24 files changed, 189 insertions, 163 deletions

diff --git a/doc/Encoding.3 b/doc/Encoding.3
index c801f3c..a642281 100644
--- a/doc/Encoding.3
+++ b/doc/Encoding.3
@@ -259,13 +259,13 @@ is filled with the corresponding number of bytes that were stored in
 convenience functions for converting between UTF-8 and Windows strings
 based on the TCHAR type which is by convention a Unicode character on
 Windows NT. Those functions are deprecated. You can use
-\fBTcl_UtfToUtf16DString\fR resp. \fBTcl_Utf16ToUtfDString\fR as replacement.
+\fBTcl_UtfToWCharDString\fR resp. \fBTcl_WCharToUtfDString\fR as replacement.
 If you want compatibility with earlier Tcl releases than 8.7, use
 \fBTcl_UtfToUniCharDString\fR resp. \fBTcl_UniCharToUtfDString\fR as
 replacement, and make sure you compile your extension with -DTCL_UTF_MAX=3.
 Beware: Those replacement functions don't initialize their Tcl_DString (you'll
 have to do that yourself), and \fBTcl_UniCharToUtfDString\fR doesn't accept -1
-as length parameter (but \fBTcl_Utf16ToUtfDString\fR does!).
+as length parameter (but \fBTcl_WCharToUtfDString\fR does!).
 .PP
 \fBTcl_GetEncodingName\fR is roughly the inverse of \fBTcl_GetEncoding\fR.
 Given an \fIencoding\fR, the return value is the \fIname\fR argument that
diff --git a/doc/Utf.3 b/doc/Utf.3
index fceff02..4879e79 100644
--- a/doc/Utf.3
+++ b/doc/Utf.3
@@ -8,7 +8,7 @@
 .so man.macros
 .BS
 .SH NAME
-Tcl_UniChar, Tcl_UniCharToUtf, Tcl_UtfToUniChar, Tcl_UniCharToUtfDString, Tcl_UtfToUniCharDString, Tcl_Utf16ToUtfDString, Tcl_UtfToUtf16DString, Tcl_UniCharLen, Tcl_UniCharNcmp, Tcl_UniCharNcasecmp, Tcl_UniCharCaseMatch, Tcl_UtfNcmp, Tcl_UtfNcasecmp, Tcl_UtfCharComplete, Tcl_NumUtfChars, Tcl_UtfFindFirst, Tcl_UtfFindLast, Tcl_UtfNext, Tcl_UtfPrev, Tcl_UniCharAtIndex, Tcl_UtfAtIndex, Tcl_UtfBackslash \- routines for manipulating UTF-8 strings
+Tcl_UniChar, Tcl_UniCharToUtf, Tcl_UtfToUniChar, Tcl_UniCharToUtfDString, Tcl_UtfToUniCharDString, Tcl_WCharToUtfDString, Tcl_UtfToWCharDString, Tcl_UniCharLen, Tcl_UniCharNcmp, Tcl_UniCharNcasecmp, Tcl_UniCharCaseMatch, Tcl_UtfNcmp, Tcl_UtfNcasecmp, Tcl_UtfCharComplete, Tcl_NumUtfChars, Tcl_UtfFindFirst, Tcl_UtfFindLast, Tcl_UtfNext, Tcl_UtfPrev, Tcl_UniCharAtIndex, Tcl_UtfAtIndex, Tcl_UtfBackslash \- routines for manipulating UTF-8 strings
 .SH SYNOPSIS
 .nf
 \fB#include <tcl.h>\fR
@@ -25,13 +25,13 @@ char *
 \fBTcl_UniCharToUtfDString\fR(\fIuniStr, uniLength, dsPtr\fR)
 .sp
 char *
-\fBTcl_Utf16ToUtfDString\fR(\fIutf16Str, uniLength, dsPtr\fR)
+\fBTcl_WCharToUtfDString\fR(\fIutf16Str, uniLength, dsPtr\fR)
 .sp
 Tcl_UniChar *
 \fBTcl_UtfToUniCharDString\fR(\fIsrc, length, dsPtr\fR)
 .sp
 unsigned short *
-\fBTcl_UtfToUtf16DString\fR(\fIsrc, length, dsPtr\fR)
+\fBTcl_UtfToWCharDString\fR(\fIsrc, length, dsPtr\fR)
 .sp
 int
 \fBTcl_UniCharLen\fR(\fIuniStr\fR)
diff --git a/generic/tcl.decls b/generic/tcl.decls
index bd0df8d..4fa2040 100644
--- a/generic/tcl.decls
+++ b/generic/tcl.decls
@@ -1198,7 +1198,7 @@ declare 335 {
     int Tcl_UtfToTitle(char *src)
 }
 declare 336 {
-    int Tcl_UtfToUniChar(const char *src, Tcl_UniChar *chPtr)
+    int Tcl_UtfToWChar(const char *src, unsigned short *chPtr)
 }
 declare 337 {
     int Tcl_UtfToUpper(char *src)
@@ -1253,11 +1253,11 @@ declare 353 {
 	    unsigned long numChars)
 }
 declare 354 {
-    char *Tcl_Utf16ToUtfDString(const unsigned short *uniStr,
+    char *Tcl_WCharToUtfDString(const unsigned short *uniStr,
 	    int uniLength, Tcl_DString *dsPtr)
 }
 declare 355 {
-    unsigned short *Tcl_UtfToUtf16DString(const char *src,
+    unsigned short *Tcl_UtfToWCharDString(const char *src,
 	    int length, Tcl_DString *dsPtr)
 }
 declare 356 {
@@ -2390,13 +2390,16 @@ declare 645 {
 	    int endValue, int *indexPtr)
 }
 
-# TIP #5??
+# TIP #548
+declare 646 {
+    int Tcl_UtfToUniChar(const char *src, unsigned int *chPtr)
+}
 declare 647 {
-    char *Tcl_UniCharToUtfDString(const Tcl_UniChar *uniStr,
+    char *Tcl_UniCharToUtfDString(const unsigned int *uniStr,
 	    int uniLength, Tcl_DString *dsPtr)
 }
 declare 648 {
-    Tcl_UniChar *Tcl_UtfToUniCharDString(const char *src,
+    unsigned int *Tcl_UtfToUniCharDString(const char *src,
 	    int length, Tcl_DString *dsPtr)
 }
 
diff --git a/generic/tclDecls.h b/generic/tclDecls.h
index f049bf9..9f8add6 100644
--- a/generic/tclDecls.h
+++ b/generic/tclDecls.h
@@ -1027,7 +1027,8 @@ EXTERN int		Tcl_UtfToLower(char *src);
 /* 335 */
 EXTERN int		Tcl_UtfToTitle(char *src);
 /* 336 */
-EXTERN int		Tcl_UtfToUniChar(const char *src, Tcl_UniChar *chPtr);
+EXTERN int		Tcl_UtfToWChar(const char *src,
+				unsigned short *chPtr);
 /* 337 */
 EXTERN int		Tcl_UtfToUpper(char *src);
 /* 338 */
@@ -1068,10 +1069,10 @@ EXTERN int		Tcl_UniCharNcmp(const Tcl_UniChar *ucs,
 				const Tcl_UniChar *uct,
 				unsigned long numChars);
 /* 354 */
-EXTERN char *		Tcl_Utf16ToUtfDString(const unsigned short *uniStr,
+EXTERN char *		Tcl_WCharToUtfDString(const unsigned short *uniStr,
 				int uniLength, Tcl_DString *dsPtr);
 /* 355 */
-EXTERN unsigned short *	 Tcl_UtfToUtf16DString(const char *src, int length,
+EXTERN unsigned short *	 Tcl_UtfToWCharDString(const char *src, int length,
 				Tcl_DString *dsPtr);
 /* 356 */
 EXTERN Tcl_RegExp	Tcl_GetRegExpFromObj(Tcl_Interp *interp,
@@ -1904,12 +1905,14 @@ EXTERN int		Tcl_LinkArray(Tcl_Interp *interp,
 /* 645 */
 EXTERN int		Tcl_GetIntForIndex(Tcl_Interp *interp,
 				Tcl_Obj *objPtr, int endValue, int *indexPtr);
-/* Slot 646 is reserved */
+/* 646 */
+EXTERN int		Tcl_UtfToUniChar(const char *src,
+				unsigned int *chPtr);
 /* 647 */
-EXTERN char *		Tcl_UniCharToUtfDString(const Tcl_UniChar *uniStr,
+EXTERN char *		Tcl_UniCharToUtfDString(const unsigned int *uniStr,
 				int uniLength, Tcl_DString *dsPtr);
 /* 648 */
-EXTERN Tcl_UniChar *	Tcl_UtfToUniCharDString(const char *src, int length,
+EXTERN unsigned int *	Tcl_UtfToUniCharDString(const char *src, int length,
 				Tcl_DString *dsPtr);
 
 typedef struct {
@@ -2282,7 +2285,7 @@ typedef struct TclStubs {
     char * (*tcl_UtfToExternalDString) (Tcl_Encoding encoding, const char *src, int srcLen, Tcl_DString *dsPtr); /* 333 */
     int (*tcl_UtfToLower) (char *src); /* 334 */
     int (*tcl_UtfToTitle) (char *src); /* 335 */
-    int (*tcl_UtfToUniChar) (const char *src, Tcl_UniChar *chPtr); /* 336 */
+    int (*tcl_UtfToWChar) (const char *src, unsigned short *chPtr); /* 336 */
     int (*tcl_UtfToUpper) (char *src); /* 337 */
     int (*tcl_WriteChars) (Tcl_Channel chan, const char *src, int srcLen); /* 338 */
     int (*tcl_WriteObj) (Tcl_Channel chan, Tcl_Obj *objPtr); /* 339 */
@@ -2300,8 +2303,8 @@ typedef struct TclStubs {
     int (*tcl_UniCharIsWordChar) (int ch); /* 351 */
     int (*tcl_UniCharLen) (const Tcl_UniChar *uniStr); /* 352 */
     int (*tcl_UniCharNcmp) (const Tcl_UniChar *ucs, const Tcl_UniChar *uct, unsigned long numChars); /* 353 */
-    char * (*tcl_Utf16ToUtfDString) (const unsigned short *uniStr, int uniLength, Tcl_DString *dsPtr); /* 354 */
-    unsigned short * (*tcl_UtfToUtf16DString) (const char *src, int length, Tcl_DString *dsPtr); /* 355 */
+    char * (*tcl_WCharToUtfDString) (const unsigned short *uniStr, int uniLength, Tcl_DString *dsPtr); /* 354 */
+    unsigned short * (*tcl_UtfToWCharDString) (const char *src, int length, Tcl_DString *dsPtr); /* 355 */
     Tcl_RegExp (*tcl_GetRegExpFromObj) (Tcl_Interp *interp, Tcl_Obj *patObj, int flags); /* 356 */
     TCL_DEPRECATED_API("Use Tcl_EvalTokensStandard") Tcl_Obj * (*tcl_EvalTokens) (Tcl_Interp *interp, Tcl_Token *tokenPtr, int count); /* 357 */
     void (*tcl_FreeParse) (Tcl_Parse *parsePtr); /* 358 */
@@ -2592,9 +2595,9 @@ typedef struct TclStubs {
     int (*tcl_IsShared) (Tcl_Obj *objPtr); /* 643 */
     int (*tcl_LinkArray) (Tcl_Interp *interp, const char *varName, void *addr, int type, int size); /* 644 */
     int (*tcl_GetIntForIndex) (Tcl_Interp *interp, Tcl_Obj *objPtr, int endValue, int *indexPtr); /* 645 */
-    void (*reserved646)(void);
-    char * (*tcl_UniCharToUtfDString) (const Tcl_UniChar *uniStr, int uniLength, Tcl_DString *dsPtr); /* 647 */
-    Tcl_UniChar * (*tcl_UtfToUniCharDString) (const char *src, int length, Tcl_DString *dsPtr); /* 648 */
+    int (*tcl_UtfToUniChar) (const char *src, unsigned int *chPtr); /* 646 */
+    char * (*tcl_UniCharToUtfDString) (const unsigned int *uniStr, int uniLength, Tcl_DString *dsPtr); /* 647 */
+    unsigned int * (*tcl_UtfToUniCharDString) (const char *src, int length, Tcl_DString *dsPtr); /* 648 */
 } TclStubs;
 
 extern const TclStubs *tclStubsPtr;
@@ -3297,8 +3300,8 @@ extern const TclStubs *tclStubsPtr;
 	(tclStubsPtr->tcl_UtfToLower) /* 334 */
 #define Tcl_UtfToTitle \
 	(tclStubsPtr->tcl_UtfToTitle) /* 335 */
-#define Tcl_UtfToUniChar \
-	(tclStubsPtr->tcl_UtfToUniChar) /* 336 */
+#define Tcl_UtfToWChar \
+	(tclStubsPtr->tcl_UtfToWChar) /* 336 */
 #define Tcl_UtfToUpper \
 	(tclStubsPtr->tcl_UtfToUpper) /* 337 */
 #define Tcl_WriteChars \
@@ -3333,10 +3336,10 @@ extern const TclStubs *tclStubsPtr;
 	(tclStubsPtr->tcl_UniCharLen) /* 352 */
 #define Tcl_UniCharNcmp \
 	(tclStubsPtr->tcl_UniCharNcmp) /* 353 */
-#define Tcl_Utf16ToUtfDString \
-	(tclStubsPtr->tcl_Utf16ToUtfDString) /* 354 */
-#define Tcl_UtfToUtf16DString \
-	(tclStubsPtr->tcl_UtfToUtf16DString) /* 355 */
+#define Tcl_WCharToUtfDString \
+	(tclStubsPtr->tcl_WCharToUtfDString) /* 354 */
+#define Tcl_UtfToWCharDString \
+	(tclStubsPtr->tcl_UtfToWCharDString) /* 355 */
 #define Tcl_GetRegExpFromObj \
 	(tclStubsPtr->tcl_GetRegExpFromObj) /* 356 */
 #define Tcl_EvalTokens \
@@ -3917,7 +3920,8 @@ extern const TclStubs *tclStubsPtr;
 	(tclStubsPtr->tcl_LinkArray) /* 644 */
 #define Tcl_GetIntForIndex \
 	(tclStubsPtr->tcl_GetIntForIndex) /* 645 */
-/* Slot 646 is reserved */
+#define Tcl_UtfToUniChar \
+	(tclStubsPtr->tcl_UtfToUniChar) /* 646 */
 #define Tcl_UniCharToUtfDString \
 	(tclStubsPtr->tcl_UniCharToUtfDString) /* 647 */
 #define Tcl_UtfToUniCharDString \
@@ -4109,10 +4113,13 @@ extern const TclStubs *tclStubsPtr;
 
 #if TCL_UTF_MAX <= 4
 #   undef Tcl_UniCharToUtfDString
-#   define Tcl_UniCharToUtfDString Tcl_Utf16ToUtfDString
+#   define Tcl_UniCharToUtfDString Tcl_WCharToUtfDString
 #   undef Tcl_UtfToUniCharDString
-#   define Tcl_UtfToUniCharDString Tcl_UtfToUtf16DString
+#   define Tcl_UtfToUniCharDString Tcl_UtfToWCharDString
+#	undef Tcl_UtfToUniChar
+#	define Tcl_UtfToUniChar Tcl_UtfToWChar
 #endif
+
 /*
  * Deprecated Tcl procedures:
  */
diff --git a/generic/tclIOSock.c b/generic/tclIOSock.c
index dd56c44..adf729a 100644
--- a/generic/tclIOSock.c
+++ b/generic/tclIOSock.c
@@ -35,7 +35,7 @@ gai_strerror(
 	Tcl_DStringInit(&tsdPtr->errorMsg);
 	tsdPtr->initialized = 1;
     }
-    Tcl_Utf16ToUtfDString(gai_strerrorW(code), -1, &tsdPtr->errorMsg);
+    Tcl_WCharToUtfDString(gai_strerrorW(code), -1, &tsdPtr->errorMsg);
     return Tcl_DStringValue(&tsdPtr->errorMsg);
 }
 #endif
diff --git a/generic/tclInt.h b/generic/tclInt.h
index 2031cc8..5fc3b37 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -78,12 +78,12 @@
 #else
 #include <string.h>
 #endif
-#if defined(STDC_HEADERS) || defined(__STDC__) || defined(__C99__FUNC__) \
-     || defined(__cplusplus) || defined(_MSC_VER) || defined(__ICC)
-#include <stddef.h>
-#else
+#if !defined(STDC_HEADERS) && !defined(__STDC__) && !defined(__C99__FUNC__) \
+     && !defined(__cplusplus) && !defined(_MSC_VER) && !defined(__ICC)
 typedef int ptrdiff_t;
 #endif
+#include <stddef.h>
+#include <locale.h>
 
 /*
  * Ensure WORDS_BIGENDIAN is defined correctly:
@@ -4620,10 +4620,17 @@ MODULE_SCOPE void	TclDbInitNewObj(Tcl_Obj *objPtr, const char *file,
  *----------------------------------------------------------------
  */
 
+#if TCL_UTF_MAX > 4
 #define TclUtfToUniChar(str, chPtr) \
 	((((unsigned char) *(str)) < 0x80) ?		\
 	    ((*(chPtr) = (unsigned char) *(str)), 1)	\
 	    : Tcl_UtfToUniChar(str, chPtr))
+#else
+#define TclUtfToUniChar(str, chPtr) \
+	((((unsigned char) *(str)) < 0x80) ?		\
+	    ((*(chPtr) = (unsigned char) *(str)), 1)	\
+	    : Tcl_UtfToWChar(str, chPtr))
+#endif
 
 /*
  *----------------------------------------------------------------
diff --git a/generic/tclMain.c b/generic/tclMain.c
index 8f70064..4a66793 100644
--- a/generic/tclMain.c
+++ b/generic/tclMain.c
@@ -71,7 +71,7 @@ NewNativeObj(
 
 #ifdef UNICODE
     Tcl_DStringInit(&ds);
-    Tcl_Utf16ToUtfDString(string, length, &ds);
+    Tcl_WCharToUtfDString(string, length, &ds);
 #else
     Tcl_ExternalToUtfDString(NULL, (char *) string, length, &ds);
 #endif
diff --git a/generic/tclPlatDecls.h b/generic/tclPlatDecls.h
index e35091d..0a8aff8 100644
--- a/generic/tclPlatDecls.h
+++ b/generic/tclPlatDecls.h
@@ -123,10 +123,10 @@ extern const TclPlatStubs *tclPlatStubsPtr;
 #undef Tcl_WinTCharToUtf
 #ifdef _WIN32
 #define Tcl_WinUtfToTChar(string, len, dsPtr) ((Tcl_DStringInit(dsPtr), (string) != NULL) \
-		? (TCHAR *)Tcl_UtfToUtf16DString((string), (len), (dsPtr)) \
+		? (TCHAR *)Tcl_UtfToWCharDString((string), (len), (dsPtr)) \
 		: ((void)(len), NULL))
 #define Tcl_WinTCharToUtf(string, len, dsPtr) ((Tcl_DStringInit(dsPtr), (string) != NULL) \
-		? (char *)Tcl_Utf16ToUtfDString((string), ((int)(len) >> 1), (dsPtr)) \
+		? (char *)Tcl_WCharToUtfDString((string), ((int)(len) >> 1), (dsPtr)) \
 		: ((void)(len), NULL))
 #endif
 #endif
diff --git a/generic/tclStubInit.c b/generic/tclStubInit.c
index 17076fd..7c9741a 100644
--- a/generic/tclStubInit.c
+++ b/generic/tclStubInit.c
@@ -62,17 +62,7 @@
 #define TclStaticPackage Tcl_StaticPackage
 #undef Tcl_UniCharToUtfDString
 #undef Tcl_UtfToUniCharDString
-
-#if TCL_UTF_MAX <= 4
-static void uniCodePanic() {
-    Tcl_Panic("This extension is compiled with -DTCL_UTF_MAX>4, but Tcl is compiled with -DTCL_UTF_MAX==%d", TCL_UTF_MAX);
-}
-#endif
-
-#if TCL_UTF_MAX <= 4
-#   define Tcl_UniCharToUtfDString (char *(*)(const Tcl_UniChar *, int, Tcl_DString *)) uniCodePanic
-#   define Tcl_UtfToUniCharDString (Tcl_UniChar *(*)(const char *, int, Tcl_DString *)) uniCodePanic
-#endif
+#undef Tcl_UtfToUniChar
 
 #undef TclBN_mp_tc_and
 #undef TclBN_mp_tc_or
@@ -270,7 +260,7 @@ Tcl_WinUtfToTChar(
     if (!string) {
 	return NULL;
     }
-    return (char *)Tcl_UtfToUtf16DString(string, len, dsPtr);
+    return (char *)Tcl_UtfToWCharDString(string, len, dsPtr);
 }
 #undef Tcl_WinTCharToUtf
 char *
@@ -283,7 +273,7 @@ Tcl_WinTCharToUtf(
     if (!string) {
 	return NULL;
     }
-    return Tcl_Utf16ToUtfDString((const unsigned short *)string, len >> 1, dsPtr);
+    return Tcl_WCharToUtfDString((const unsigned short *)string, len >> 1, dsPtr);
 }
 #endif /* !defined(TCL_NO_DEPRECATED) */
 
@@ -1348,7 +1338,7 @@ const TclStubs tclStubs = {
     Tcl_UtfToExternalDString, /* 333 */
     Tcl_UtfToLower, /* 334 */
     Tcl_UtfToTitle, /* 335 */
-    Tcl_UtfToUniChar, /* 336 */
+    Tcl_UtfToWChar, /* 336 */
     Tcl_UtfToUpper, /* 337 */
     Tcl_WriteChars, /* 338 */
     Tcl_WriteObj, /* 339 */
@@ -1366,8 +1356,8 @@ const TclStubs tclStubs = {
     Tcl_UniCharIsWordChar, /* 351 */
     Tcl_UniCharLen, /* 352 */
     Tcl_UniCharNcmp, /* 353 */
-    Tcl_Utf16ToUtfDString, /* 354 */
-    Tcl_UtfToUtf16DString, /* 355 */
+    Tcl_WCharToUtfDString, /* 354 */
+    Tcl_UtfToWCharDString, /* 355 */
     Tcl_GetRegExpFromObj, /* 356 */
     Tcl_EvalTokens, /* 357 */
     Tcl_FreeParse, /* 358 */
@@ -1658,7 +1648,7 @@ const TclStubs tclStubs = {
     Tcl_IsShared, /* 643 */
     Tcl_LinkArray, /* 644 */
     Tcl_GetIntForIndex, /* 645 */
-    0, /* 646 */
+    Tcl_UtfToUniChar, /* 646 */
     Tcl_UniCharToUtfDString, /* 647 */
     Tcl_UtfToUniCharDString, /* 648 */
 };
diff --git a/generic/tclTest.c b/generic/tclTest.c
index 4eb8519..4b6320b 100644
--- a/generic/tclTest.c
+++ b/generic/tclTest.c
@@ -29,11 +29,6 @@
 #include "tclRegexp.h"
 
 /*
- * Required for TestlocaleCmd
- */
-#include <locale.h>
-
-/*
  * Required for the TestChannelCmd and TestChannelEventCmd
  */
 #include "tclIO.h"
diff --git a/generic/tclUtf.c b/generic/tclUtf.c
index de696a0..7a5fb36 100644
--- a/generic/tclUtf.c
+++ b/generic/tclUtf.c
@@ -221,15 +221,15 @@ three:
  *---------------------------------------------------------------------------
  */
 
-#if TCL_UTF_MAX > 4
+#undef Tcl_UniCharToUtfDString
 char *
 Tcl_UniCharToUtfDString(
-    const Tcl_UniChar *uniStr,	/* Unicode string to convert to UTF-8. */
+    const unsigned int *uniStr,	/* Unicode string to convert to UTF-8. */
     int uniLength,		/* Length of Unicode string. */
     Tcl_DString *dsPtr)		/* UTF-8 representation of string is appended
 				 * to this previously initialized DString. */
 {
-    const Tcl_UniChar *w, *wEnd;
+    const unsigned int *w, *wEnd;
     char *p, *string;
     int oldLength;
 
@@ -259,10 +259,9 @@ Tcl_UniCharToUtfDString(
 
     return string;
 }
-#endif /* TCL_UTF_MAX > 4 */
 
 char *
-Tcl_Utf16ToUtfDString(
+Tcl_WCharToUtfDString(
     const unsigned short *uniStr,	/* Utf-16 string to convert to UTF-8. */
     int uniLength,		/* Length of Utf-16 string. */
     Tcl_DString *dsPtr)		/* UTF-8 representation of string is appended
@@ -353,13 +352,14 @@ static const unsigned short cp1252[32] = {
    0x2DC, 0x2122, 0x0161, 0x203A, 0x0153,   0x9D, 0x017E, 0x0178
 };
 
+#undef Tcl_UtfToUniChar
 int
 Tcl_UtfToUniChar(
     register const char *src,	/* The UTF-8 string. */
-    register Tcl_UniChar *chPtr)/* Filled with the Tcl_UniChar represented by
+    register unsigned int *chPtr)/* Filled with the unsigned int represented by
 				 * the UTF-8 string. */
 {
-    Tcl_UniChar byte;
+    unsigned int byte;
 
     /*
      * Unroll 1 to 4 byte UTF-8 sequences.
@@ -375,20 +375,6 @@ Tcl_UtfToUniChar(
 	 * characters representing themselves.
 	 */
 
-#if TCL_UTF_MAX <= 4
-	/* If *chPtr contains a high surrogate (produced by a previous
-	 * Tcl_UtfToUniChar() call) and the next 3 bytes are UTF-8 continuation
-	 * bytes, then we must produce a follow-up low surrogate. We only
-	 * do that if the high surrogate matches the bits we encounter.
-	 */
-	if ((byte >= 0x80)
-		&& (((((byte - 0x10) << 2) & 0xFC) | 0xD800) == (*chPtr & 0xFCFC))
-		&& ((src[1] & 0xF0) == (((*chPtr << 4) & 0x30) | 0x80))
-		&& ((src[2] & 0xC0) == 0x80)) {
-	    *chPtr = ((src[1] & 0x0F) << 6) + (src[2] & 0x3F) + 0xDC00;
-	    return 3;
-	}
-#endif
 	if ((unsigned)(byte-0x80) < (unsigned)0x20) {
 	    *chPtr = cp1252[byte-0x80];
 	} else {
@@ -434,23 +420,11 @@ Tcl_UtfToUniChar(
 	    /*
 	     * Four-byte-character lead byte followed by three trail bytes.
 	     */
-#if TCL_UTF_MAX <= 4
-	    Tcl_UniChar high = (((byte & 0x07) << 8) | ((src[1] & 0x3F) << 2)
-		    | ((src[2] & 0x3F) >> 4)) - 0x40;
-	    if (high >= 0x400) {
-		/* out of range, < 0x10000 or > 0x10ffff */
-	    } else {
-		/* produce high surrogate, advance source pointer */
-		*chPtr = 0xD800 + high;
-		return 1;
-	    }
-#else
 	    *chPtr = (((byte & 0x07) << 18) | ((src[1] & 0x3F) << 12)
 		    | ((src[2] & 0x3F) << 6) | (src[3] & 0x3F));
 	    if ((unsigned)(*chPtr - 0x10000) <= 0xFFFFF) {
 		return 4;
 	    }
-#endif
 	}
 
 	/*
@@ -463,14 +437,14 @@ Tcl_UtfToUniChar(
     return 1;
 }
 
-#if (TCL_UTF_MAX > 4) && (defined(__CYGWIN__) || defined(_WIN32))
+#undef Tcl_UtfToWChar
 int
-TclUtfToWChar(
+Tcl_UtfToWChar(
     const char *src,	/* The UTF-8 string. */
-    WCHAR *chPtr)/* Filled with the WCHAR represented by
+    unsigned short *chPtr)/* Filled with the unsigned short represented by
 				 * the UTF-8 string. */
 {
-    WCHAR byte;
+    unsigned short byte;
 
     /*
      * Unroll 1 to 4 byte UTF-8 sequences.
@@ -563,7 +537,6 @@ TclUtfToWChar(
     *chPtr = byte;
     return 1;
 }
-#endif
 
 /*
  *---------------------------------------------------------------------------
@@ -583,8 +556,8 @@ TclUtfToWChar(
  *---------------------------------------------------------------------------
  */
 
-#if TCL_UTF_MAX > 4
-Tcl_UniChar *
+#undef Tcl_UtfToUniCharDString
+unsigned int *
 Tcl_UtfToUniCharDString(
     const char *src,		/* UTF-8 string to convert to Unicode. */
     int length,			/* Length of UTF-8 string in bytes, or -1 for
@@ -593,7 +566,7 @@ Tcl_UtfToUniCharDString(
 				 * appended to this previously initialized
 				 * DString. */
 {
-    Tcl_UniChar ch = 0, *w, *wString;
+    unsigned int ch = 0, *w, *wString;
     const char *p, *end;
     int oldLength;
 
@@ -609,20 +582,20 @@ Tcl_UtfToUniCharDString(
     oldLength = Tcl_DStringLength(dsPtr);
 
     Tcl_DStringSetLength(dsPtr,
-	    oldLength + ((length + 1) * sizeof(Tcl_UniChar)));
-    wString = (Tcl_UniChar *) (Tcl_DStringValue(dsPtr) + oldLength);
+	    oldLength + ((length + 1) * sizeof(unsigned int)));
+    wString = (unsigned int *) (Tcl_DStringValue(dsPtr) + oldLength);
 
     w = wString;
     p = src;
     end = src + length - 4;
     while (p < end) {
-	p += TclUtfToUniChar(p, &ch);
+	p += Tcl_UtfToUniChar(p, &ch);
 	*w++ = ch;
     }
     end += 4;
     while (p < end) {
 	if (Tcl_UtfCharComplete(p, end-p)) {
-	    p += TclUtfToUniChar(p, &ch);
+	    p += Tcl_UtfToUniChar(p, &ch);
 	} else {
 	    ch = UCHAR(*p++);
 	}
@@ -634,10 +607,9 @@ Tcl_UtfToUniCharDString(
 
     return wString;
 }
-#endif /* TCL_UTF_MAX > 4 */
 
 unsigned short *
-Tcl_UtfToUtf16DString(
+Tcl_UtfToWCharDString(
     const char *src,		/* UTF-8 string to convert to Unicode. */
     int length,			/* Length of UTF-8 string in bytes, or -1 for
 				 * strlen(). */
@@ -645,7 +617,7 @@ Tcl_UtfToUtf16DString(
 				 * appended to this previously initialized
 				 * DString. */
 {
-    Tcl_UniChar ch = 0;
+    unsigned short ch = 0;
     unsigned short *w, *wString;
     const char *p, *end;
     int oldLength;
@@ -669,13 +641,13 @@ Tcl_UtfToUtf16DString(
     p = src;
     end = src + length - 4;
     while (p < end) {
-	p += Tcl_UtfToUniChar(p, &ch);
+	p += Tcl_UtfToWChar(p, &ch);
 	*w++ = ch;
     }
     end += 4;
     while (p < end) {
 	if (Tcl_UtfCharComplete(p, end-p)) {
-	    p += Tcl_UtfToUniChar(p, &ch);
+	    p += Tcl_UtfToWChar(p, &ch);
 	} else {
 	    ch = UCHAR(*p++);
 	}
diff --git a/generic/tclZipfs.c b/generic/tclZipfs.c
index 56f0cb9..0dca6f1 100644
--- a/generic/tclZipfs.c
+++ b/generic/tclZipfs.c
@@ -4930,7 +4930,7 @@ TclZipfs_AppHook(
 	Tcl_DString ds;
 
 	Tcl_DStringInit(&ds);
-	archive = Tcl_Utf16ToUtfDString((*argvPtr)[1], -1, &ds);
+	archive = Tcl_WCharToUtfDString((*argvPtr)[1], -1, &ds);
 #else /* !_WIN32 */
 	archive = (*argvPtr)[1];
 #endif /* _WIN32 */
diff --git a/unix/configure b/unix/configure
index 2de5b54..a35cde4 100755
--- a/unix/configure
+++ b/unix/configure
@@ -3930,6 +3930,45 @@ done
 
 
 #------------------------------------------------------------------------
+# If we're using GCC, see if the compiler understands -fshort-wchar.  If so, use it.
+# It makes sure you can use the wchar_t type interchangable with Tcl_UniChar
+#------------------------------------------------------------------------
+
+if test -z "$no_short_wchar" && test -n "$GCC"; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler understands -fshort-wchar" >&5
+$as_echo_n "checking if the compiler understands -fshort-wchar... " >&6; }
+if ${tcl_cv_cc_short_wchar+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+	hold_cflags=$CFLAGS; CFLAGS="$CFLAGS -fshort-wchar"
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  tcl_cv_cc_short_wchar=yes
+else
+  tcl_cv_cc_short_wchar=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	CFLAGS=$hold_cflags
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $tcl_cv_cc_short_wchar" >&5
+$as_echo "$tcl_cv_cc_short_wchar" >&6; }
+    if test $tcl_cv_cc_short_wchar = yes; then
+	CFLAGS="$CFLAGS -fshort-wchar"
+    fi
+fi
+
+#------------------------------------------------------------------------
 # If we're using GCC, see if the compiler understands -pipe.  If so, use it.
 # It makes compiling go faster.  (This is only a performance feature.)
 #------------------------------------------------------------------------
diff --git a/unix/configure.ac b/unix/configure.ac
index 74dbe08..3a9bdd0 100644
--- a/unix/configure.ac
+++ b/unix/configure.ac
@@ -105,6 +105,22 @@ SC_MISSING_POSIX_HEADERS
 AC_EXEEXT
 
 #------------------------------------------------------------------------
+# If we're using GCC, see if the compiler understands -fshort-wchar.  If so, use it.
+# It makes sure you can use the wchar_t type interchangable with Tcl_UniChar
+#------------------------------------------------------------------------
+
+if test -z "$no_short_wchar" && test -n "$GCC"; then
+    AC_CACHE_CHECK([if the compiler understands -fshort-wchar],
+	tcl_cv_cc_short_wchar, [
+	hold_cflags=$CFLAGS; CFLAGS="$CFLAGS -fshort-wchar"
+	AC_TRY_COMPILE(,, tcl_cv_cc_short_wchar=yes, tcl_cv_cc_short_wchar=no)
+	CFLAGS=$hold_cflags])
+    if test $tcl_cv_cc_short_wchar = yes; then
+	CFLAGS="$CFLAGS -fshort-wchar"
+    fi
+fi
+
+#------------------------------------------------------------------------
 # If we're using GCC, see if the compiler understands -pipe.  If so, use it.
 # It makes compiling go faster.  (This is only a performance feature.)
 #------------------------------------------------------------------------
diff --git a/unix/tclUnixInit.c b/unix/tclUnixInit.c
index b6b66da..187ef34 100644
--- a/unix/tclUnixInit.c
+++ b/unix/tclUnixInit.c
@@ -9,8 +9,6 @@
  */
 
 #include "tclInt.h"
-#include <stddef.h>
-#include <locale.h>
 #ifdef HAVE_LANGINFO
 #   include <langinfo.h>
 #   ifdef __APPLE__
diff --git a/unix/tclUnixTime.c b/unix/tclUnixTime.c
index 1d8b351..51d486e 100644
--- a/unix/tclUnixTime.c
+++ b/unix/tclUnixTime.c
@@ -11,7 +11,6 @@
  */
 
 #include "tclInt.h"
-#include <locale.h>
 #if defined(TCL_WIDE_CLICKS) && defined(MAC_OSX_TCL)
 #include <mach/mach_time.h>
 #endif
diff --git a/win/tclWin32Dll.c b/win/tclWin32Dll.c
index 9d927bb..6e52bd6 100644
--- a/win/tclWin32Dll.c
+++ b/win/tclWin32Dll.c
@@ -477,7 +477,7 @@ Tcl_WinUtfToTChar(
     if (!string) {
 	return NULL;
     }
-    return Tcl_UtfToUtf16DString(string, len, dsPtr);
+    return Tcl_UtfToWCharDString(string, len, dsPtr);
 }
 #undef Tcl_WinTCharToUtf
 char *
@@ -492,7 +492,7 @@ Tcl_WinTCharToUtf(
     if (!string) {
 	return NULL;
     }
-    return Tcl_Utf16ToUtfDString((unsigned short *)string, len >> 1, dsPtr);
+    return Tcl_WCharToUtfDString((unsigned short *)string, len >> 1, dsPtr);
 }
 #endif /* !defined(TCL_NO_DEPRECATED) */
 
diff --git a/win/tclWinFCmd.c b/win/tclWinFCmd.c
index b3d1ece..f8fa463 100644
--- a/win/tclWinFCmd.c
+++ b/win/tclWinFCmd.c
@@ -330,8 +330,8 @@ DoRenameFile(
 
 	    Tcl_DStringInit(&srcString);
 	    Tcl_DStringInit(&dstString);
-	    src = Tcl_Utf16ToUtfDString(nativeSrcPath, -1, &srcString);
-	    dst = Tcl_Utf16ToUtfDString(nativeDstPath, -1, &dstString);
+	    src = Tcl_WCharToUtfDString(nativeSrcPath, -1, &srcString);
+	    dst = Tcl_WCharToUtfDString(nativeDstPath, -1, &dstString);
 
 	    /*
 	     * Check whether the destination path is actually inside the
@@ -915,8 +915,8 @@ TclpObjCopyDirectory(
 
     Tcl_DStringInit(&srcString);
     Tcl_DStringInit(&dstString);
-    Tcl_UtfToUtf16DString(Tcl_GetString(normSrcPtr), -1, &srcString);
-    Tcl_UtfToUtf16DString(Tcl_GetString(normDestPtr), -1, &dstString);
+    Tcl_UtfToWCharDString(Tcl_GetString(normSrcPtr), -1, &srcString);
+    Tcl_UtfToWCharDString(Tcl_GetString(normDestPtr), -1, &dstString);
 
     ret = TraverseWinTree(TraversalCopy, &srcString, &dstString, &ds);
 
@@ -989,7 +989,7 @@ TclpObjRemoveDirectory(
 	    return TCL_ERROR;
 	}
 	Tcl_DStringInit(&native);
-	Tcl_UtfToUtf16DString(Tcl_GetString(normPtr), -1, &native);
+	Tcl_UtfToWCharDString(Tcl_GetString(normPtr), -1, &native);
 	ret = DoRemoveDirectory(&native, recursive, &ds);
 	Tcl_DStringFree(&native);
     } else {
@@ -1117,7 +1117,7 @@ DoRemoveJustDirectory(
 	char *p;
 
 	Tcl_DStringInit(errorPtr);
-	p = Tcl_Utf16ToUtfDString(nativePath, -1, errorPtr);
+	p = Tcl_WCharToUtfDString(nativePath, -1, errorPtr);
 	for (; *p; ++p) {
 	    if (*p == '\\') *p = '/';
 	}
@@ -1332,7 +1332,7 @@ TraverseWinTree(
 	TclWinConvertError(GetLastError());
 	if (errorPtr != NULL) {
 	    Tcl_DStringInit(errorPtr);
-	    Tcl_Utf16ToUtfDString(nativeErrfile, -1, errorPtr);
+	    Tcl_WCharToUtfDString(nativeErrfile, -1, errorPtr);
 	}
 	result = TCL_ERROR;
     }
@@ -1398,7 +1398,7 @@ TraversalCopy(
 
     if (errorPtr != NULL) {
 	Tcl_DStringInit(errorPtr);
-	Tcl_Utf16ToUtfDString(nativeDst, -1, errorPtr);
+	Tcl_WCharToUtfDString(nativeDst, -1, errorPtr);
     }
     return TCL_ERROR;
 }
@@ -1454,7 +1454,7 @@ TraversalDelete(
 
     if (errorPtr != NULL) {
 	Tcl_DStringInit(errorPtr);
-	Tcl_Utf16ToUtfDString(nativeSrc, -1, errorPtr);
+	Tcl_WCharToUtfDString(nativeSrc, -1, errorPtr);
     }
     return TCL_ERROR;
 }
@@ -1663,7 +1663,7 @@ ConvertFileNameFormat(
 
 	    tempString = TclGetStringFromObj(tempPath, &length);
 	    Tcl_DStringInit(&ds);
-	    nativeName = Tcl_UtfToUtf16DString(tempString, length, &ds);
+	    nativeName = Tcl_UtfToWCharDString(tempString, length, &ds);
 	    Tcl_DecrRefCount(tempPath);
 	    handle = FindFirstFile(nativeName, &data);
 	    if (handle == INVALID_HANDLE_VALUE) {
@@ -1700,7 +1700,7 @@ ConvertFileNameFormat(
 	    }
 
 	    /*
-	     * Purify reports a extraneous UMR in Tcl_Utf16ToUtfDString() trying
+	     * Purify reports a extraneous UMR in Tcl_WCharToUtfDString() trying
 	     * to dereference nativeName as a Unicode string. I have proven to
 	     * myself that purify is wrong by running the following example
 	     * when nativeName == data.w.cAlternateFileName and noting that
@@ -1712,7 +1712,7 @@ ConvertFileNameFormat(
 	     */
 
 	    Tcl_DStringInit(&dsTemp);
-	    Tcl_Utf16ToUtfDString(nativeName, -1, &dsTemp);
+	    Tcl_WCharToUtfDString(nativeName, -1, &dsTemp);
 	    Tcl_DStringFree(&ds);
 
 	    /*
@@ -2008,9 +2008,9 @@ TclpCreateTemporaryDirectory(
 	    goto useSystemTemp;
 	}
 	Tcl_DStringInit(&base);
-	Tcl_UtfToUtf16DString(Tcl_GetString(dirObj), -1, &base);
+	Tcl_UtfToWCharDString(Tcl_GetString(dirObj), -1, &base);
 	if (dirObj->bytes[dirObj->length - 1] != '\\') {
-	    Tcl_UtfToUtf16DString("\\", -1, &base);
+	    Tcl_UtfToWCharDString("\\", -1, &base);
 	}
     } else {
     useSystemTemp:
@@ -2026,11 +2026,11 @@ TclpCreateTemporaryDirectory(
 #define SUFFIX_LENGTH	8
 
     if (basenameObj) {
-	Tcl_UtfToUtf16DString(Tcl_GetString(basenameObj), -1, &base);
+	Tcl_UtfToWCharDString(Tcl_GetString(basenameObj), -1, &base);
     } else {
-	Tcl_UtfToUtf16DString(DEFAULT_TEMP_DIR_PREFIX, -1, &base);
+	Tcl_UtfToWCharDString(DEFAULT_TEMP_DIR_PREFIX, -1, &base);
     }
-    Tcl_UtfToUtf16DString("_", -1, &base);
+    Tcl_UtfToWCharDString("_", -1, &base);
 
     /*
      * Now we keep on trying random suffixes until we get one that works
@@ -2057,7 +2057,7 @@ TclpCreateTemporaryDirectory(
 	    tempbuf[i] = randChars[(int) (rand() % numRandChars)];
 	}
 	Tcl_DStringSetLength(&base, baseLen);
-	Tcl_UtfToUtf16DString(tempbuf, -1, &base);
+	Tcl_UtfToWCharDString(tempbuf, -1, &base);
     } while (!CreateDirectoryW((LPCWSTR) Tcl_DStringValue(&base), NULL)
 	    && (error = GetLastError()) == ERROR_ALREADY_EXISTS);
 
@@ -2078,7 +2078,7 @@ TclpCreateTemporaryDirectory(
      */
 
     Tcl_DStringInit(&name);
-    Tcl_Utf16ToUtfDString((LPCWSTR) Tcl_DStringValue(&base), -1, &name);
+    Tcl_WCharToUtfDString((LPCWSTR) Tcl_DStringValue(&base), -1, &name);
     Tcl_DStringFree(&base);
     return TclDStringToObj(&name);
 }
diff --git a/win/tclWinFile.c b/win/tclWinFile.c
index caf2a23..f3c45ef 100644
--- a/win/tclWinFile.c
+++ b/win/tclWinFile.c
@@ -635,7 +635,7 @@ WinReadLinkDirectory(
 	}
 
 	Tcl_DStringInit(&ds);
-	Tcl_Utf16ToUtfDString(
+	Tcl_WCharToUtfDString(
 		reparseBuffer->MountPointReparseBuffer.PathBuffer,
 		reparseBuffer->MountPointReparseBuffer
 		.SubstituteNameLength>>1, &ds);
@@ -1025,7 +1025,7 @@ TclpMatchInDirectory(
 	}
 
 	Tcl_DStringInit(&ds);
-	native = Tcl_UtfToUtf16DString(dirName, -1, &ds);
+	native = Tcl_UtfToWCharDString(dirName, -1, &ds);
 	if ((types == NULL) || (types->type != TCL_GLOB_TYPE_DIR)) {
 	    handle = FindFirstFile(native, &data);
 	} else {
@@ -1099,7 +1099,7 @@ TclpMatchInDirectory(
 	    native = data.cFileName;
 	    attr = data.dwFileAttributes;
 	    Tcl_DStringInit(&ds);
-	    utfname = Tcl_Utf16ToUtfDString(native, -1, &ds);
+	    utfname = Tcl_WCharToUtfDString(native, -1, &ds);
 
 	    if (!matchSpecialDots) {
 		/*
@@ -1474,14 +1474,14 @@ TclpGetUserHome(
 	Tcl_DStringFree(&ds);
     } else {
 	Tcl_DStringInit(&ds);
-	wName = Tcl_UtfToUtf16DString(domain + 1, -1, &ds);
+	wName = Tcl_UtfToWCharDString(domain + 1, -1, &ds);
 	rc = NetGetDCName(NULL, wName, (LPBYTE *) &wDomain);
 	Tcl_DStringFree(&ds);
 	nameLen = domain - name;
     }
     if (rc == 0) {
 	Tcl_DStringInit(&ds);
-	wName = Tcl_UtfToUtf16DString(name, nameLen, &ds);
+	wName = Tcl_UtfToWCharDString(name, nameLen, &ds);
 	while (NetUserGetInfo(wDomain, wName, 1, (LPBYTE *) &uiPtr) != 0) {
 	    /*
 	     * User does not exist; if domain was not specified, try again
@@ -1509,7 +1509,7 @@ TclpGetUserHome(
 	    wHomeDir = uiPtr->usri1_home_dir;
 	    if ((wHomeDir != NULL) && (wHomeDir[0] != '\0')) {
 		size = lstrlenW(wHomeDir);
-		Tcl_Utf16ToUtfDString(wHomeDir, size, bufferPtr);
+		Tcl_WCharToUtfDString(wHomeDir, size, bufferPtr);
 	    } else {
 		/*
 		 * User exists but has no home dir. Return
@@ -1517,7 +1517,7 @@ TclpGetUserHome(
 		 */
 
 		GetProfilesDirectoryW(buf, &size);
-		Tcl_Utf16ToUtfDString(buf, size-1, bufferPtr);
+		Tcl_WCharToUtfDString(buf, size-1, bufferPtr);
 		Tcl_DStringAppend(bufferPtr, "/", 1);
 		Tcl_DStringAppend(bufferPtr, name, nameLen);
 	    }
@@ -1986,7 +1986,7 @@ TclpGetCwd(
 	native += 2;
     }
     Tcl_DStringInit(bufferPtr);
-    Tcl_Utf16ToUtfDString(native, -1, bufferPtr);
+    Tcl_WCharToUtfDString(native, -1, bufferPtr);
 
     /*
      * Convert to forward slashes for easier use in scripts.
@@ -2195,7 +2195,7 @@ NativeDev(
 
     GetFullPathName(nativePath, MAX_PATH, nativeFullPath, &nativePart);
     Tcl_DStringInit(&ds);
-    fullPath = Tcl_Utf16ToUtfDString(nativeFullPath, -1, &ds);
+    fullPath = Tcl_WCharToUtfDString(nativeFullPath, -1, &ds);
 
     if ((fullPath[0] == '\\') && (fullPath[1] == '\\')) {
 	const char *p;
@@ -2217,7 +2217,7 @@ NativeDev(
 	    p++;
 	}
 	Tcl_DStringInit(&volString);
-	nativeVol = Tcl_UtfToUtf16DString(fullPath, p - fullPath, &volString);
+	nativeVol = Tcl_UtfToWCharDString(fullPath, p - fullPath, &volString);
 	dw = (DWORD) -1;
 	GetVolumeInformation(nativeVol, NULL, 0, &dw, NULL, NULL, NULL, 0);
 
@@ -2498,7 +2498,7 @@ TclpFilesystemPathType(
 	Tcl_DString ds;
 
 	Tcl_DStringInit(&ds);
-	Tcl_Utf16ToUtfDString(volType, -1, &ds);
+	Tcl_WCharToUtfDString(volType, -1, &ds);
 	return TclDStringToObj(&ds);
     }
 #undef VOL_BUF_SIZE
@@ -2571,7 +2571,7 @@ TclpObjNormalizePath(
 	    const WCHAR *nativePath;
 
 	    Tcl_DStringInit(&ds);
-	    nativePath = Tcl_UtfToUtf16DString(path,
+	    nativePath = Tcl_UtfToWCharDString(path,
 		    currentPathEndPosition - path, &ds);
 
 	    if (GetFileAttributesEx(nativePath,
@@ -2778,7 +2778,7 @@ TclpObjNormalizePath(
 
 	    Tcl_DStringInit(&ds);
 	    nativePath =
-		    Tcl_UtfToUtf16DString(path, lastValidPathEnd - path, &ds);
+		    Tcl_UtfToWCharDString(path, lastValidPathEnd - path, &ds);
 	    wpathlen = GetLongPathNameProc(nativePath,
 		    (WCHAR *) wpath, MAX_PATH);
 	    /*
@@ -2808,7 +2808,7 @@ TclpObjNormalizePath(
 	 */
 
 	Tcl_DStringInit(&ds);
-	Tcl_Utf16ToUtfDString((const WCHAR *) Tcl_DStringValue(&dsNorm),
+	Tcl_WCharToUtfDString((const WCHAR *) Tcl_DStringValue(&dsNorm),
 		Tcl_DStringLength(&dsNorm)>>1, &ds);
 	nextCheckpoint = Tcl_DStringLength(&ds);
 	if (*lastValidPathEnd != 0) {
@@ -2985,7 +2985,7 @@ TclpNativeToNormalized(
     char *copy, *p;
 
     Tcl_DStringInit(&ds);
-    Tcl_Utf16ToUtfDString((const WCHAR *) clientData, -1, &ds);
+    Tcl_WCharToUtfDString((const WCHAR *) clientData, -1, &ds);
     copy = Tcl_DStringValue(&ds);
     len = Tcl_DStringLength(&ds);
 
diff --git a/win/tclWinInit.c b/win/tclWinInit.c
index 4219963..117e224 100644
--- a/win/tclWinInit.c
+++ b/win/tclWinInit.c
@@ -477,7 +477,7 @@ TclpGetUserName(
 	}
 	cchUserNameLen--;
 	Tcl_DStringInit(bufferPtr);
-	Tcl_Utf16ToUtfDString(szUserName, cchUserNameLen, bufferPtr);
+	Tcl_WCharToUtfDString(szUserName, cchUserNameLen, bufferPtr);
     }
     return Tcl_DStringValue(bufferPtr);
 }
diff --git a/win/tclWinLoad.c b/win/tclWinLoad.c
index 983cfa3..ae68956 100644
--- a/win/tclWinLoad.c
+++ b/win/tclWinLoad.c
@@ -96,7 +96,7 @@ TclpDlopen(
 		ERROR_MOD_NOT_FOUND : GetLastError();
 
 	Tcl_DStringInit(&ds);
-	nativeName = Tcl_UtfToUtf16DString(Tcl_GetString(pathPtr), -1, &ds);
+	nativeName = Tcl_UtfToWCharDString(Tcl_GetString(pathPtr), -1, &ds);
 	hInstance = LoadLibraryEx(nativeName, NULL,
 		LOAD_WITH_ALTERED_SEARCH_PATH);
 	Tcl_DStringFree(&ds);
diff --git a/win/tclWinPipe.c b/win/tclWinPipe.c
index c382e23..902e01c 100644
--- a/win/tclWinPipe.c
+++ b/win/tclWinPipe.c
@@ -578,7 +578,7 @@ TclpOpenFile(
     }
 
     Tcl_DStringInit(&ds);
-    nativePath = Tcl_UtfToUtf16DString(path, -1, &ds);
+    nativePath = Tcl_UtfToWCharDString(path, -1, &ds);
 
     /*
      * If the file is not being created, use the existing file attributes.
@@ -1292,7 +1292,7 @@ ApplicationType(
 	Tcl_DStringSetLength(&nameBuf, nameLen);
 	Tcl_DStringAppend(&nameBuf, extensions[i], -1);
 	Tcl_DStringInit(&ds);
-	nativeName = Tcl_UtfToUtf16DString(Tcl_DStringValue(&nameBuf),
+	nativeName = Tcl_UtfToWCharDString(Tcl_DStringValue(&nameBuf),
 		Tcl_DStringLength(&nameBuf), &ds);
 	found = SearchPath(NULL, nativeName, NULL, MAX_PATH,
 		nativeFullPath, &rest);
@@ -1311,7 +1311,7 @@ ApplicationType(
 	    continue;
 	}
 	Tcl_DStringInit(&ds);
-	strcpy(fullName, Tcl_Utf16ToUtfDString(nativeFullPath, -1, &ds));
+	strcpy(fullName, Tcl_WCharToUtfDString(nativeFullPath, -1, &ds));
 	Tcl_DStringFree(&ds);
 
 	ext = strrchr(fullName, '.');
@@ -1403,7 +1403,7 @@ ApplicationType(
 
 	GetShortPathName(nativeFullPath, nativeFullPath, MAX_PATH);
 	Tcl_DStringInit(&ds);
-	strcpy(fullName, Tcl_Utf16ToUtfDString(nativeFullPath, -1, &ds));
+	strcpy(fullName, Tcl_WCharToUtfDString(nativeFullPath, -1, &ds));
 	Tcl_DStringFree(&ds);
     }
     return applType;
@@ -1732,7 +1732,7 @@ BuildCommandLine(
     }
     Tcl_DStringFree(linePtr);
     Tcl_DStringInit(linePtr);
-    Tcl_UtfToUtf16DString(Tcl_DStringValue(&ds), Tcl_DStringLength(&ds), linePtr);
+    Tcl_UtfToWCharDString(Tcl_DStringValue(&ds), Tcl_DStringLength(&ds), linePtr);
     Tcl_DStringFree(&ds);
 }
 
@@ -3215,7 +3215,7 @@ TclpOpenTemporaryFile(
 	const char *string = TclGetStringFromObj(basenameObj, &length);
 
 	Tcl_DStringInit(&buf);
-	Tcl_UtfToUtf16DString(string, length, &buf);
+	Tcl_UtfToWCharDString(string, length, &buf);
 	memcpy(namePtr, Tcl_DStringValue(&buf), Tcl_DStringLength(&buf));
 	namePtr += Tcl_DStringLength(&buf);
 	Tcl_DStringFree(&buf);
@@ -3236,7 +3236,7 @@ TclpOpenTemporaryFile(
 	sprintf(number, "%d.TMP", counter);
 	counter = (unsigned short) (counter + 1);
 	Tcl_DStringInit(&buf);
-	Tcl_UtfToUtf16DString(number, strlen(number), &buf);
+	Tcl_UtfToWCharDString(number, strlen(number), &buf);
 	Tcl_DStringSetLength(&buf, Tcl_DStringLength(&buf) + 1);
 	memcpy(namePtr, Tcl_DStringValue(&buf), Tcl_DStringLength(&buf) + 1);
 	Tcl_DStringFree(&buf);
diff --git a/win/tclWinSerial.c b/win/tclWinSerial.c
index 857a99f..d6fa567 100644
--- a/win/tclWinSerial.c
+++ b/win/tclWinSerial.c
@@ -1670,7 +1670,7 @@ SerialSetOptionProc(
 	    goto getStateFailed;
 	}
 	Tcl_DStringInit(&ds);
-	native = Tcl_UtfToUtf16DString(value, -1, &ds);
+	native = Tcl_UtfToWCharDString(value, -1, &ds);
 	result = BuildCommDCB(native, &dcb);
 	Tcl_DStringFree(&ds);
 
diff --git a/win/tclWinSock.c b/win/tclWinSock.c
index 8d8404e..784e2d2 100644
--- a/win/tclWinSock.c
+++ b/win/tclWinSock.c
@@ -373,7 +373,7 @@ InitializeHostName(
 	 */
 
 	Tcl_DStringInit(&ds);
-	Tcl_UtfToLower(Tcl_Utf16ToUtfDString(tbuf, -1, &ds));
+	Tcl_UtfToLower(Tcl_WCharToUtfDString(tbuf, -1, &ds));
 
     } else {
 	Tcl_DStringInit(&ds);