));
     Tcl_SetErrorCode(interp, "TCL", "PACKAGE", "VERSIONCONFLICT", NULL);
     return TCL_ERROR;
 }
@@ -284,9 +285,9 @@ Tcl_PkgRequireEx(
 	 */
 
 	tclEmptyStringRep = &tclEmptyString;
-	Tcl_AppendResult(interp, "Cannot load package \"", name,
-		"\" in standalone executable: This package is not "
-		"compiled with stub support", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"Cannot load package \"%s\" in standalone executable:"
+		" This package is not compiled with stub support", name));
 	Tcl_SetErrorCode(interp, "TCL", "PACKAGE", "UNSTUBBED", NULL);
 	return NULL;
     }
@@ -374,9 +375,10 @@ PkgRequireCore(
 	 */
 
 	if (pkgPtr->clientData != NULL) {
-	    Tcl_AppendResult(interp, "circular package dependency: "
-		    "attempt to provide ", name, " ",
-		    (char *) pkgPtr->clientData, " requires ", name, NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "circular package dependency:"
+		    " attempt to provide %s %s requires %s", 
+		    name, (char *) pkgPtr->clientData, name));
 	    AddRequirementsToResult(interp, reqc, reqv);
 	    Tcl_SetErrorCode(interp, "TCL", "PACKAGE", "CIRCULARITY", NULL);
 	    return NULL;
@@ -494,10 +496,10 @@ PkgRequireCore(
 		Tcl_ResetResult(interp);
 		if (pkgPtr->version == NULL) {
 		    code = TCL_ERROR;
-		    Tcl_AppendResult(interp, "attempt to provide package ",
-			    name, " ", versionToProvide,
-			    " failed: no version of package ", name,
-			    " provided", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "attempt to provide package %s %s failed:"
+			    " no version of package %s provided",
+			    name, versionToProvide, name));
 		    Tcl_SetErrorCode(interp, "TCL", "PACKAGE", "UNPROVIDED",
 			    NULL);
 		} else {
@@ -517,11 +519,11 @@ PkgRequireCore(
 			ckfree(vi);
 			if (res != 0) {
 			    code = TCL_ERROR;
-			    Tcl_AppendResult(interp,
-				    "attempt to provide package ", name, " ",
-				    versionToProvide, " failed: package ",
-				    name, " ", pkgPtr->version,
-				    " provided instead", NULL);
+			    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+				    "attempt to provide package %s %s failed:"
+				    " package %s %s provided instead",
+				    name, versionToProvide,
+				    name, pkgPtr->version));
 			    Tcl_SetErrorCode(interp, "TCL", "PACKAGE",
 				    "WRONGPROVIDE", NULL);
 			}
@@ -530,10 +532,10 @@ PkgRequireCore(
 	    } else if (code != TCL_ERROR) {
 		Tcl_Obj *codePtr = Tcl_NewIntObj(code);
 
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "attempt to provide package ", name,
-			" ", versionToProvide, " failed: bad return code: ",
-			TclGetString(codePtr), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"attempt to provide package %s %s failed:"
+			" bad return code: %s",
+			name, versionToProvide, TclGetString(codePtr)));
 		Tcl_SetErrorCode(interp, "TCL", "PACKAGE", "BADRESULT", NULL);
 		TclDecrRefCount(codePtr);
 		code = TCL_ERROR;
@@ -591,13 +593,9 @@ PkgRequireCore(
 	    Tcl_DStringFree(&command);
 
 	    if ((code != TCL_OK) && (code != TCL_ERROR)) {
-		Tcl_Obj *codePtr = Tcl_NewIntObj(code);
-
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "bad return code: ",
-			TclGetString(codePtr), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"bad return code: %d", code));
 		Tcl_SetErrorCode(interp, "TCL", "PACKAGE", "BADRESULT", NULL);
-		Tcl_DecrRefCount(codePtr);
 		code = TCL_ERROR;
 	    }
 	    if (code == TCL_ERROR) {
@@ -610,7 +608,8 @@ PkgRequireCore(
     }
 
     if (pkgPtr->version == NULL) {
-	Tcl_AppendResult(interp, "can't find package ", name, NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't find package %s", name));
 	Tcl_SetErrorCode(interp, "TCL", "PACKAGE", "UNFOUND", NULL);
 	AddRequirementsToResult(interp, reqc, reqv);
 	return NULL;
@@ -628,8 +627,9 @@ PkgRequireCore(
 	ckfree(pkgVersionI);
 
 	if (!satisfies) {
-	    Tcl_AppendResult(interp, "version conflict for package \"", name,
-		    "\": have ", pkgPtr->version, ", need", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "version conflict for package \"%s\": have %s, need",
+		    name, pkgPtr->version));
 	    Tcl_SetErrorCode(interp, "TCL", "PACKAGE", "VERSIONCONFLICT",
 		    NULL);
 	    AddRequirementsToResult(interp, reqc, reqv);
@@ -721,10 +721,11 @@ Tcl_PkgPresentEx(
     }
 
     if (version != NULL) {
-	Tcl_AppendResult(interp, "package ", name, " ", version,
-		" is not present", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"package %s %s is not present", name, version));
     } else {
-	Tcl_AppendResult(interp, "package ", name, " is not present", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"package %s is not present", name));
     }
     Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "PACKAGE", name, NULL);
     return NULL;
@@ -1354,8 +1355,8 @@ CheckVersionAndConvert(
 
   error:
     ckfree(ibuf);
-    Tcl_AppendResult(interp, "expected version number but got \"", string,
-	    "\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "expected version number but got \"%s\"", string));
     Tcl_SetErrorCode(interp, "TCL", "VALUE", "VERSION", NULL);
     return TCL_ERROR;
 }
@@ -1617,8 +1618,8 @@ CheckRequirement(
 	 * More dashes found after the first. This is wrong.
 	 */
 
-	Tcl_AppendResult(interp, "expected versionMin-versionMax but got \"",
-		string, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"expected versionMin-versionMax but got \"%s\"", string));
 	Tcl_SetErrorCode(interp, "TCL", "VALUE", "VERSIONRANGE", NULL);
 	return TCL_ERROR;
     }
@@ -1670,19 +1671,17 @@ AddRequirementsToResult(
     Tcl_Obj *const reqv[])	/* 0 means to use the latest version
 				 * available. */
 {
-    if (reqc > 0) {
-	int i;
+    Tcl_Obj *result = Tcl_GetObjResult(interp);
+    int i, length;
 
-	for (i = 0; i < reqc; i++) {
-	    int length;
-	    const char *v = Tcl_GetStringFromObj(reqv[i], &length);
+    for (i = 0; i < reqc; i++) {
+	const char *v = Tcl_GetStringFromObj(reqv[i], &length);
 
-	    if ((length & 0x1) && (v[length/2] == '-')
-		    && (strncmp(v, v+((length+1)/2), length/2) == 0)) {
-		Tcl_AppendResult(interp, " exactly ", v+((length+1)/2), NULL);
-	    } else {
-		Tcl_AppendResult(interp, " ", v, NULL);
-	    }
+	if ((length & 0x1) && (v[length/2] == '-')
+		&& (strncmp(v, v+((length+1)/2), length/2) == 0)) {
+	    Tcl_AppendPrintfToObj(result, " exactly %s", v+((length+1)/2));
+	} else {
+	    Tcl_AppendPrintfToObj(result, " %s", v);
 	}
     }
 }
@@ -1711,9 +1710,9 @@ AddRequirementsToDString(
     Tcl_Obj *const reqv[])	/* 0 means to use the latest version
 				 * available. */
 {
-    if (reqc > 0) {
-	int i;
+    int i;
 
+    if (reqc > 0) {
 	for (i = 0; i < reqc; i++) {
 	    TclDStringAppendLiteral(dsPtr, " ");
 	    TclDStringAppendObj(dsPtr, reqv[i]);
diff --git a/generic/tclProc.c b/generic/tclProc.c
index 537008c..933e7d2 100644
--- a/generic/tclProc.c
+++ b/generic/tclProc.c
@@ -152,22 +152,24 @@ Tcl_ProcObjCmd(
 	    &nsPtr, &altNsPtr, &cxtNsPtr, &procName);
 
     if (nsPtr == NULL) {
-	Tcl_AppendResult(interp, "can't create procedure \"", fullName,
-		"\": unknown namespace", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't create procedure \"%s\": unknown namespace",
+		fullName));
 	Tcl_SetErrorCode(interp, "TCL", "VALUE", "COMMAND", NULL);
 	return TCL_ERROR;
     }
     if (procName == NULL) {
-	Tcl_AppendResult(interp, "can't create procedure \"", fullName,
-		"\": bad procedure name", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't create procedure \"%s\": bad procedure name",
+		fullName));
 	Tcl_SetErrorCode(interp, "TCL", "VALUE", "COMMAND", NULL);
 	return TCL_ERROR;
     }
     if ((nsPtr != iPtr->globalNsPtr)
 	    && (procName != NULL) && (procName[0] == ':')) {
-	Tcl_AppendResult(interp, "can't create procedure \"", procName,
-		"\" in non-global namespace with name starting with \":\"",
-		NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't create procedure \"%s\" in non-global namespace with"
+		" name starting with \":\"", procName));
 	Tcl_SetErrorCode(interp, "TCL", "VALUE", "COMMAND", NULL);
 	return TCL_ERROR;
     }
@@ -518,16 +520,17 @@ TclCreateProc(
 	}
 	if (fieldCount > 2) {
 	    ckfree(fieldValues);
-	    Tcl_AppendResult(interp,
-		    "too many fields in argument specifier \"",
-		    argArray[i], "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "too many fields in argument specifier \"%s\"",
+		    argArray[i]));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "PROC",
 		    "FORMALARGUMENTFORMAT", NULL);
 	    goto procError;
 	}
 	if ((fieldCount == 0) || (*fieldValues[0] == 0)) {
 	    ckfree(fieldValues);
-	    Tcl_AppendResult(interp, "argument with no name", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "argument with no name", -1));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "PROC",
 		    "FORMALARGUMENTFORMAT", NULL);
 	    goto procError;
@@ -553,16 +556,18 @@ TclCreateProc(
 		} while (*q != '\0');
 		q--;
 		if (*q == ')') {	/* We have an array element. */
-		    Tcl_AppendResult(interp, "formal parameter \"",
-			    fieldValues[0], "\" is an array element", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "formal parameter \"%s\" is an array element",
+			    fieldValues[0]));
 		    ckfree(fieldValues);
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "PROC",
 			    "FORMALARGUMENTFORMAT", NULL);
 		    goto procError;
 		}
 	    } else if ((*p == ':') && (*(p+1) == ':')) {
-		Tcl_AppendResult(interp, "formal parameter \"",
-			fieldValues[0], "\" is not a simple name", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"formal parameter \"%s\" is not a simple name",
+			fieldValues[0]));
 		ckfree(fieldValues);
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "PROC",
 			"FORMALARGUMENTFORMAT", NULL);
@@ -767,8 +772,7 @@ TclGetFrame(
     return result;
 
   levelError:
-    Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp, "bad level \"", name, "\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf("bad level \"%s\"", name));
     Tcl_SetErrorCode(interp, "TCL", "VALUE", "STACKLEVEL", NULL);
     return -1;
 }
@@ -900,8 +904,7 @@ TclObjGetFrame(
     return result;
 
   levelError:
-    Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp, "bad level \"", name, "\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf("bad level \"%s\"", name));
     Tcl_SetErrorCode(interp, "TCL", "VALUE", "STACKLEVEL", NULL);
     return -1;
 }
@@ -1879,10 +1882,9 @@ InterpProcNR2(
 	 * transform to an error now.
 	 */
 
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "invoked \"",
-		((result == TCL_BREAK) ? "break" : "continue"),
-		"\" outside of a loop", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"invoked \"%s\" outside of a loop",
+		((result == TCL_BREAK) ? "break" : "continue")));
 	Tcl_SetErrorCode(interp, "TCL", "RESULT", "UNEXPECTED", NULL);
 	result = TCL_ERROR;
 
@@ -1999,8 +2001,8 @@ TclProcCompileProc(
 
 	if (codePtr->flags & TCL_BYTECODE_PRECOMPILED) {
 	    if ((Interp *) *codePtr->interpHandle != iPtr) {
-		Tcl_AppendResult(interp,
-			"a precompiled script jumped interps", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"a precompiled script jumped interps", -1));
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "PROC",
 			"CROSSINTERPBYTECODE", NULL);
 		return TCL_ERROR;
@@ -2932,8 +2934,8 @@ Tcl_DisassembleObjCmd(
 
 	procPtr = TclFindProc((Interp *) interp, TclGetString(objv[2]));
 	if (procPtr == NULL) {
-	    Tcl_AppendResult(interp, "\"", TclGetString(objv[2]),
-		    "\" isn't a procedure", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "\"%s\" isn't a procedure", TclGetString(objv[2])));
 	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "PROC",
 		    TclGetString(objv[2]), NULL);
 	    return TCL_ERROR;
@@ -2982,8 +2984,8 @@ Tcl_DisassembleObjCmd(
 	    return TCL_ERROR;
 	}
 	if (oPtr->classPtr == NULL) {
-	    Tcl_AppendResult(interp, "\"", TclGetString(objv[2]),
-		    "\" is not a class", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "\"%s\" is not a class", TclGetString(objv[2])));
 	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "CLASS",
 		    TclGetString(objv[2]), NULL);
 	    return TCL_ERROR;
@@ -3017,16 +3019,16 @@ Tcl_DisassembleObjCmd(
     methodBody:
 	if (hPtr == NULL) {
 	unknownMethod:
-	    Tcl_AppendResult(interp, "unknown method \"",
-		    TclGetString(objv[3]), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "unknown method \"%s\"", TclGetString(objv[3])));
 	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "METHOD",
 		    TclGetString(objv[3]), NULL);
 	    return TCL_ERROR;
 	}
 	procPtr = TclOOGetProcFromMethod(Tcl_GetHashValue(hPtr));
 	if (procPtr == NULL) {
-	    Tcl_AppendResult(interp,
-		    "body not available for this kind of method", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "body not available for this kind of method", -1));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "DISASSEMBLE",
 		    "METHODTYPE", NULL);
 	    return TCL_ERROR;
@@ -3061,7 +3063,8 @@ Tcl_DisassembleObjCmd(
 
     if (((ByteCode *) codeObjPtr->internalRep.otherValuePtr)->flags
 	    & TCL_BYTECODE_PRECOMPILED) {
-	Tcl_AppendResult(interp,"may not disassemble prebuilt bytecode",NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"may not disassemble prebuilt bytecode", -1));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "DISASSEMBLE",
 		"BYTECODE", NULL);
 	return TCL_ERROR;
diff --git a/generic/tclZlib.c b/generic/tclZlib.c
index 8a57a91..544fb6e 100644
--- a/generic/tclZlib.c
+++ b/generic/tclZlib.c
@@ -1896,7 +1896,7 @@ ZlibCmd(
 	    format = TCL_ZLIB_FORMAT_GZIP;
 	    break;
 	default:
-	    Tcl_AppendResult(interp, "IMPOSSIBLE", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj("impossible!", -1));
 	    return TCL_ERROR;
 	}
 
@@ -1910,16 +1910,16 @@ ZlibCmd(
 	 */
 
 	if (mode == TCL_ZLIB_STREAM_DEFLATE && !(chanMode & TCL_WRITABLE)) {
-	    Tcl_AppendResult(interp,
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		    "compression may only be applied to writable channels",
-		    NULL);
+		    -1));
 	    Tcl_SetErrorCode(interp, "TCL", "ZIP", "UNWRITABLE", NULL);
 	    return TCL_ERROR;
 	}
 	if (mode == TCL_ZLIB_STREAM_INFLATE && !(chanMode & TCL_READABLE)) {
-	    Tcl_AppendResult(interp,
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		    "decompression may only be applied to readable channels",
-		    NULL);
+		    -1));
 	    Tcl_SetErrorCode(interp, "TCL", "ZIP", "UNREADABLE", NULL);
 	    return TCL_ERROR;
 	}
@@ -1937,8 +1937,8 @@ ZlibCmd(
 	    switch ((enum pushOptions) option) {
 	    case poHeader:
 		if (++i > objc-1) {
-		    Tcl_AppendResult(interp,
-			    "value missing for -header option", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "value missing for -header option", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "ZIP", "NOVAL", NULL);
 		    return TCL_ERROR;
 		}
@@ -1950,8 +1950,8 @@ ZlibCmd(
 		break;
 	    case poLevel:
 		if (++i > objc-1) {
-		    Tcl_AppendResult(interp,
-			    "value missing for -level option", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "value missing for -level option", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "ZIP", "NOVAL", NULL);
 		    return TCL_ERROR;
 		}
@@ -1967,8 +1967,8 @@ ZlibCmd(
 		break;
 	    case poLimit:
 		if (++i > objc-1) {
-		    Tcl_AppendResult(interp,
-			    "value missing for -limit option", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "value missing for -limit option", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "ZIP", "NOVAL", NULL);
 		    return TCL_ERROR;
 		}
@@ -1996,14 +1996,15 @@ ZlibCmd(
     return TCL_ERROR;
 
   badLevel:
-    Tcl_AppendResult(interp, "level must be 0 to 9", NULL);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj("level must be 0 to 9", -1));
     Tcl_SetErrorCode(interp, "TCL", "VALUE", "COMPRESSIONLEVEL", NULL);
     if (extraInfoStr) {
 	Tcl_AddErrorInfo(interp, extraInfoStr);
     }
     return TCL_ERROR;
   badBuffer:
-    Tcl_AppendResult(interp, "buffer size must be 32 to 65536", NULL);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+	    "buffer size must be 32 to 65536", -1));
     Tcl_SetErrorCode(interp, "TCL", "VALUE", "BUFFERSIZE", NULL);
     return TCL_ERROR;
 }
@@ -2086,9 +2087,9 @@ ZlibStreamCmd(
 		break;
 	    case ao_buffer: /* -buffer */
 		if (i == objc-2) {
-		    Tcl_AppendResult(interp, "\"-buffer\" option must be "
-			    "followed by integer decompression buffersize",
-			    NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "\"-buffer\" option must be followed by integer"
+			    " decompression buffersize", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "ZIP", "NOVAL", NULL);
 		    return TCL_ERROR;
 		}
@@ -2097,8 +2098,8 @@ ZlibStreamCmd(
 		    return TCL_ERROR;
 		}
 		if (buffersize < 1 || buffersize > 65536) {
-		    Tcl_AppendResult(interp,
-			    "buffer size must be 32 to 65536", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "buffer size must be 32 to 65536", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "VALUE", "BUFFERSIZE",
 			    NULL);
 		    return TCL_ERROR;
@@ -2106,8 +2107,9 @@ ZlibStreamCmd(
 	    }
 
 	    if (flush == -2) {
-		Tcl_AppendResult(interp, "\"-flush\", \"-fullflush\" and "
-			"\"-finalize\" options are mutually exclusive", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"\"-flush\", \"-fullflush\" and \"-finalize\" options"
+			" are mutually exclusive", -1));
 		Tcl_SetErrorCode(interp, "TCL", "ZIP", "EXCLUSIVE", NULL);
 		return TCL_ERROR;
 	    }
@@ -2158,13 +2160,14 @@ ZlibStreamCmd(
 		}
 		break;
 	    case ao_buffer:
-		Tcl_AppendResult(interp,
-			"\"-buffer\" option not supported here", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"\"-buffer\" option not supported here", -1));
 		return TCL_ERROR;
 	    }
 	    if (flush == -2) {
-		Tcl_AppendResult(interp, "\"-flush\", \"-fullflush\" and "
-			"\"-finalize\" options are mutually exclusive", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"\"-flush\", \"-fullflush\" and \"-finalize\" options"
+			" are mutually exclusive", -1));
 		Tcl_SetErrorCode(interp, "TCL", "ZIP", "EXCLUSIVE", NULL);
 		return TCL_ERROR;
 	    }
@@ -2314,9 +2317,9 @@ ZlibTransformClose(
 		     * then interp may be NULL */
 		    if (!TclInThreadExit()) {
 			if (interp) {
-			    Tcl_AppendResult(interp,
-				    "error while finalizing file: ",
-				    Tcl_PosixError(interp), NULL);
+			    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+				    "error while finalizing file: %s",
+				    Tcl_PosixError(interp)));
 			}
 		    }
 		    result = TCL_ERROR;
@@ -2611,8 +2614,9 @@ ZlibTransformSetOption(			/* not used */
 
 	    if (Tcl_WriteRaw(cd->parent, cd->outBuffer,
 		    cd->outStream.next_out - (Bytef *) cd->outBuffer) < 0) {
-		Tcl_AppendResult(interp, "problem flushing channel: ",
-			Tcl_PosixError(interp), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"problem flushing channel: %s",
+			Tcl_PosixError(interp)));
 		return TCL_ERROR;
 	    }
 	}