more result generation conversion

18 files changed, 294 insertions, 260 deletions

diff --git a/generic/tclBinary.c b/generic/tclBinary.c
index 444e7fa..a1e836e 100644
--- a/generic/tclBinary.c
+++ b/generic/tclBinary.c
@@ -873,9 +873,9 @@ BinaryFormatCmd(
 		if (count == BINARY_ALL) {
 		    count = listc;
 		} else if (count > listc) {
-		    Tcl_AppendResult(interp,
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 			    "number of elements in list does not match count",
-			    NULL);
+			    -1));
 		    return TCL_ERROR;
 		}
 	    }
@@ -884,9 +884,8 @@ BinaryFormatCmd(
 
 	case 'x':
 	    if (count == BINARY_ALL) {
-		Tcl_AppendResult(interp,
-			"cannot use \"*\" in format string with \"x\"",
-			NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"cannot use \"*\" in format string with \"x\"", -1));
 		return TCL_ERROR;
 	    } else if (count == BINARY_NOCOUNT) {
 		count = 1;
@@ -1198,8 +1197,9 @@ BinaryFormatCmd(
 
  badValue:
     Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp, "expected ", errorString,
-	" string but got \"", errorValue, "\" instead", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "expected %s string but got \"%s\" instead",
+	    errorString, errorValue));
     return TCL_ERROR;
 
  badCount:
@@ -1217,12 +1217,13 @@ BinaryFormatCmd(
 
 	Tcl_UtfToUniChar(errorString, &ch);
 	buf[Tcl_UniCharToUtf(ch, buf)] = '\0';
-	Tcl_AppendResult(interp, "bad field specifier \"", buf, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad field specifier \"%s\"", buf));
 	return TCL_ERROR;
     }
 
  error:
-    Tcl_AppendResult(interp, errorString, NULL);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(errorString, -1));
     return TCL_ERROR;
 }
 
@@ -1586,12 +1587,13 @@ BinaryScanCmd(
 
 	Tcl_UtfToUniChar(errorString, &ch);
 	buf[Tcl_UniCharToUtf(ch, buf)] = '\0';
-	Tcl_AppendResult(interp, "bad field specifier \"", buf, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad field specifier \"%s\"", buf));
 	return TCL_ERROR;
     }
 
  error:
-    Tcl_AppendResult(interp, errorString, NULL);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(errorString, -1));
     return TCL_ERROR;
 }
 
diff --git a/generic/tclCkalloc.c b/generic/tclCkalloc.c
index 5b5a0d6..6443975 100644
--- a/generic/tclCkalloc.c
+++ b/generic/tclCkalloc.c
@@ -815,15 +815,16 @@ MemoryCmd(
     size_t len;
 
     if (argc < 2) {
-	Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
-		" option [args..]\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                "wrong # args: should be \"%s option [args..]\"", argv[0]));
 	return TCL_ERROR;
     }
 
-    if ((strcmp(argv[1],"active") == 0) || (strcmp(argv[1],"display") == 0)) {
+    if (strcmp(argv[1], "active") == 0 || strcmp(argv[1], "display") == 0) {
 	if (argc != 3) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
-		    " ", argv[1], " file\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "wrong # args: should be \"%s %s file\"",
+                    argv[0], argv[1]));
 	    return TCL_ERROR;
 	}
 	fileName = Tcl_TranslateFileName(interp, argv[2], &buffer);
@@ -833,7 +834,8 @@ MemoryCmd(
 	result = Tcl_DumpActiveMemory(fileName);
 	Tcl_DStringFree(&buffer);
 	if (result != TCL_OK) {
-	    Tcl_AppendResult(interp, "error accessing ", argv[2], NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf("error accessing %s: %s",
+                    argv[2], Tcl_PosixError(interp)));
 	    return TCL_ERROR;
 	}
 	return TCL_OK;
@@ -857,17 +859,17 @@ MemoryCmd(
 		"maximum bytes allocated", (unsigned long)maximum_bytes_malloced));
 	return TCL_OK;
     }
-    if (strcmp(argv[1],"init") == 0) {
+    if (strcmp(argv[1], "init") == 0) {
 	if (argc != 3) {
 	    goto bad_suboption;
 	}
 	init_malloced_bodies = (strcmp(argv[2],"on") == 0);
 	return TCL_OK;
     }
-    if (strcmp(argv[1],"objs") == 0) {
+    if (strcmp(argv[1], "objs") == 0) {
 	if (argc != 3) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
-		    " objs file\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "wrong # args: should be \"%s objs file\"", argv[0]));
 	    return TCL_ERROR;
 	}
 	fileName = Tcl_TranslateFileName(interp, argv[2], &buffer);
@@ -876,7 +878,9 @@ MemoryCmd(
 	}
 	fileP = fopen(fileName, "w");
 	if (fileP == NULL) {
-	    Tcl_AppendResult(interp, "cannot open output file", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "cannot open output file: %s",
+                    Tcl_PosixError(interp)));
 	    return TCL_ERROR;
 	}
 	TclDbDumpActiveObjects(fileP);
@@ -886,8 +890,8 @@ MemoryCmd(
     }
     if (strcmp(argv[1],"onexit") == 0) {
 	if (argc != 3) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
-		    " onexit file\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "wrong # args: should be \"%s onexit file\"", argv[0]));
 	    return TCL_ERROR;
 	}
 	fileName = Tcl_TranslateFileName(interp, argv[2], &buffer);
@@ -901,8 +905,8 @@ MemoryCmd(
     }
     if (strcmp(argv[1],"tag") == 0) {
 	if (argc != 3) {
-	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
-		    " tag string\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "wrong # args: should be \"%s tag string\"", argv[0]));
 	    return TCL_ERROR;
 	}
 	if ((curTagPtr != NULL) && (curTagPtr->refCount == 0)) {
@@ -939,19 +943,20 @@ MemoryCmd(
 	return TCL_OK;
     }
 
-    Tcl_AppendResult(interp, "bad option \"", argv[1],
-	    "\": should be active, break_on_malloc, info, init, objs, onexit, "
-	    "tag, trace, trace_on_at_malloc, or validate", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+            "bad option \"%s\": should be active, break_on_malloc, info, "
+            "init, objs, onexit, tag, trace, trace_on_at_malloc, or validate",
+            argv[1]));
     return TCL_ERROR;
 
   argError:
-    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
-	    " ", argv[1], " count\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+            "wrong # args: should be \"%s %s count\"", argv[0], argv[1]));
     return TCL_ERROR;
 
   bad_suboption:
-    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
-	    " ", argv[1], " on|off\"", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+            "wrong # args: should be \"%s %s on|off\"", argv[0], argv[1]));
     return TCL_ERROR;
 }
 
@@ -981,8 +986,8 @@ CheckmemCmd(
     const char *argv[])		/* String values of arguments. */
 {
     if (argc != 2) {
-	Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
-		" fileName\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                "wrong # args: should be \"%s fileName\"", argv[0]));
 	return TCL_ERROR;
     }
     tclMemDumpFileName = dumpFile;
diff --git a/generic/tclClock.c b/generic/tclClock.c
index e46ac69..6d2976d 100644
--- a/generic/tclClock.c
+++ b/generic/tclClock.c
@@ -1018,17 +1018,17 @@ ConvertUTCToLocalUsingC(
 
     tock = (time_t) fields->seconds;
     if ((Tcl_WideInt) tock != fields->seconds) {
-	Tcl_AppendResult(interp,
-		"number too large to represent as a Posix time", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"number too large to represent as a Posix time", -1));
 	Tcl_SetErrorCode(interp, "CLOCK", "argTooLarge", NULL);
 	return TCL_ERROR;
     }
     TzsetIfNecessary();
     timeVal = ThreadSafeLocalTime(&tock);
     if (timeVal == NULL) {
-	Tcl_AppendResult(interp,
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		"localtime failed (clock value may be too "
-		"large/small to represent)", NULL);
+		"large/small to represent)", -1));
 	Tcl_SetErrorCode(interp, "CLOCK", "localtimeFailed", NULL);
 	return TCL_ERROR;
     }
diff --git a/generic/tclCmdAH.c b/generic/tclCmdAH.c
index 4bb993e..5ca5cf8 100644
--- a/generic/tclCmdAH.c
+++ b/generic/tclCmdAH.c
@@ -194,7 +194,8 @@ Tcl_CaseObjCmd(
 
 	if (i == caseObjc-1) {
 	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "extra case pattern with no body", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "extra case pattern with no body", -1));
 	    return TCL_ERROR;
 	}
 
@@ -409,8 +410,9 @@ Tcl_CdObjCmd(
     } else {
 	result = Tcl_FSChdir(dir);
 	if (result != TCL_OK) {
-	    Tcl_AppendResult(interp, "couldn't change working directory to \"",
-		    TclGetString(dir), "\": ", Tcl_PosixError(interp), NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "couldn't change working directory to \"%s\": %s",
+		    TclGetString(dir), Tcl_PosixError(interp)));
 	    result = TCL_ERROR;
 	}
     }
@@ -642,8 +644,9 @@ EncodingDirsObjCmd(
 
     dirListObj = objv[2];
     if (Tcl_SetEncodingSearchPath(dirListObj) == TCL_ERROR) {
-	Tcl_AppendResult(interp, "expected directory list but got \"",
-		TclGetString(dirListObj), "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"expected directory list but got \"%s\"",
+		TclGetString(dirListObj)));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "ENCODING", "BADPATH",
 		NULL);
 	return TCL_ERROR;
@@ -1165,9 +1168,9 @@ FileAttrAccessTimeCmd(
 	tval.modtime = buf.st_mtime;
 
 	if (Tcl_FSUtime(objv[1], &tval) != 0) {
-	    Tcl_AppendResult(interp, "could not set access time for file \"",
-		    TclGetString(objv[1]), "\": ", Tcl_PosixError(interp),
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "could not set access time for file \"%s\": %s",
+		    TclGetString(objv[1]), Tcl_PosixError(interp)));
 	    return TCL_ERROR;
 	}
 
@@ -1237,9 +1240,9 @@ FileAttrModifyTimeCmd(
 	tval.modtime = newTime;
 
 	if (Tcl_FSUtime(objv[1], &tval) != 0) {
-	    Tcl_AppendResult(interp, "could not set modification time for "
-		    "file \"", TclGetString(objv[1]), "\": ",
-		    Tcl_PosixError(interp), NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "could not set modification time for file \"%s\": %s",
+		    TclGetString(objv[1]), Tcl_PosixError(interp)));
 	    return TCL_ERROR;
 	}
 
@@ -1990,8 +1993,9 @@ PathSplitCmd(
     }
     res = Tcl_FSSplitPath(objv[1], NULL);
     if (res == NULL) {
-	Tcl_AppendResult(interp, "could not read \"", TclGetString(objv[1]),
-		"\": no such file or directory", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"could not read \"%s\": no such file or directory",
+		TclGetString(objv[1])));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "PATHSPLIT", "NONESUCH",
 		NULL);
 	return TCL_ERROR;
@@ -2212,9 +2216,9 @@ GetStatBuf(
 
     if (status < 0) {
 	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "could not read \"",
-		    TclGetString(pathPtr), "\": ",
-		    Tcl_PosixError(interp), NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "could not read \"%s\": %s",
+		    TclGetString(pathPtr), Tcl_PosixError(interp)));
 	}
 	return TCL_ERROR;
     }
@@ -2649,7 +2653,8 @@ TclNRForeachCmd(
 	TclListObjGetElements(NULL, statePtr->vCopyList[i],
 		&statePtr->varcList[i], &statePtr->varvList[i]);
 	if (statePtr->varcList[i] < 1) {
-	    Tcl_AppendResult(interp, "foreach varlist is empty", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "foreach varlist is empty", -1));
 	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "FOREACH",
 		    "NEEDVARS", NULL);
 	    result = TCL_ERROR;
diff --git a/generic/tclCmdMZ.c b/generic/tclCmdMZ.c
index 7e94d9f..9e720ea 100644
--- a/generic/tclCmdMZ.c
+++ b/generic/tclCmdMZ.c
@@ -204,8 +204,8 @@ Tcl_RegexpObjCmd(
      */
 
     if (doinline && ((objc - 2) != 0)) {
-	Tcl_AppendResult(interp, "regexp match variables not allowed"
-		" when using -inline", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"regexp match variables not allowed when using -inline", -1));
 	goto optionError;
     }
 
@@ -1839,8 +1839,8 @@ StringMapCmd(
 		strncmp(string, "-nocase", (size_t) length2) == 0) {
 	    nocase = 1;
 	} else {
-	    Tcl_AppendResult(interp, "bad option \"", string,
-		    "\": must be -nocase", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad option \"%s\": must be -nocase", string));
 	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "option",
 		    string, NULL);
 	    return TCL_ERROR;
@@ -2106,8 +2106,8 @@ StringMatchCmd(
 	    strncmp(string, "-nocase", (size_t) length) == 0) {
 	    nocase = TCL_MATCH_NOCASE;
 	} else {
-	    Tcl_AppendResult(interp, "bad option \"", string,
-		    "\": must be -nocase", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad option \"%s\": must be -nocase", string));
 	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "option",
 		    string, NULL);
 	    return TCL_ERROR;
@@ -2567,8 +2567,9 @@ StringEqualCmd(
 		return TCL_ERROR;
 	    }
 	} else {
-	    Tcl_AppendResult(interp, "bad option \"", string2,
-		    "\": must be -nocase or -length", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad option \"%s\": must be -nocase or -length",
+		    string2));
 	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "option",
 		    string2, NULL);
 	    return TCL_ERROR;
@@ -2716,8 +2717,9 @@ StringCmpCmd(
 		return TCL_ERROR;
 	    }
 	} else {
-	    Tcl_AppendResult(interp, "bad option \"", string2,
-		    "\": must be -nocase or -length", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad option \"%s\": must be -nocase or -length",
+		    string2));
 	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "option",
 		    string2, NULL);
 	    return TCL_ERROR;
@@ -3515,9 +3517,9 @@ TclNRSwitchObjCmd(
 		 * Mode already set via -exact, -glob, or -regexp.
 		 */
 
-		Tcl_AppendResult(interp, "bad option \"",
-			TclGetString(objv[i]), "\": ", options[mode],
-			" option already found", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"bad option \"%s\": %s option already found",
+			TclGetString(objv[i]), options[mode]));
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "SWITCH",
 			"DOUBLEOPT", NULL);
 		return TCL_ERROR;
@@ -3534,8 +3536,9 @@ TclNRSwitchObjCmd(
 	case OPT_INDEXV:
 	    i++;
 	    if (i >= objc-2) {
-		Tcl_AppendResult(interp, "missing variable name argument to ",
-			"-indexvar", " option", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"missing variable name argument to %s option",
+			"-indexvar"));
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "SWITCH",
 			"NOVAR", NULL);
 		return TCL_ERROR;
@@ -3546,8 +3549,9 @@ TclNRSwitchObjCmd(
 	case OPT_MATCHV:
 	    i++;
 	    if (i >= objc-2) {
-		Tcl_AppendResult(interp, "missing variable name argument to ",
-			"-matchvar", " option", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"missing variable name argument to %s option",
+			"-matchvar"));
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "SWITCH",
 			"NOVAR", NULL);
 		return TCL_ERROR;
@@ -3565,15 +3569,15 @@ TclNRSwitchObjCmd(
 	return TCL_ERROR;
     }
     if (indexVarObj != NULL && mode != OPT_REGEXP) {
-	Tcl_AppendResult(interp,
-		"-indexvar option requires -regexp option", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"%s option requires -regexp option", "-indexvar"));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "SWITCH",
 		"MODERESTRICTION", NULL);
 	return TCL_ERROR;
     }
     if (matchVarObj != NULL && mode != OPT_REGEXP) {
-	Tcl_AppendResult(interp,
-		"-matchvar option requires -regexp option", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"%s option requires -regexp option", "-matchvar"));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "SWITCH",
 		"MODERESTRICTION", NULL);
 	return TCL_ERROR;
@@ -3622,7 +3626,8 @@ TclNRSwitchObjCmd(
 
     if (objc % 2) {
 	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "extra switch pattern with no body", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"extra switch pattern with no body", -1));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "SWITCH", "BADARM",
 		NULL);
 
@@ -3637,10 +3642,10 @@ TclNRSwitchObjCmd(
 	if (splitObjs) {
 	    for (i=0 ; i<objc ; i+=2) {
 		if (TclGetString(objv[i])[0] == '#') {
-		    Tcl_AppendResult(interp, ", this may be due to a "
-			    "comment incorrectly placed outside of a "
-			    "switch body - see the \"switch\" "
-			    "documentation", NULL);
+		    Tcl_AppendToObj(Tcl_GetObjResult(interp),
+			    ", this may be due to a comment incorrectly"
+			    " placed outside of a switch body - see the"
+			    " \"switch\" documentation", -1);
 		    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "SWITCH",
 			    "BADARM", "COMMENT?", NULL);
 		    break;
@@ -3657,9 +3662,9 @@ TclNRSwitchObjCmd(
      */
 
     if (strcmp(TclGetString(objv[objc-1]), "-") == 0) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "no body specified for pattern \"",
-		TclGetString(objv[objc-2]), "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"no body specified for pattern \"%s\"",
+		TclGetString(objv[objc-2])));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "SWITCH", "BADARM",
 		"FALLTHROUGH", NULL);
 	return TCL_ERROR;
@@ -3985,7 +3990,8 @@ Tcl_ThrowObjCmd(
     if (Tcl_ListObjLength(interp, objv[1], &len) != TCL_OK) {
 	return TCL_ERROR;
     } else if (len < 1) {
-	Tcl_AppendResult(interp, "type must be non-empty list", NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"type must be non-empty list", -1));
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "THROW", "BADEXCEPTION",
 		NULL);
 	return TCL_ERROR;
@@ -4169,15 +4175,16 @@ TclNRTryObjCmd(
 	switch ((enum Handlers) type) {
 	case TryFinally:	/* finally script */
 	    if (i < objc-2) {
-		Tcl_AppendResult(interp, "finally clause must be last", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"finally clause must be last", -1));
 		Tcl_DecrRefCount(handlersObj);
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "TRY", "FINALLY",
 			"NONTERMINAL", NULL);
 		return TCL_ERROR;
 	    } else if (i == objc-1) {
-		Tcl_AppendResult(interp, "wrong # args to finally clause: ",
-			"must be \"", TclGetString(objv[0]),
-			" ... finally script\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"wrong # args to finally clause: must be"
+			" \"... finally script\"", -1));
 		Tcl_DecrRefCount(handlersObj);
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "TRY", "FINALLY",
 			"ARGUMENT", NULL);
@@ -4188,15 +4195,16 @@ TclNRTryObjCmd(
 
 	case TryOn:		/* on code variableList script */
 	    if (i > objc-4) {
-		Tcl_AppendResult(interp, "wrong # args to on clause: ",
-			"must be \"", TclGetString(objv[0]),
-			" ... on code variableList script\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"wrong # args to on clause: must be \"... on code"
+			" variableList script\"", -1));
 		Tcl_DecrRefCount(handlersObj);
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "TRY", "ON",
 			"ARGUMENT", NULL);
 		return TCL_ERROR;
 	    }
-	    if (TCL_ERROR == TclGetCompletionCodeFromObj(interp, objv[i+1], &code)) {
+	    if (TclGetCompletionCodeFromObj(interp, objv[i+1],
+		    &code) != TCL_OK) {
 		Tcl_DecrRefCount(handlersObj);
 		return TCL_ERROR;
 	    }
@@ -4205,9 +4213,10 @@ TclNRTryObjCmd(
 
 	case TryTrap:		/* trap pattern variableList script */
 	    if (i > objc-4) {
-		Tcl_AppendResult(interp, "wrong # args to trap clause: ",
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"wrong # args to trap clause: "
 			"must be \"... trap pattern variableList script\"",
-			NULL);
+			-1));
 		Tcl_DecrRefCount(handlersObj);
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "TRY", "TRAP",
 			"ARGUMENT", NULL);
@@ -4248,9 +4257,8 @@ TclNRTryObjCmd(
 	}
     }
     if (bodyShared) {
-	Tcl_AppendResult(interp,
-		"last non-finally clause must not have a body of \"-\"",
-		NULL);
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"last non-finally clause must not have a body of \"-\"", -1));
 	Tcl_DecrRefCount(handlersObj);
 	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "TRY", "BADFALLTHROUGH",
 		NULL);
diff --git a/generic/tclEncoding.c b/generic/tclEncoding.c
index 0fa6661..7a55724 100644
--- a/generic/tclEncoding.c
+++ b/generic/tclEncoding.c
@@ -1542,7 +1542,8 @@ OpenEncodingFileChannel(
     }
 
     if ((NULL == chan) && (interp != NULL)) {
-	Tcl_AppendResult(interp, "unknown encoding \"", name, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"unknown encoding \"%s\"", name));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "ENCODING", name, NULL);
     }
     Tcl_DecrRefCount(fileNameObj);
@@ -1616,7 +1617,8 @@ LoadEncodingFile(
 	break;
     }
     if ((encoding == NULL) && (interp != NULL)) {
-	Tcl_AppendResult(interp, "invalid encoding file \"", name, "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"invalid encoding file \"%s\"", name));
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "ENCODING", name, NULL);
     }
     Tcl_Close(NULL, chan);
diff --git a/generic/tclEvent.c b/generic/tclEvent.c
index e65862c..0b585b6 100644
--- a/generic/tclEvent.c
+++ b/generic/tclEvent.c
@@ -1416,7 +1416,7 @@ Tcl_VwaitObjCmd(
 	}
 	if (Tcl_LimitExceeded(interp)) {
 	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "limit exceeded", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj("limit exceeded", -1));
 	    break;
 	}
     }
@@ -1426,8 +1426,9 @@ Tcl_VwaitObjCmd(
 
     if (!foundEvent) {
 	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "can't wait for variable \"", nameString,
-		"\": would wait forever", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't wait for variable \"%s\": would wait forever",
+		nameString));
 	Tcl_SetErrorCode(interp, "TCL", "EVENT", "NO_SOURCES", NULL);
 	return TCL_ERROR;
     }
@@ -1519,7 +1520,7 @@ Tcl_UpdateObjCmd(
 	}
 	if (Tcl_LimitExceeded(interp)) {
 	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "limit exceeded", NULL);
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj("limit exceeded", -1));
 	    return TCL_ERROR;
 	}
     }
diff --git a/generic/tclFCmd.c b/generic/tclFCmd.c
index a868fe3..032dda7 100644
--- a/generic/tclFCmd.c
+++ b/generic/tclFCmd.c
@@ -152,9 +152,9 @@ FileCopyRename(
 	if ((objc - i) > 2) {
 	    errno = ENOTDIR;
 	    Tcl_PosixError(interp);
-	    Tcl_AppendResult(interp, "error ",
-		    (copyFlag ? "copying" : "renaming"), ": target \"",
-		    TclGetString(target), "\" is not a directory", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "error %s: target \"%s\" is not a directory",
+		    (copyFlag?"copying":"renaming"), TclGetString(target)));
 	    result = TCL_ERROR;
 	} else {
 	    /*
@@ -304,8 +304,9 @@ TclFileMakeDirsCmd(
 
   done:
     if (errfile != NULL) {
-	Tcl_AppendResult(interp, "can't create directory \"",
-		TclGetString(errfile), "\": ", Tcl_PosixError(interp), NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't create directory \"%s\": %s",
+		TclGetString(errfile), Tcl_PosixError(interp)));
 	result = TCL_ERROR;
     }
     if (split != NULL) {
@@ -384,9 +385,9 @@ TclFileDeleteCmd(
 	    result = Tcl_FSRemoveDirectory(objv[i], force, &errorBuffer);
 	    if (result != TCL_OK) {
 		if ((force == 0) && (errno == EEXIST)) {
-		    Tcl_AppendResult(interp, "error deleting \"",
-			    TclGetString(objv[i]), "\": directory not empty",
-			    NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "error deleting \"%s\": directory not empty",
+			    TclGetString(objv[i])));
 		    Tcl_PosixError(interp);
 		    goto done;
 		}
@@ -426,12 +427,13 @@ TclFileDeleteCmd(
 	     * We try to accomodate poor error results from our Tcl_FS calls.
 	     */
 
-	    Tcl_AppendResult(interp, "error deleting unknown file: ",
-		    Tcl_PosixError(interp), NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "error deleting unknown file: %s",
+		    Tcl_PosixError(interp)));
 	} else {
-	    Tcl_AppendResult(interp, "error deleting \"",
-		    TclGetString(errfile), "\": ", Tcl_PosixError(interp),
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "error deleting \"%s\": %s",
+		    TclGetString(errfile), Tcl_PosixError(interp)));
 	}
     }
 
@@ -540,17 +542,17 @@ CopyRenameOneFile(
 	if (S_ISDIR(sourceStatBuf.st_mode)
 		&& !S_ISDIR(targetStatBuf.st_mode)) {
 	    errno = EISDIR;
-	    Tcl_AppendResult(interp, "can't overwrite file \"",
-		    TclGetString(target), "\" with directory \"",
-		    TclGetString(source), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't overwrite file \"%s\" with directory \"%s\"",
+		    TclGetString(target), TclGetString(source)));
 	    goto done;
 	}
 	if (!S_ISDIR(sourceStatBuf.st_mode)
 		&& S_ISDIR(targetStatBuf.st_mode)) {
 	    errno = EISDIR;
-	    Tcl_AppendResult(interp, "can't overwrite directory \"",
-		    TclGetString(target), "\" with file \"",
-		    TclGetString(source), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "can't overwrite directory \"%s\" with file \"%s\"",
+		    TclGetString(target), TclGetString(source)));
 	    goto done;
 	}
 
@@ -581,10 +583,10 @@ CopyRenameOneFile(
 	}
 
 	if (errno == EINVAL) {
-	    Tcl_AppendResult(interp, "error renaming \"",
-		    TclGetString(source), "\" to \"", TclGetString(target),
-		    "\": trying to rename a volume or "
-		    "move a directory into itself", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "error renaming \"%s\" to \"%s\": trying to rename a"
+		    " volume or move a directory into itself",
+		    TclGetString(source), TclGetString(target)));
 	    goto done;
 	} else if (errno != EXDEV) {
 	    errfile = target;
@@ -628,8 +630,9 @@ CopyRenameOneFile(
 	     * Actual file doesn't exist.
 	     */
 
-	    Tcl_AppendResult(interp, "error copying \"", TclGetString(source),
-		    "\": the target of this link doesn't exist", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "error copying \"%s\": the target of this link doesn't"
+		    " exist", TclGetString(source)));
 	    goto done;
 	} else {
 	    int counter = 0;
@@ -764,23 +767,27 @@ CopyRenameOneFile(
 	    }
 	}
 	if (result != TCL_OK) {
-	    Tcl_AppendResult(interp, "can't unlink \"", TclGetString(errfile),
-		    "\": ", Tcl_PosixError(interp), NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf("can't unlink \"%s\": %s",
+		    TclGetString(errfile), Tcl_PosixError(interp)));
 	    errfile = NULL;
 	}
     }
 
   done:
     if (errfile != NULL) {
-	Tcl_AppendResult(interp, "error ", (copyFlag ? "copying" : "renaming"),
-		 " \"", TclGetString(source), NULL);
+	Tcl_Obj *errorMsg = Tcl_ObjPrintf("error %s \"%s\"",
+		(copyFlag ? "copying" : "renaming"), TclGetString(source));
+
 	if (errfile != source) {
-	    Tcl_AppendResult(interp, "\" to \"", TclGetString(target), NULL);
+	    Tcl_AppendPrintfToObj(errorMsg, " to \"%s\"",
+		    TclGetString(target));
 	    if (errfile != target) {
-		Tcl_AppendResult(interp, "\": \"", TclGetString(errfile),NULL);
+		Tcl_AppendPrintfToObj(errorMsg, ": \"%s\"",
+			TclGetString(errfile));
 	    }
 	}
-	Tcl_AppendResult(interp, "\": ", Tcl_PosixError(interp), NULL);
+	Tcl_AppendPrintfToObj(errorMsg, ": %s", Tcl_PosixError(interp));
+	Tcl_SetObjResult(interp, errorMsg);
     }
     if (errorBuffer != NULL) {
 	Tcl_DecrRefCount(errorBuffer);
@@ -983,9 +990,10 @@ TclFileAttrsCmd(
 		 * There was an error, probably that the filePtr is not
 		 * accepted by any filesystem
 		 */
-		Tcl_AppendResult(interp, "could not read \"",
-			TclGetString(filePtr), "\": ", Tcl_PosixError(interp),
-			NULL);
+
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"could not read \"%s\": %s",
+			TclGetString(filePtr), Tcl_PosixError(interp)));
 	    }
 	    return TCL_ERROR;
 	}
@@ -1071,9 +1079,9 @@ TclFileAttrsCmd(
 	Tcl_Obj *objPtr = NULL;
 
 	if (numObjStrings == 0) {
-	    Tcl_AppendResult(interp, "bad option \"", TclGetString(objv[0]),
-		    "\", there are no file attributes in this filesystem.",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad option \"%s\", there are no file attributes in this"
+		    " filesystem", TclGetString(objv[0])));
 	    Tcl_SetErrorCode(interp, "TCL","OPERATION","FATTR","NONE", NULL);
 	    goto end;
 	}
@@ -1098,9 +1106,9 @@ TclFileAttrsCmd(
 	int i, index;
 
 	if (numObjStrings == 0) {
-	    Tcl_AppendResult(interp, "bad option \"", TclGetString(objv[0]),
-		    "\", there are no file attributes in this filesystem.",
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad option \"%s\", there are no file attributes in this"
+		    " filesystem", TclGetString(objv[0])));
 	    Tcl_SetErrorCode(interp, "TCL","OPERATION","FATTR","NONE", NULL);
 	    goto end;
 	}
@@ -1114,8 +1122,8 @@ TclFileAttrsCmd(
 		TclFreeIntRep(objv[i]);
 	    }
 	    if (i + 1 == objc) {
-		Tcl_AppendResult(interp, "value for \"",
-			TclGetString(objv[i]), "\" missing", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"value for \"%s\" missing", TclGetString(objv[i])));
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "FATTR",
 			"NOVALUE", NULL);
 		goto end;
@@ -1224,9 +1232,9 @@ TclFileLinkCmd(
 	     */
 
 	    if (errno == EEXIST) {
-		Tcl_AppendResult(interp, "could not create new link \"",
-			TclGetString(objv[index]),
-			"\": that path already exists", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"could not create new link \"%s\": that path already"
+			" exists", TclGetString(objv[index])));
 		Tcl_PosixError(interp);
 	    } else if (errno == ENOENT) {
 		/*
@@ -1244,23 +1252,23 @@ TclFileLinkCmd(
 		access = Tcl_FSAccess(dirPtr, F_OK);
 		Tcl_DecrRefCount(dirPtr);
 		if (access != 0) {
-		    Tcl_AppendResult(interp, "could not create new link \"",
-			    TclGetString(objv[index]),
-			    "\": no such file or directory", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "could not create new link \"%s\": no such file"
+			    " or directory", TclGetString(objv[index])));
 		    Tcl_PosixError(interp);
 		} else {
-		    Tcl_AppendResult(interp, "could not create new link \"",
-			    TclGetString(objv[index]), "\": target \"",
-			    TclGetString(objv[index+1]), "\" doesn't exist",
-			    NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "could not create new link \"%s\": target \"%s\" "
+			    "doesn't exist", TclGetString(objv[index]),
+			    TclGetString(objv[index+1])));
 		    errno = ENOENT;
 		    Tcl_PosixError(interp);
 		}
 	    } else {
-		Tcl_AppendResult(interp, "could not create new link \"",
-			TclGetString(objv[index]), "\" pointing to \"",
-			TclGetString(objv[index+1]), "\": ",
-			Tcl_PosixError(interp), NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"could not create new link \"%s\" pointing to \"%s\": %s",
+			TclGetString(objv[index]),
+			TclGetString(objv[index+1]), Tcl_PosixError(interp)));
 	    }
 	    return TCL_ERROR;
 	}
@@ -1275,9 +1283,9 @@ TclFileLinkCmd(
 
 	contents = Tcl_FSLink(objv[index], NULL, 0);
 	if (contents == NULL) {
-	    Tcl_AppendResult(interp, "could not read link \"",
-		    TclGetString(objv[index]), "\": ", Tcl_PosixError(interp),
-		    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "could not read link \"%s\": %s",
+		    TclGetString(objv[index]), Tcl_PosixError(interp)));
 	    return TCL_ERROR;
 	}
     }
@@ -1332,8 +1340,9 @@ TclFileReadLinkCmd(
     contents = Tcl_FSLink(objv[1], NULL, 0);
 
     if (contents == NULL) {
-	Tcl_AppendResult(interp, "could not readlink \"",
-		TclGetString(objv[1]), "\": ", Tcl_PosixError(interp), NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"could not read link \"%s\": %s",
+		TclGetString(objv[1]), Tcl_PosixError(interp)));
 	return TCL_ERROR;
     }
     Tcl_SetObjResult(interp, contents);
@@ -1487,8 +1496,8 @@ TclFileTemporaryCmd(
 	if (nameVarObj) {
 	    TclDecrRefCount(nameObj);
 	}
-	Tcl_AppendResult(interp, "can't create temporary file: ",
-		Tcl_PosixError(interp), NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't create temporary file: %s", Tcl_PosixError(interp)));
 	return TCL_ERROR;
     }
     Tcl_RegisterChannel(interp, chan);
@@ -1499,7 +1508,7 @@ TclFileTemporaryCmd(
 	    return TCL_ERROR;
 	}
     }
-    Tcl_AppendResult(interp, Tcl_GetChannelName(chan), NULL);
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(Tcl_GetChannelName(chan), -1));
     return TCL_OK;
 }
 
diff --git a/generic/tclIndexObj.c b/generic/tclIndexObj.c
index 85e0730..731d759 100644
--- a/generic/tclIndexObj.c
+++ b/generic/tclIndexObj.c
@@ -600,8 +600,9 @@ PrefixMatchObjCmd(
 	    flags |= TCL_EXACT;
 	    break;
 	case PRFMATCH_MESSAGE:
-	    if (i > (objc - 4)) {
-		Tcl_AppendResult(interp, "missing message", NULL);
+	    if (i > objc-4) {
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"missing value for -message", -1));
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "NOARG", NULL);
 		return TCL_ERROR;
 	    }
@@ -610,7 +611,8 @@ PrefixMatchObjCmd(
 	    break;
 	case PRFMATCH_ERROR:
 	    if (i > objc-4) {
-		Tcl_AppendResult(interp, "missing error options", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"missing value for -error", -1));
 		Tcl_SetErrorCode(interp, "TCL", "OPERATION", "NOARG", NULL);
 		return TCL_ERROR;
 	    }
@@ -620,8 +622,9 @@ PrefixMatchObjCmd(
 		return TCL_ERROR;
 	    }
 	    if ((errorLength % 2) != 0) {
-		Tcl_AppendResult(interp, "error options must have an even"
-			" number of elements", NULL);
+		Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			"error options must have an even number of elements",
+			-1));
 		Tcl_SetErrorCode(interp, "TCL", "VALUE", "DICTIONARY", NULL);
 		return TCL_ERROR;
 	    }
@@ -1174,8 +1177,8 @@ Tcl_ParseArgsObjv(
 		goto gotMatch;
 	    }
 	    if (matchPtr != NULL) {
-		Tcl_AppendResult(interp, "ambiguous option \"", str, "\"",
-			NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"ambiguous option \"%s\"", str));
 		goto error;
 	    }
 	    matchPtr = infoPtr;
@@ -1187,8 +1190,8 @@ Tcl_ParseArgsObjv(
 	     */
 
 	    if (remObjv == NULL) {
-		Tcl_AppendResult(interp, "unrecognized argument \"", str,
-			"\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"unrecognized argument \"%s\"", str));
 		goto error;
 	    }
 
@@ -1213,9 +1216,9 @@ Tcl_ParseArgsObjv(
 	    }
 	    if (Tcl_GetIntFromObj(interp, objv[srcIndex],
 		    (int *) infoPtr->dstPtr) == TCL_ERROR) {
-		Tcl_AppendResult(interp, "expected integer argument for \"",
-			infoPtr->keyStr, "\" but got \"",
-			Tcl_GetString(objv[srcIndex]), "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"expected integer argument for \"%s\" but got \"%s\"",
+			infoPtr->keyStr, Tcl_GetString(objv[srcIndex])));
 		goto error;
 	    }
 	    srcIndex++;
@@ -1246,9 +1249,9 @@ Tcl_ParseArgsObjv(
 	    }
 	    if (Tcl_GetDoubleFromObj(interp, objv[srcIndex],
 		    (double *) infoPtr->dstPtr) == TCL_ERROR) {
-		Tcl_AppendResult(interp, "expected floating-point argument ",
-			"for \"", infoPtr->keyStr, "\" but got \"",
-			Tcl_GetString(objv[srcIndex]), "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"expected floating-point argument for \"%s\" but got \"%s\"",
+			infoPtr->keyStr, Tcl_GetString(objv[srcIndex])));
 		goto error;
 	    }
 	    srcIndex++;
@@ -1322,8 +1325,8 @@ Tcl_ParseArgsObjv(
      */
 
   missingArg:
-    Tcl_AppendResult(interp, "\"", str,
-	    "\" option requires an additional argument", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "\"%s\" option requires an additional argument", str));
   error:
     if (leftovers != NULL) {
 	ckfree(leftovers);
@@ -1361,6 +1364,7 @@ PrintUsage(
 #define NUM_SPACES 20
     static const char spaces[] = "                    ";
     char tmp[TCL_DOUBLE_SPACE];
+    Tcl_Obj *msg;
 
     /*
      * First, compute the width of the widest option key, so that we can make
@@ -1384,39 +1388,39 @@ PrintUsage(
      * Now add the option information, with pretty-printing.
      */
 
-    Tcl_AppendResult(interp, "Command-specific options:", NULL);
+    msg = Tcl_NewStringObj("Command-specific options:", -1);
     for (infoPtr = argTable; infoPtr->type != TCL_ARGV_END; infoPtr++) {
 	if ((infoPtr->type == TCL_ARGV_HELP) && (infoPtr->keyStr == NULL)) {
-	    Tcl_AppendResult(interp, "\n", infoPtr->helpStr, NULL);
+	    Tcl_AppendPrintfToObj(msg, "\n%s", infoPtr->helpStr);
 	    continue;
 	}
-	Tcl_AppendResult(interp, "\n ", infoPtr->keyStr, ":", NULL);
+	Tcl_AppendPrintfToObj(msg, "\n %s:", infoPtr->keyStr);
 	numSpaces = width + 1 - strlen(infoPtr->keyStr);
 	while (numSpaces > 0) {
 	    if (numSpaces >= NUM_SPACES) {
-		Tcl_AppendResult(interp, spaces, NULL);
+		Tcl_AppendToObj(msg, spaces, NUM_SPACES);
 	    } else {
-		Tcl_AppendResult(interp, spaces+NUM_SPACES-numSpaces, NULL);
+		Tcl_AppendToObj(msg, spaces, numSpaces);
 	    }
 	    numSpaces -= NUM_SPACES;
 	}
-	Tcl_AppendResult(interp, infoPtr->helpStr, NULL);
+	Tcl_AppendToObj(msg, infoPtr->helpStr, -1);
 	switch (infoPtr->type) {
 	case TCL_ARGV_INT:
-	    sprintf(tmp, "%d", *((int *) infoPtr->dstPtr));
-	    Tcl_AppendResult(interp, "\n\t\tDefault value: ", tmp, NULL);
+	    Tcl_AppendPrintfToObj(msg, "\n\t\tDefault value: %d",
+		    *((int *) infoPtr->dstPtr));
 	    break;
 	case TCL_ARGV_FLOAT:
+	    Tcl_AppendPrintfToObj(msg, "\n\t\tDefault value: %g",
+		    *((double *) infoPtr->dstPtr));
 	    sprintf(tmp, "%g", *((double *) infoPtr->dstPtr));
-	    Tcl_AppendResult(interp, "\n\t\tDefault value: ", tmp, NULL);
 	    break;
 	case TCL_ARGV_STRING: {
-	    char *string;
+	    char *string = *((char **) infoPtr->dstPtr);
 
-	    string = *((char **) infoPtr->dstPtr);
 	    if (string != NULL) {
-		Tcl_AppendResult(interp, "\n\t\tDefault value: \"", string,
-			"\"", NULL);
+		Tcl_AppendPrintfToObj(msg, "\n\t\tDefault value: \"%s\"",
+			string);
 	    }
 	    break;
 	}
@@ -1424,6 +1428,7 @@ PrintUsage(
 	    break;
 	}
     }
+    Tcl_SetObjResult(interp, msg);
 }
 
 /*
@@ -1435,8 +1440,8 @@ PrintUsage(
  *
  * Results:
  *	Returns TCL_ERROR if the value is an invalid completion code.
- *	Otherwise, returns TCL_OK, and writes the completion code to
- *  the pointer provided.
+ *	Otherwise, returns TCL_OK, and writes the completion code to the
+ *	pointer provided.
  *
  * Side effects:
  *	None.
@@ -1448,30 +1453,30 @@ int
 TclGetCompletionCodeFromObj(
     Tcl_Interp *interp,		/* Current interpreter. */
     Tcl_Obj *value,
-    int *code)			/* Argument objects. */
+    int *codePtr)		/* Argument objects. */
 {
     static const char *const returnCodes[] = {
 	"ok", "error", "return", "break", "continue", NULL
     };
 
     if ((value->typePtr != &indexType)
-	    && (TCL_OK == TclGetIntFromObj(NULL, value, code))) {
+	    && TclGetIntFromObj(NULL, value, codePtr) == TCL_OK) {
 	return TCL_OK;
     }
-    if (TCL_OK == Tcl_GetIndexFromObj(NULL, value, returnCodes, NULL,
-		TCL_EXACT, code)) {
+    if (Tcl_GetIndexFromObj(NULL, value, returnCodes, NULL, TCL_EXACT,
+	    codePtr) == TCL_OK) {
 	return TCL_OK;
     }
+
     /*
      * Value is not a legal completion code.
      */
 
     if (interp != NULL) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "bad completion code \"",
-		TclGetString(value),
-		"\": must be ok, error, return, break, "
-		"continue, or an integer", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad completion code \"%s\": must be"
+		" ok, error, return, break, continue, or an integer",
+		TclGetString(value)));
 	Tcl_SetErrorCode(interp, "TCL", "RESULT", "ILLEGAL_CODE", NULL);
     }
     return TCL_ERROR;
diff --git a/generic/tclParse.c b/generic/tclParse.c
index aab2fac..309e232 100644
--- a/generic/tclParse.c
+++ b/generic/tclParse.c
@@ -1779,8 +1779,8 @@ Tcl_ParseBraces(
 		break;
 	    case '#' :
 		if (openBrace && TclIsSpaceProc(src[-1])) {
-		    Tcl_AppendResult(parsePtr->interp,
-			    ": possible unbalanced brace in comment", NULL);
+		    Tcl_AppendToObj(Tcl_GetObjResult(parsePtr->interp),
+			    ": possible unbalanced brace in comment", -1);
 		    goto error;
 		}
 		break;
diff --git a/generic/tclPathObj.c b/generic/tclPathObj.c
index 8bae4fb..db07c0e 100644
--- a/generic/tclPathObj.c
+++ b/generic/tclPathObj.c
@@ -1492,9 +1492,8 @@ MakePathFromNormalized(
 	if (pathPtr->bytes == NULL) {
 	    if (pathPtr->typePtr->updateStringProc == NULL) {
 		if (interp != NULL) {
-		    Tcl_ResetResult(interp);
-		    Tcl_AppendResult(interp, "can't find object"
-			    "string representation", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "can't find object string representation", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "VALUE", "PATH", "WTF",
 			    NULL);
 		}
@@ -2368,9 +2367,9 @@ SetFsPathFromAny(
 	    dir = TclGetEnv("HOME", &dirString);
 	    if (dir == NULL) {
 		if (interp) {
-		    Tcl_ResetResult(interp);
-		    Tcl_AppendResult(interp, "couldn't find HOME environment "
-			    "variable to expand path", NULL);
+		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+			    "couldn't find HOME environment variable to"
+			    " expand path", -1));
 		    Tcl_SetErrorCode(interp, "TCL", "VALUE", "PATH",
 			    "HOMELESS", NULL);
 		}
@@ -2387,9 +2386,8 @@ SetFsPathFromAny(
 	    Tcl_DStringInit(&temp);
 	    if (TclpGetUserHome(name+1, &temp) == NULL) {
 		if (interp != NULL) {
-		    Tcl_ResetResult(interp);
-		    Tcl_AppendResult(interp, "user \"", name+1,
-			    "\" doesn't exist", NULL);
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "user \"%s\" doesn't exist", name+1));
 		    Tcl_SetErrorCode(interp, "TCL", "VALUE", "PATH", "NOUSER",
 			    NULL);
 		}
diff --git a/generic/tclRegexp.c b/generic/tclRegexp.c
index 53d7153..6c1dc08 100644
--- a/generic/tclRegexp.c
+++ b/generic/tclRegexp.c
@@ -714,14 +714,14 @@ TclRegError(
     int status)			/* Status code to report. */
 {
     char buf[100];		/* ample in practice */
-    char cbuf[100];		/* lots in practice */
+    char cbuf[TCL_INTEGER_SPACE];
     size_t n;
     const char *p;
 
     Tcl_ResetResult(interp);
     n = TclReError(status, NULL, buf, sizeof(buf));
     p = (n > sizeof(buf)) ? "..." : "";
-    Tcl_AppendResult(interp, msg, buf, p, NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf("%s%s%s", msg, buf, p));
 
     sprintf(cbuf, "%d", status);
     (void) TclReError(REG_ITOA, NULL, cbuf, sizeof(cbuf));
diff --git a/generic/tclResult.c b/generic/tclResult.c
index 4443cc1..17aac74 100644
--- a/generic/tclResult.c
+++ b/generic/tclResult.c
@@ -1390,10 +1390,9 @@ TclMergeReturnOptions(
 		 * Value is not a legal dictionary.
 		 */
 
-		Tcl_ResetResult(interp);
-		Tcl_AppendResult(interp, "bad ", compare,
-			" value: expected dictionary but got \"",
-			TclGetString(objv[1]), "\"", NULL);
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                        "bad %s value: expected dictionary but got \"%s\"",
+                        compare, TclGetString(objv[1])));
 		Tcl_SetErrorCode(interp, "TCL", "RESULT", "ILLEGAL_OPTIONS",
 			NULL);
 		goto error;
@@ -1440,10 +1439,9 @@ TclMergeReturnOptions(
 	     * Value is not a legal level.
 	     */
 
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "bad -level value: "
-		    "expected non-negative integer but got \"",
-		    TclGetString(valuePtr), "\"", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "bad -level value: expected non-negative integer but got"
+                    " \"%s\"", TclGetString(valuePtr)));
 	    Tcl_SetErrorCode(interp, "TCL", "RESULT", "ILLEGAL_LEVEL", NULL);
 	    goto error;
 	}
@@ -1462,10 +1460,10 @@ TclMergeReturnOptions(
 	    /*
 	     * Value is not a list, which is illegal for -errorcode.
 	     */
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "bad -errorcode value: "
-			     "expected a list but got \"",
-			     TclGetString(valuePtr), "\"", NULL);
+
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "bad -errorcode value: expected a list but got \"%s\"",
+                    TclGetString(valuePtr)));
 	    Tcl_SetErrorCode(interp, "TCL", "RESULT", "ILLEGAL_ERRORCODE",
 		    NULL);
 	    goto error;
@@ -1484,10 +1482,10 @@ TclMergeReturnOptions(
 	    /*
 	     * Value is not a list, which is illegal for -errorstack.
 	     */
-	    Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp, "bad -errorstack value: "
-		    "expected a list but got \"", TclGetString(valuePtr),
-                    "\"", NULL);
+
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "bad -errorstack value: expected a list but got \"%s\"",
+                    TclGetString(valuePtr)));
 	    Tcl_SetErrorCode(interp, "TCL", "RESULT", "NONLIST_ERRORSTACK",
                     NULL);
 	    goto error;
@@ -1496,10 +1494,10 @@ TclMergeReturnOptions(
             /*
              * Errorstack must always be an even-sized list
              */
-            Tcl_ResetResult(interp);
-	    Tcl_AppendResult(interp,
-                    "forbidden odd-sized list for -errorstack: \"",
-		    TclGetString(valuePtr), "\"", NULL);
+
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "forbidden odd-sized list for -errorstack: \"%s\"",
+		    TclGetString(valuePtr)));
 	    Tcl_SetErrorCode(interp, "TCL", "RESULT",
                     "ODDSIZEDLIST_ERRORSTACK", NULL);
 	    goto error;
@@ -1650,9 +1648,8 @@ Tcl_SetReturnOptions(
     Tcl_IncrRefCount(options);
     if (TCL_ERROR == TclListObjGetElements(interp, options, &objc, &objv)
 	    || (objc % 2)) {
-	Tcl_ResetResult(interp);
-	Tcl_AppendResult(interp, "expected dict but got \"",
-		TclGetString(options), "\"", NULL);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                "expected dict but got \"%s\"", TclGetString(options)));
 	Tcl_SetErrorCode(interp, "TCL", "RESULT", "ILLEGAL_OPTIONS", NULL);
 	code = TCL_ERROR;
     } else if (TCL_ERROR == TclMergeReturnOptions(interp, objc, objv,
diff --git a/generic/tclTimer.c b/generic/tclTimer.c
index 36adaad..6b17825 100644
--- a/generic/tclTimer.c
+++ b/generic/tclTimer.c
@@ -829,8 +829,9 @@ Tcl_AfterObjCmd(
 	if (Tcl_GetWideIntFromObj(NULL, objv[1], &ms) != TCL_OK) {
             const char *arg = Tcl_GetString(objv[1]);
 
-	    Tcl_AppendResult(interp, "bad argument \"", arg,
-		    "\": must be cancel, idle, info, or an integer", NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "bad argument \"%s\": must be"
+                    " cancel, idle, info, or an integer", arg));
             Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "argument",
                     arg, NULL);
 	    return TCL_ERROR;
@@ -968,8 +969,8 @@ Tcl_AfterObjCmd(
 	if (afterPtr == NULL) {
             const char *eventStr = TclGetString(objv[2]);
 
-	    Tcl_AppendResult(interp, "event \"", eventStr, "\" doesn't exist",
-                    NULL);
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "event \"%s\" doesn't exist", eventStr));
             Tcl_SetErrorCode(interp, "TCL","LOOKUP","EVENT", eventStr, NULL);
 	    return TCL_ERROR;
 	} else {
diff --git a/generic/tclTomMathStubLib.c b/generic/tclTomMathStubLib.c
index e7e4aea..a3bc4b3 100644
--- a/generic/tclTomMathStubLib.c
+++ b/generic/tclTomMathStubLib.c
@@ -73,10 +73,10 @@ TclTomMathInitializeStubs(
 	tclTomMathStubsPtr = stubsPtr;
 	return actualVersion;
     }
-    Tcl_ResetResult(interp);
-    Tcl_AppendResult(interp, "error loading ", packageName,
-	    " (requested version ", version, ", actual version ",
-	    actualVersion, "): ", errMsg, NULL);
+
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "error loading %s (requested version %s, actual version %s): %s",
+	    packageName, version, actualVersion, errMsg));
     return NULL;
 }
 
diff --git a/generic/tclTrace.c b/generic/tclTrace.c
index 3888549..519f201 100644
--- a/generic/tclTrace.c
+++ b/generic/tclTrace.c
@@ -366,8 +366,9 @@ Tcl_TraceObjCmd(
     return TCL_OK;
 
   badVarOps:
-    Tcl_AppendResult(interp, "bad operations \"", flagOps,
-	    "\": should be one or more of rwua", NULL);
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	    "bad operations \"%s\": should be one or more of rwua",
+	    flagOps));
     Tcl_SetErrorCode(interp, "TCL", "OPERATION", "TRACE", "BADOPS", NULL);
     return TCL_ERROR;
 }
diff --git a/tests/fileSystem.test b/tests/fileSystem.test
index 9469af0..38ecbee 100644
--- a/tests/fileSystem.test
+++ b/tests/fileSystem.test
@@ -484,7 +484,7 @@ test filesystem-6.22 {empty file name} {file pathtype ""} relative
 test filesystem-6.23 {empty file name} {file readable ""} 0
 test filesystem-6.24 {empty file name} -returnCodes error -body {
     file readlink ""
-} -result {could not readlink "": no such file or directory}
+} -result {could not read link "": no such file or directory}
 test filesystem-6.25 {empty file name} -returnCodes error -body {
     file rename "" ""
 } -result {error renaming "": no such file or directory}
diff --git a/tests/string.test b/tests/string.test
index 8cacd07..e86c0de 100644
--- a/tests/string.test
+++ b/tests/string.test
@@ -1776,10 +1776,10 @@ test string-26.3.1 {tcl::prefix, bad args} -body {
 } -returnCodes 1 -result {error options must have an even number of elements}
 test string-26.3.2 {tcl::prefix, bad args} -body {
     tcl::prefix match -error str1 str2
-} -returnCodes 1 -result {missing error options}
+} -returnCodes 1 -result {missing value for -error}
 test string-26.4 {tcl::prefix, bad args} -body {
     tcl::prefix match -message str1 str2
-} -returnCodes 1 -result {missing message}
+} -returnCodes 1 -result {missing value for -message}
 test string-26.5 {tcl::prefix} {
     tcl::prefix match {apa bepa cepa depa} cepa
 } cepa