merge trunk

35 files changed, 1932 insertions, 1992 deletions

diff --git a/generic/tcl.h b/generic/tcl.h
index b7237bf..e557290 100644
--- a/generic/tcl.h
+++ b/generic/tcl.h
@@ -67,15 +67,12 @@ extern "C" {
  * We use this method because there is no autoconf equivalent.
  */
 
-#ifndef __WIN32__
-#   if defined(_WIN32) || defined(WIN32) || defined(__MINGW32__) || defined(__BORLANDC__) || (defined(__WATCOMC__) && defined(__WINDOWS_386__))
+#ifdef _WIN32
+#   ifndef __WIN32__
 #	define __WIN32__
-#	ifndef WIN32
-#	    define WIN32
-#	endif
-#	ifndef _WIN32
-#	    define _WIN32
-#	endif
+#   endif
+#   ifndef WIN32
+#	define WIN32
 #   endif
 #endif
 
@@ -83,11 +80,11 @@ extern "C" {
  * STRICT: See MSDN Article Q83456
  */
 
-#ifdef __WIN32__
+#ifdef _WIN32
 #   ifndef STRICT
 #	define STRICT
 #   endif
-#endif /* __WIN32__ */
+#endif /* _WIN32 */
 
 /*
  * Utility macros: STRINGIFY takes an argument and wraps it in "" (double
@@ -191,7 +188,7 @@ extern "C" {
  *       MSVCRT.
  */
 
-#if (defined(__WIN32__) && (defined(_MSC_VER) || (defined(__BORLANDC__) && (__BORLANDC__ >= 0x0550)) || defined(__LCC__) || defined(__WATCOMC__) || (defined(__GNUC__) && defined(__declspec))))
+#if (defined(_WIN32) && (defined(_MSC_VER) || (defined(__BORLANDC__) && (__BORLANDC__ >= 0x0550)) || defined(__LCC__) || defined(__WATCOMC__) || (defined(__GNUC__) && defined(__declspec))))
 #   define HAVE_DECLSPEC 1
 #   ifdef STATIC_BUILD
 #       define DLLIMPORT
@@ -315,14 +312,14 @@ extern "C" {
  * VOID. This block is skipped under Cygwin and Mingw.
  */
 
-#if defined(__WIN32__) && !defined(HAVE_WINNT_IGNORE_VOID)
+#if defined(_WIN32) && !defined(HAVE_WINNT_IGNORE_VOID)
 #ifndef VOID
 #define VOID void
 typedef char CHAR;
 typedef short SHORT;
 typedef long LONG;
 #endif
-#endif /* __WIN32__ && !HAVE_WINNT_IGNORE_VOID */
+#endif /* _WIN32 && !HAVE_WINNT_IGNORE_VOID */
 
 /*
  * Macro to use instead of "void" for arguments that must have type "void *"
@@ -390,7 +387,7 @@ typedef long LONG;
  */
 
 #if !defined(TCL_WIDE_INT_TYPE)&&!defined(TCL_WIDE_INT_IS_LONG)
-#   if defined(__WIN32__)
+#   if defined(_WIN32)
 #      define TCL_WIDE_INT_TYPE __int64
 #      ifdef __BORLANDC__
 #         define TCL_LL_MODIFIER	"L"
@@ -400,7 +397,7 @@ typedef long LONG;
 #   elif defined(__GNUC__)
 #      define TCL_WIDE_INT_TYPE long long
 #      define TCL_LL_MODIFIER	"ll"
-#   else /* ! __WIN32__ && ! __GNUC__ */
+#   else /* ! _WIN32 && ! __GNUC__ */
 /*
  * Don't know what platform it is and configure hasn't discovered what is
  * going on for us. Try to guess...
@@ -415,7 +412,7 @@ typedef long LONG;
 #	     define TCL_WIDE_INT_TYPE long long
 #         endif
 #      endif /* NO_LIMITS_H */
-#   endif /* __WIN32__ */
+#   endif /* _WIN32 */
 #endif /* !TCL_WIDE_INT_TYPE & !TCL_WIDE_INT_IS_LONG */
 #ifdef TCL_WIDE_INT_IS_LONG
 #   undef TCL_WIDE_INT_TYPE
@@ -447,7 +444,7 @@ typedef unsigned TCL_WIDE_INT_TYPE	Tcl_WideUInt;
 #   define Tcl_DoubleAsWide(val)	((Tcl_WideInt)((double)(val)))
 #endif /* TCL_WIDE_INT_IS_LONG */
 
-#if defined(__WIN32__)
+#if defined(_WIN32)
 #   ifdef __BORLANDC__
 	typedef struct stati64 Tcl_StatBuf;
 #   elif defined(_WIN64)
@@ -562,7 +559,7 @@ typedef struct Tcl_ZLibStream_ *Tcl_ZlibStream;
  * will be called as the main fuction of the new thread created by that call.
  */
 
-#if defined __WIN32__
+#if defined _WIN32
 typedef unsigned (__stdcall Tcl_ThreadCreateProc) (ClientData clientData);
 #else
 typedef void (Tcl_ThreadCreateProc) (ClientData clientData);
@@ -574,7 +571,7 @@ typedef void (Tcl_ThreadCreateProc) (ClientData clientData);
  * in generic/tclThreadTest.c for it's usage.
  */
 
-#if defined __WIN32__
+#if defined _WIN32
 #   define Tcl_ThreadCreateType		unsigned __stdcall
 #   define TCL_THREAD_CREATE_RETURN	return 0
 #else
@@ -2436,9 +2433,15 @@ EXTERN void		Tcl_GetMemoryInfo(Tcl_DString *dsPtr);
 
 /*
  * Include platform specific public function declarations that are accessible
- * via the stubs table.
+ * via the stubs table. Make all TclOO symbols MODULE_SCOPE (which only
+ * has effect on building it as a shared library). See ticket [3010352].
  */
 
+#if defined(BUILD_tcl)
+#   undef TCLAPI
+#   define TCLAPI MODULE_SCOPE
+#endif
+
 #include "tclPlatDecls.h"
 
 /*
diff --git a/generic/tclClock.c b/generic/tclClock.c
index 6d2976d..7e917f6 100644
--- a/generic/tclClock.c
+++ b/generic/tclClock.c
@@ -19,7 +19,7 @@
  * Windows has mktime. The configurators do not check.
  */
 
-#ifdef __WIN32__
+#ifdef _WIN32
 #define HAVE_MKTIME 1
 #endif
 
@@ -548,18 +548,21 @@ ClockGetjuliandayfromerayearmonthdayObjCmd(
     }
     dict = objv[1];
     if (Tcl_DictObjGet(interp, dict, literals[LIT_ERA], &fieldPtr) != TCL_OK
+		 || fieldPtr == NULL
 	    || Tcl_GetIndexFromObj(interp, fieldPtr, eras, "era", TCL_EXACT,
 		&era) != TCL_OK
-	    || Tcl_DictObjGet(interp, dict, literals[LIT_YEAR],
-		&fieldPtr) != TCL_OK
+	    || Tcl_DictObjGet(interp, dict, literals[LIT_YEAR], &fieldPtr) != TCL_OK
+		 || fieldPtr == NULL
 	    || TclGetIntFromObj(interp, fieldPtr, &fields.year) != TCL_OK
-	    || Tcl_DictObjGet(interp, dict, literals[LIT_MONTH],
-		&fieldPtr) != TCL_OK
+	    || Tcl_DictObjGet(interp, dict, literals[LIT_MONTH],	&fieldPtr) != TCL_OK
+		 || fieldPtr == NULL
 	    || TclGetIntFromObj(interp, fieldPtr, &fields.month) != TCL_OK
-	    || Tcl_DictObjGet(interp, dict, literals[LIT_DAYOFMONTH],
-		&fieldPtr) != TCL_OK
+	    || Tcl_DictObjGet(interp, dict, literals[LIT_DAYOFMONTH], &fieldPtr) != TCL_OK
+		 || fieldPtr == NULL
 	    || TclGetIntFromObj(interp, fieldPtr, &fields.dayOfMonth)!=TCL_OK
 	    || TclGetIntFromObj(interp, objv[2], &changeover) != TCL_OK) {
+    if (fieldPtr == NULL)
+	Tcl_SetObjResult(interp, Tcl_NewStringObj("expected key(s) not found in dictionary", -1));
 	return TCL_ERROR;
     }
     fields.era = era;
@@ -638,18 +641,21 @@ ClockGetjuliandayfromerayearweekdayObjCmd(
     }
     dict = objv[1];
     if (Tcl_DictObjGet(interp, dict, literals[LIT_ERA], &fieldPtr) != TCL_OK
+		 || fieldPtr == NULL
 	    || Tcl_GetIndexFromObj(interp, fieldPtr, eras, "era", TCL_EXACT,
 		&era) != TCL_OK
-	    || Tcl_DictObjGet(interp, dict, literals[LIT_ISO8601YEAR],
-		&fieldPtr) != TCL_OK
-	    || TclGetIntFromObj(interp, fieldPtr, &fields.iso8601Year)!=TCL_OK
-	    || Tcl_DictObjGet(interp, dict, literals[LIT_ISO8601WEEK],
-		&fieldPtr) != TCL_OK
-	    || TclGetIntFromObj(interp, fieldPtr, &fields.iso8601Week)!=TCL_OK
-	    || Tcl_DictObjGet(interp, dict, literals[LIT_DAYOFWEEK],
-		&fieldPtr) != TCL_OK
-	    || TclGetIntFromObj(interp, fieldPtr, &fields.dayOfWeek) != TCL_OK
+	    || Tcl_DictObjGet(interp, dict, literals[LIT_ISO8601YEAR], &fieldPtr) != TCL_OK
+		 || fieldPtr == NULL
+	    || TclGetIntFromObj(interp, fieldPtr, &(fields.iso8601Year)) != TCL_OK
+	    || Tcl_DictObjGet(interp, dict, literals[LIT_ISO8601WEEK], &fieldPtr) != TCL_OK
+		 || fieldPtr == NULL
+	    || TclGetIntFromObj(interp, fieldPtr, &(fields.iso8601Week)) != TCL_OK
+	    || Tcl_DictObjGet(interp, dict, literals[LIT_DAYOFWEEK], &fieldPtr) != TCL_OK
+		 || fieldPtr == NULL
+	    || TclGetIntFromObj(interp, fieldPtr, &(fields.dayOfWeek)) != TCL_OK
 	    || TclGetIntFromObj(interp, objv[2], &changeover) != TCL_OK) {
+    if (fieldPtr == NULL)
+	Tcl_SetObjResult(interp, Tcl_NewStringObj("expected key(s) not found in dictionary", -1));
 	return TCL_ERROR;
     }
     fields.era = era;
@@ -1697,7 +1703,7 @@ ClockClicksObjCmd(
     case 1:
 	break;
     case 2:
-	if (Tcl_GetIndexFromObj(interp, objv[1], clicksSwitches, "switch", 0,
+	if (Tcl_GetIndexFromObj(interp, objv[1], clicksSwitches, "option", 0,
 		&index) != TCL_OK) {
 	    return TCL_ERROR;
 	}
@@ -1867,9 +1873,9 @@ ClockParseformatargsObjCmd(
     localeObj = litPtr[LIT_C];
     timezoneObj = litPtr[LIT__NIL];
     for (i = 2; i < objc; i+=2) {
-	if (Tcl_GetIndexFromObj(interp, objv[i], options, "switch", 0,
+	if (Tcl_GetIndexFromObj(interp, objv[i], options, "option", 0,
 		&optionIndex) != TCL_OK) {
-	    Tcl_SetErrorCode(interp, "CLOCK", "badSwitch",
+	    Tcl_SetErrorCode(interp, "CLOCK", "badOption",
 		    Tcl_GetString(objv[i]), NULL);
 	    return TCL_ERROR;
 	}
diff --git a/generic/tclCmdAH.c b/generic/tclCmdAH.c
index f90819a..d90a747 100644
--- a/generic/tclCmdAH.c
+++ b/generic/tclCmdAH.c
@@ -1590,7 +1590,7 @@ FileAttrIsOwnedCmd(
 	 * test for equivalence to the current user.
 	 */
 
-#if defined(__WIN32__) || defined(__CYGWIN__)
+#if defined(_WIN32) || defined(__CYGWIN__)
 	value = 1;
 #else
 	value = (geteuid() == buf.st_uid);
diff --git a/generic/tclCmdIL.c b/generic/tclCmdIL.c
index 41c1eb6..db216e5 100644
--- a/generic/tclCmdIL.c
+++ b/generic/tclCmdIL.c
@@ -29,7 +29,7 @@
 typedef struct SortElement {
     union {			/* The value that we sorting by. */
 	const char *strValuePtr;
-	long intValue;
+	Tcl_WideInt wideValue;
 	double doubleValue;
 	Tcl_Obj *objValuePtr;
     } collationKey;
@@ -2893,7 +2893,8 @@ Tcl_LsearchObjCmd(
 {
     const char *bytes, *patternBytes;
     int i, match, index, result, listc, length, elemLen, bisect;
-    int dataType, isIncreasing, lower, upper, patInt, objInt, offset;
+    int dataType, isIncreasing, lower, upper, offset;
+    Tcl_WideInt patWide, objWide;
     int allMatches, inlineReturn, negatedMatch, returnSubindices, noCase;
     double patDouble, objDouble;
     SortInfo sortInfo;
@@ -3212,7 +3213,7 @@ Tcl_LsearchObjCmd(
 	    patternBytes = TclGetStringFromObj(patObj, &length);
 	    break;
 	case INTEGER:
-	    result = TclGetIntFromObj(interp, patObj, &patInt);
+	    result = TclGetWideIntFromObj(interp, patObj, &patWide);
 	    if (result != TCL_OK) {
 		goto done;
 	    }
@@ -3281,13 +3282,13 @@ Tcl_LsearchObjCmd(
 		match = DictionaryCompare(patternBytes, bytes);
 		break;
 	    case INTEGER:
-		result = TclGetIntFromObj(interp, itemPtr, &objInt);
+		result = TclGetWideIntFromObj(interp, itemPtr, &objWide);
 		if (result != TCL_OK) {
 		    goto done;
 		}
-		if (patInt == objInt) {
+		if (patWide == objWide) {
 		    match = 0;
-		} else if (patInt < objInt) {
+		} else if (patWide < objWide) {
 		    match = -1;
 		} else {
 		    match = 1;
@@ -3400,14 +3401,14 @@ Tcl_LsearchObjCmd(
 		    break;
 
 		case INTEGER:
-		    result = TclGetIntFromObj(interp, itemPtr, &objInt);
+		    result = TclGetWideIntFromObj(interp, itemPtr, &objWide);
 		    if (result != TCL_OK) {
 			if (listPtr != NULL) {
 			    Tcl_DecrRefCount(listPtr);
 			}
 			goto done;
 		    }
-		    match = (objInt == patInt);
+		    match = (objWide == patWide);
 		    break;
 
 		case REAL:
@@ -3971,13 +3972,13 @@ Tcl_LsortObjCmd(
 	if (sortMode == SORTMODE_ASCII) {
 	    elementArray[i].collationKey.strValuePtr = TclGetString(indexPtr);
 	} else if (sortMode == SORTMODE_INTEGER) {
-	    long a;
+	    Tcl_WideInt a;
 
-	    if (TclGetLongFromObj(sortInfo.interp, indexPtr, &a) != TCL_OK) {
+	    if (TclGetWideIntFromObj(sortInfo.interp, indexPtr, &a) != TCL_OK) {
 		sortInfo.resultCode = TCL_ERROR;
 		goto done1;
 	    }
-	    elementArray[i].collationKey.intValue = a;
+	    elementArray[i].collationKey.wideValue = a;
 	} else if (sortMode == SORTMODE_REAL) {
 	    double a;
 
@@ -4226,10 +4227,10 @@ SortCompare(
 	order = DictionaryCompare(elemPtr1->collationKey.strValuePtr,
 		elemPtr2->collationKey.strValuePtr);
     } else if (infoPtr->sortMode == SORTMODE_INTEGER) {
-	long a, b;
+	Tcl_WideInt a, b;
 
-	a = elemPtr1->collationKey.intValue;
-	b = elemPtr2->collationKey.intValue;
+	a = elemPtr1->collationKey.wideValue;
+	b = elemPtr2->collationKey.wideValue;
 	order = ((a >= b) - (a <= b));
     } else if (infoPtr->sortMode == SORTMODE_REAL) {
 	double a, b;
diff --git a/generic/tclCmdMZ.c b/generic/tclCmdMZ.c
index 00c9f2f..0f7f20a 100644
--- a/generic/tclCmdMZ.c
+++ b/generic/tclCmdMZ.c
@@ -161,7 +161,7 @@ Tcl_RegexpObjCmd(
 	if (name[0] != '-') {
 	    break;
 	}
-	if (Tcl_GetIndexFromObj(interp, objv[i], options, "switch", TCL_EXACT,
+	if (Tcl_GetIndexFromObj(interp, objv[i], options, "option", TCL_EXACT,
 		&index) != TCL_OK) {
 	    goto optionError;
 	}
@@ -217,7 +217,7 @@ Tcl_RegexpObjCmd(
   endOfForLoop:
     if ((objc - i) < (2 - about)) {
 	Tcl_WrongNumArgs(interp, 1, objv,
-	    "?-switch ...? exp string ?matchVar? ?subMatchVar ...?");
+		"?-option ...? exp string ?matchVar? ?subMatchVar ...?");
 	goto optionError;
     }
     objc -= i;
@@ -231,6 +231,8 @@ Tcl_RegexpObjCmd(
     if (doinline && ((objc - 2) != 0)) {
 	Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		"regexp match variables not allowed when using -inline", -1));
+	Tcl_SetErrorCode(interp, "TCL", "OPERATION", "REGEXP",
+		"MIX_VAR_INLINE", NULL);
 	goto optionError;
     }
 
@@ -519,7 +521,7 @@ Tcl_RegsubObjCmd(
 	if (name[0] != '-') {
 	    break;
 	}
-	if (Tcl_GetIndexFromObj(interp, objv[idx], options, "switch",
+	if (Tcl_GetIndexFromObj(interp, objv[idx], options, "option",
 		TCL_EXACT, &index) != TCL_OK) {
 	    goto optionError;
 	}
@@ -566,7 +568,7 @@ Tcl_RegsubObjCmd(
   endOfForLoop:
     if (objc-idx < 3 || objc-idx > 4) {
 	Tcl_WrongNumArgs(interp, 1, objv,
-		"?-switch ...? exp string subSpec ?varName?");
+		"?-option ...? exp string subSpec ?varName?");
     optionError:
 	if (startIndex) {
 	    Tcl_DecrRefCount(startIndex);
@@ -3391,7 +3393,7 @@ TclSubstOptions(
     for (i = 0; i < numOpts; i++) {
 	int optionIndex;
 
-	if (Tcl_GetIndexFromObj(interp, opts[i], substOptions, "switch", 0,
+	if (Tcl_GetIndexFromObj(interp, opts[i], substOptions, "option", 0,
 		&optionIndex) != TCL_OK) {
 	    return TCL_ERROR;
 	}
@@ -3591,7 +3593,7 @@ TclNRSwitchObjCmd(
   finishedOptions:
     if (objc - i < 2) {
 	Tcl_WrongNumArgs(interp, 1, objv,
-		"?-switch ...? string ?pattern body ...? ?default body?");
+		"?-option ...? string ?pattern body ...? ?default body?");
 	return TCL_ERROR;
     }
     if (indexVarObj != NULL && mode != OPT_REGEXP) {
@@ -3638,7 +3640,7 @@ TclNRSwitchObjCmd(
 
 	if (objc < 1) {
 	    Tcl_WrongNumArgs(interp, 1, savedObjv,
-		    "?-switch ...? string {?pattern body ...? ?default body?}");
+		    "?-option ...? string {?pattern body ...? ?default body?}");
 	    return TCL_ERROR;
 	}
 	objv = listv;
diff --git a/generic/tclDecls.h b/generic/tclDecls.h
index 830c998..91c0add 100644
--- a/generic/tclDecls.h
+++ b/generic/tclDecls.h
@@ -63,7 +63,7 @@ EXTERN void		Tcl_DbCkfree(char *ptr, const char *file, int line);
 /* 8 */
 EXTERN char *		Tcl_DbCkrealloc(char *ptr, unsigned int size,
 				const char *file, int line);
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 /* 9 */
 EXTERN void		Tcl_CreateFileHandler(int fd, int mask,
 				Tcl_FileProc *proc, ClientData clientData);
@@ -73,7 +73,7 @@ EXTERN void		Tcl_CreateFileHandler(int fd, int mask,
 EXTERN void		Tcl_CreateFileHandler(int fd, int mask,
 				Tcl_FileProc *proc, ClientData clientData);
 #endif /* MACOSX */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 /* 10 */
 EXTERN void		Tcl_DeleteFileHandler(int fd);
 #endif /* UNIX */
@@ -511,7 +511,7 @@ EXTERN Tcl_Interp *	Tcl_GetMaster(Tcl_Interp *interp);
 EXTERN const char *	Tcl_GetNameOfExecutable(void);
 /* 166 */
 EXTERN Tcl_Obj *	Tcl_GetObjResult(Tcl_Interp *interp);
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 /* 167 */
 EXTERN int		Tcl_GetOpenFile(Tcl_Interp *interp,
 				const char *chanID, int forWriting,
@@ -1835,19 +1835,19 @@ typedef struct TclStubs {
     char * (*tcl_DbCkalloc) (unsigned int size, const char *file, int line); /* 6 */
     void (*tcl_DbCkfree) (char *ptr, const char *file, int line); /* 7 */
     char * (*tcl_DbCkrealloc) (char *ptr, unsigned int size, const char *file, int line); /* 8 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     void (*tcl_CreateFileHandler) (int fd, int mask, Tcl_FileProc *proc, ClientData clientData); /* 9 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     void (*reserved9)(void);
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
     void (*tcl_CreateFileHandler) (int fd, int mask, Tcl_FileProc *proc, ClientData clientData); /* 9 */
 #endif /* MACOSX */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     void (*tcl_DeleteFileHandler) (int fd); /* 10 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     void (*reserved10)(void);
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
@@ -2009,10 +2009,10 @@ typedef struct TclStubs {
     Tcl_Interp * (*tcl_GetMaster) (Tcl_Interp *interp); /* 164 */
     const char * (*tcl_GetNameOfExecutable) (void); /* 165 */
     Tcl_Obj * (*tcl_GetObjResult) (Tcl_Interp *interp); /* 166 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     int (*tcl_GetOpenFile) (Tcl_Interp *interp, const char *chanID, int forWriting, int checkUsage, ClientData *filePtr); /* 167 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     void (*reserved167)(void);
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
@@ -2513,7 +2513,7 @@ extern const TclStubs *tclStubsPtr;
 	(tclStubsPtr->tcl_DbCkfree) /* 7 */
 #define Tcl_DbCkrealloc \
 	(tclStubsPtr->tcl_DbCkrealloc) /* 8 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 #define Tcl_CreateFileHandler \
 	(tclStubsPtr->tcl_CreateFileHandler) /* 9 */
 #endif /* UNIX */
@@ -2521,7 +2521,7 @@ extern const TclStubs *tclStubsPtr;
 #define Tcl_CreateFileHandler \
 	(tclStubsPtr->tcl_CreateFileHandler) /* 9 */
 #endif /* MACOSX */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 #define Tcl_DeleteFileHandler \
 	(tclStubsPtr->tcl_DeleteFileHandler) /* 10 */
 #endif /* UNIX */
@@ -2841,7 +2841,7 @@ extern const TclStubs *tclStubsPtr;
 	(tclStubsPtr->tcl_GetNameOfExecutable) /* 165 */
 #define Tcl_GetObjResult \
 	(tclStubsPtr->tcl_GetObjResult) /* 166 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 #define Tcl_GetOpenFile \
 	(tclStubsPtr->tcl_GetOpenFile) /* 167 */
 #endif /* UNIX */
diff --git a/generic/tclDictObj.c b/generic/tclDictObj.c
index e31d708..3c0ddd8 100644
--- a/generic/tclDictObj.c
+++ b/generic/tclDictObj.c
@@ -155,6 +155,13 @@ typedef struct Dict {
 } Dict;
 
 /*
+ * Accessor macro for converting between a Tcl_Obj* and a Dict. Note that this
+ * must be assignable as well as readable.
+ */
+
+#define DICT(dictObj)   (*((Dict **)&(dictObj)->internalRep.twoPtrValue.ptr1))
+
+/*
  * The structure below defines the dictionary object type by means of
  * functions that can be invoked by generic object code.
  */
@@ -312,6 +319,7 @@ DeleteChainEntry(
 	return 0;
     } else {
 	Tcl_Obj *valuePtr = Tcl_GetHashValue(&cPtr->entry);
+
 	TclDecrRefCount(valuePtr);
     }
 
@@ -361,7 +369,7 @@ DupDictInternalRep(
     Tcl_Obj *srcPtr,
     Tcl_Obj *copyPtr)
 {
-    Dict *oldDict = srcPtr->internalRep.twoPtrValue.ptr1;
+    Dict *oldDict = DICT(srcPtr);
     Dict *newDict = ckalloc(sizeof(Dict));
     ChainEntry *cPtr;
 
@@ -396,7 +404,7 @@ DupDictInternalRep(
      * Store in the object.
      */
 
-    copyPtr->internalRep.twoPtrValue.ptr1 = newDict;
+    DICT(copyPtr) = newDict;
     copyPtr->typePtr = &tclDictType;
 }
 
@@ -422,7 +430,7 @@ static void
 FreeDictInternalRep(
     Tcl_Obj *dictPtr)
 {
-    Dict *dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    Dict *dict = DICT(dictPtr);
 
     dict->refcount--;
     if (dict->refcount <= 0) {
@@ -487,7 +495,7 @@ UpdateStringOfDict(
 {
 #define LOCAL_SIZE 20
     int localFlags[LOCAL_SIZE], *flagPtr = NULL;
-    Dict *dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    Dict *dict = DICT(dictPtr);
     ChainEntry *cPtr;
     Tcl_Obj *keyPtr, *valuePtr;
     int i, length, bytesNeeded = 0;
@@ -600,7 +608,7 @@ SetDictFromAny(
     Tcl_Obj *objPtr)
 {
     Tcl_HashEntry *hPtr;
-    int isNew, result;
+    int isNew;
     Dict *dict = ckalloc(sizeof(Dict));
 
     InitChainTable(dict);
@@ -651,10 +659,9 @@ SetDictFromAny(
 	    const char *elemStart;
 	    int elemSize, literal;
 
-	    result = TclFindElement(interp, nextElem, (limit - nextElem),
-		    &elemStart, &nextElem, &elemSize, &literal);
-	    if (result != TCL_OK) {
-		goto errorExit;
+	    if (TclFindDictElement(interp, nextElem, (limit - nextElem),
+		    &elemStart, &nextElem, &elemSize, &literal) != TCL_OK) {
+		goto errorInFindDictElement;
 	    }
 	    if (elemStart == limit) {
 		break;
@@ -673,11 +680,10 @@ SetDictFromAny(
 			keyPtr->bytes);
 	    }
 
-	    result = TclFindElement(interp, nextElem, (limit - nextElem),
-		    &elemStart, &nextElem, &elemSize, &literal);
-	    if (result != TCL_OK) {
+	    if (TclFindDictElement(interp, nextElem, (limit - nextElem),
+		    &elemStart, &nextElem, &elemSize, &literal) != TCL_OK) {
 		TclDecrRefCount(keyPtr);
-		goto errorExit;
+		goto errorInFindDictElement;
 	    }
 
 	    if (literal) {
@@ -713,7 +719,7 @@ SetDictFromAny(
     dict->epoch = 0;
     dict->chain = NULL;
     dict->refcount = 1;
-    objPtr->internalRep.twoPtrValue.ptr1 = dict;
+    DICT(objPtr) = dict;
     objPtr->typePtr = &tclDictType;
     return TCL_OK;
 
@@ -723,15 +729,10 @@ SetDictFromAny(
 		"missing value to go with key", -1));
 	Tcl_SetErrorCode(interp, "TCL", "VALUE", "DICTIONARY", NULL);
     }
-    result = TCL_ERROR;
-
-  errorExit:
-    if (interp != NULL) {
-	Tcl_SetErrorCode(interp, "TCL", "VALUE", "DICTIONARY", NULL);
-    }
+  errorInFindDictElement:
     DeleteChainTable(dict);
     ckfree(dict);
-    return result;
+    return TCL_ERROR;
 }
 
 /*
@@ -777,12 +778,11 @@ TclTraceDictPath(
     Dict *dict, *newDict;
     int i;
 
-    if (dictPtr->typePtr != &tclDictType) {
-	if (SetDictFromAny(interp, dictPtr) != TCL_OK) {
-	    return NULL;
-	}
+    if (dictPtr->typePtr != &tclDictType
+	    && SetDictFromAny(interp, dictPtr) != TCL_OK) {
+	return NULL;
     }
-    dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    dict = DICT(dictPtr);
     if (flags & DICT_PATH_UPDATE) {
 	dict->chain = NULL;
     }
@@ -818,14 +818,13 @@ TclTraceDictPath(
 	    Tcl_SetHashValue(hPtr, tmpObj);
 	} else {
 	    tmpObj = Tcl_GetHashValue(hPtr);
-	    if (tmpObj->typePtr != &tclDictType) {
-		if (SetDictFromAny(interp, tmpObj) != TCL_OK) {
-		    return NULL;
-		}
+	    if (tmpObj->typePtr != &tclDictType
+		    && SetDictFromAny(interp, tmpObj) != TCL_OK) {
+		return NULL;
 	    }
 	}
 
-	newDict = tmpObj->internalRep.twoPtrValue.ptr1;
+	newDict = DICT(tmpObj);
 	if (flags & DICT_PATH_UPDATE) {
 	    if (Tcl_IsShared(tmpObj)) {
 		TclDecrRefCount(tmpObj);
@@ -833,7 +832,7 @@ TclTraceDictPath(
 		Tcl_IncrRefCount(tmpObj);
 		Tcl_SetHashValue(hPtr, tmpObj);
 		dict->epoch++;
-		newDict = tmpObj->internalRep.twoPtrValue.ptr1;
+		newDict = DICT(tmpObj);
 	    }
 
 	    newDict->chain = dictPtr;
@@ -868,7 +867,7 @@ static void
 InvalidateDictChain(
     Tcl_Obj *dictObj)
 {
-    Dict *dict = dictObj->internalRep.twoPtrValue.ptr1;
+    Dict *dict = DICT(dictObj);
 
     do {
 	TclInvalidateStringRep(dictObj);
@@ -878,7 +877,7 @@ InvalidateDictChain(
 	    break;
 	}
 	dict->chain = NULL;
-	dict = dictObj->internalRep.twoPtrValue.ptr1;
+	dict = DICT(dictObj);
     } while (dict != NULL);
 }
 
@@ -916,18 +915,15 @@ Tcl_DictObjPut(
 	Tcl_Panic("%s called with shared object", "Tcl_DictObjPut");
     }
 
-    if (dictPtr->typePtr != &tclDictType) {
-	int result = SetDictFromAny(interp, dictPtr);
-
-	if (result != TCL_OK) {
-	    return result;
-	}
+    if (dictPtr->typePtr != &tclDictType
+	    && SetDictFromAny(interp, dictPtr) != TCL_OK) {
+	return TCL_ERROR;
     }
 
     if (dictPtr->bytes != NULL) {
 	TclInvalidateStringRep(dictPtr);
     }
-    dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    dict = DICT(dictPtr);
     hPtr = CreateChainEntry(dict, keyPtr, &isNew);
     Tcl_IncrRefCount(valuePtr);
     if (!isNew) {
@@ -970,15 +966,13 @@ Tcl_DictObjGet(
     Dict *dict;
     Tcl_HashEntry *hPtr;
 
-    if (dictPtr->typePtr != &tclDictType) {
-	int result = SetDictFromAny(interp, dictPtr);
-	if (result != TCL_OK) {
-	    *valuePtrPtr = NULL;
-	    return result;
-	}
+    if (dictPtr->typePtr != &tclDictType
+	    && SetDictFromAny(interp, dictPtr) != TCL_OK) {
+	*valuePtrPtr = NULL;
+	return TCL_ERROR;
     }
 
-    dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    dict = DICT(dictPtr);
     hPtr = Tcl_FindHashEntry(&dict->table, keyPtr);
     if (hPtr == NULL) {
 	*valuePtrPtr = NULL;
@@ -1019,18 +1013,16 @@ Tcl_DictObjRemove(
 	Tcl_Panic("%s called with shared object", "Tcl_DictObjRemove");
     }
 
-    if (dictPtr->typePtr != &tclDictType) {
-	int result = SetDictFromAny(interp, dictPtr);
-	if (result != TCL_OK) {
-	    return result;
-	}
+    if (dictPtr->typePtr != &tclDictType
+	    && SetDictFromAny(interp, dictPtr) != TCL_OK) {
+	return TCL_ERROR;
     }
 
-    if (dictPtr->bytes != NULL) {
-	TclInvalidateStringRep(dictPtr);
-    }
-    dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    dict = DICT(dictPtr);
     if (DeleteChainEntry(dict, keyPtr)) {
+	if (dictPtr->bytes != NULL) {
+	    TclInvalidateStringRep(dictPtr);
+	}
 	dict->epoch++;
     }
     return TCL_OK;
@@ -1062,14 +1054,12 @@ Tcl_DictObjSize(
 {
     Dict *dict;
 
-    if (dictPtr->typePtr != &tclDictType) {
-	int result = SetDictFromAny(interp, dictPtr);
-	if (result != TCL_OK) {
-	    return result;
-	}
+    if (dictPtr->typePtr != &tclDictType
+	    && SetDictFromAny(interp, dictPtr) != TCL_OK) {
+	return TCL_ERROR;
     }
 
-    dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    dict = DICT(dictPtr);
     *sizePtr = dict->table.numEntries;
     return TCL_OK;
 }
@@ -1116,15 +1106,12 @@ Tcl_DictObjFirst(
     Dict *dict;
     ChainEntry *cPtr;
 
-    if (dictPtr->typePtr != &tclDictType) {
-	int result = SetDictFromAny(interp, dictPtr);
-
-	if (result != TCL_OK) {
-	    return result;
-	}
+    if (dictPtr->typePtr != &tclDictType
+	    && SetDictFromAny(interp, dictPtr) != TCL_OK) {
+	return TCL_ERROR;
     }
 
-    dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    dict = DICT(dictPtr);
     cPtr = dict->entryChainHead;
     if (cPtr == NULL) {
 	searchPtr->epoch = -1;
@@ -1299,11 +1286,12 @@ Tcl_DictObjPutKeyList(
 	return TCL_ERROR;
     }
 
-    dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    dict = DICT(dictPtr);
     hPtr = CreateChainEntry(dict, keyv[keyc-1], &isNew);
     Tcl_IncrRefCount(valuePtr);
     if (!isNew) {
 	Tcl_Obj *oldValuePtr = Tcl_GetHashValue(hPtr);
+
 	TclDecrRefCount(oldValuePtr);
     }
     Tcl_SetHashValue(hPtr, valuePtr);
@@ -1355,7 +1343,7 @@ Tcl_DictObjRemoveKeyList(
 	return TCL_ERROR;
     }
 
-    dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    dict = DICT(dictPtr);
     DeleteChainEntry(dict, keyv[keyc-1]);
     InvalidateDictChain(dictPtr);
     return TCL_OK;
@@ -1401,7 +1389,7 @@ Tcl_NewDictObj(void)
     dict->epoch = 0;
     dict->chain = NULL;
     dict->refcount = 1;
-    dictPtr->internalRep.twoPtrValue.ptr1 = dict;
+    DICT(dictPtr) = dict;
     dictPtr->typePtr = &tclDictType;
     return dictPtr;
 #endif
@@ -1450,7 +1438,7 @@ Tcl_DbNewDictObj(
     dict->epoch = 0;
     dict->chain = NULL;
     dict->refcount = 1;
-    dictPtr->internalRep.twoPtrValue.ptr1 = dict;
+    DICT(dictPtr) = dict;
     dictPtr->typePtr = &tclDictType;
     return dictPtr;
 #else /* !TCL_MEM_DEBUG */
@@ -1504,7 +1492,7 @@ DictCreateCmd(
 	/*
 	 * The next command is assumed to never fail...
 	 */
-	Tcl_DictObjPut(interp, dictObj, objv[i], objv[i+1]);
+	Tcl_DictObjPut(NULL, dictObj, objv[i], objv[i+1]);
     }
     Tcl_SetObjResult(interp, dictObj);
     return TCL_OK;
@@ -1629,8 +1617,7 @@ DictReplaceCmd(
     Tcl_Obj *const *objv)
 {
     Tcl_Obj *dictPtr;
-    int i, result;
-    int allocatedDict = 0;
+    int i;
 
     if ((objc < 2) || (objc & 1)) {
 	Tcl_WrongNumArgs(interp, 1, objv, "dictionary ?key value ...?");
@@ -1638,18 +1625,18 @@ DictReplaceCmd(
     }
 
     dictPtr = objv[1];
+    if (dictPtr->typePtr != &tclDictType
+	    && SetDictFromAny(interp, dictPtr) != TCL_OK) {
+	return TCL_ERROR;
+    }
     if (Tcl_IsShared(dictPtr)) {
 	dictPtr = Tcl_DuplicateObj(dictPtr);
-	allocatedDict = 1;
+    }
+    if (dictPtr->bytes != NULL) {
+	TclInvalidateStringRep(dictPtr);
     }
     for (i=2 ; i<objc ; i+=2) {
-	result = Tcl_DictObjPut(interp, dictPtr, objv[i], objv[i+1]);
-	if (result != TCL_OK) {
-	    if (allocatedDict) {
-		TclDecrRefCount(dictPtr);
-	    }
-	    return TCL_ERROR;
-	}
+	Tcl_DictObjPut(NULL, dictPtr, objv[i], objv[i+1]);
     }
     Tcl_SetObjResult(interp, dictPtr);
     return TCL_OK;
@@ -1681,8 +1668,7 @@ DictRemoveCmd(
     Tcl_Obj *const *objv)
 {
     Tcl_Obj *dictPtr;
-    int i, result;
-    int allocatedDict = 0;
+    int i;
 
     if (objc < 2) {
 	Tcl_WrongNumArgs(interp, 1, objv, "dictionary ?key ...?");
@@ -1690,18 +1676,18 @@ DictRemoveCmd(
     }
 
     dictPtr = objv[1];
+    if (dictPtr->typePtr != &tclDictType
+	    && SetDictFromAny(interp, dictPtr) != TCL_OK) {
+	return TCL_ERROR;
+    }
     if (Tcl_IsShared(dictPtr)) {
 	dictPtr = Tcl_DuplicateObj(dictPtr);
-	allocatedDict = 1;
+    }
+    if (dictPtr->bytes != NULL) {
+	TclInvalidateStringRep(dictPtr);
     }
     for (i=2 ; i<objc ; i++) {
-	result = Tcl_DictObjRemove(interp, dictPtr, objv[i]);
-	if (result != TCL_OK) {
-	    if (allocatedDict) {
-		TclDecrRefCount(dictPtr);
-	    }
-	    return TCL_ERROR;
-	}
+	Tcl_DictObjRemove(NULL, dictPtr, objv[i]);
     }
     Tcl_SetObjResult(interp, dictPtr);
     return TCL_OK;
@@ -1750,10 +1736,9 @@ DictMergeCmd(
      */
 
     targetObj = objv[1];
-    if (targetObj->typePtr != &tclDictType) {
-	if (SetDictFromAny(interp, targetObj) != TCL_OK) {
-	    return TCL_ERROR;
-	}
+    if (targetObj->typePtr != &tclDictType
+	    && SetDictFromAny(interp, targetObj) != TCL_OK) {
+	return TCL_ERROR;
     }
 
     if (objc == 2) {
@@ -1835,12 +1820,9 @@ DictKeysCmd(
      * need. [Bug 1705778, leak K04]
      */
 
-    if (objv[1]->typePtr != &tclDictType) {
-	int result = SetDictFromAny(interp, objv[1]);
-
-	if (result != TCL_OK) {
-	    return result;
-	}
+    if (objv[1]->typePtr != &tclDictType
+	    && SetDictFromAny(interp, objv[1]) != TCL_OK) {
+	return TCL_ERROR;
     }
 
     if (objc == 3) {
@@ -2056,13 +2038,11 @@ DictInfoCmd(
     }
 
     dictPtr = objv[1];
-    if (dictPtr->typePtr != &tclDictType) {
-	int result = SetDictFromAny(interp, dictPtr);
-	if (result != TCL_OK) {
-	    return result;
-	}
+    if (dictPtr->typePtr != &tclDictType
+	    && SetDictFromAny(interp, dictPtr) != TCL_OK) {
+	return TCL_ERROR;
     }
-    dict = dictPtr->internalRep.twoPtrValue.ptr1;
+    dict = DICT(dictPtr);
 
     statsStr = Tcl_HashStats(&dict->table);
     Tcl_SetObjResult(interp, Tcl_NewStringObj(statsStr, -1));
@@ -2099,7 +2079,7 @@ DictIncrCmd(
     Tcl_Obj *dictPtr, *valuePtr = NULL;
 
     if (objc < 3 || objc > 4) {
-	Tcl_WrongNumArgs(interp, 1, objv, "varName key ?increment?");
+	Tcl_WrongNumArgs(interp, 1, objv, "dictVarName key ?increment?");
 	return TCL_ERROR;
     }
 
@@ -2152,10 +2132,10 @@ DictIncrCmd(
 		 */
 
 		mp_clear(&increment);
-		Tcl_DictObjPut(interp, dictPtr, objv[2], objv[3]);
+		Tcl_DictObjPut(NULL, dictPtr, objv[2], objv[3]);
 	    }
 	} else {
-	    Tcl_DictObjPut(interp, dictPtr, objv[2], Tcl_NewIntObj(1));
+	    Tcl_DictObjPut(NULL, dictPtr, objv[2], Tcl_NewIntObj(1));
 	}
     } else {
 	/*
@@ -2164,7 +2144,7 @@ DictIncrCmd(
 
 	if (Tcl_IsShared(valuePtr)) {
 	    valuePtr = Tcl_DuplicateObj(valuePtr);
-	    Tcl_DictObjPut(interp, dictPtr, objv[2], valuePtr);
+	    Tcl_DictObjPut(NULL, dictPtr, objv[2], valuePtr);
 	}
 	if (objc == 4) {
 	    code = TclIncrObj(interp, valuePtr, objv[3]);
@@ -2173,7 +2153,7 @@ DictIncrCmd(
 
 	    Tcl_IncrRefCount(incrPtr);
 	    code = TclIncrObj(interp, valuePtr, incrPtr);
-	    Tcl_DecrRefCount(incrPtr);
+	    TclDecrRefCount(incrPtr);
 	}
     }
     if (code == TCL_OK) {
@@ -2186,7 +2166,7 @@ DictIncrCmd(
 	    Tcl_SetObjResult(interp, valuePtr);
 	}
     } else if (dictPtr->refCount == 0) {
-	Tcl_DecrRefCount(dictPtr);
+	TclDecrRefCount(dictPtr);
     }
     return code;
 }
@@ -2220,7 +2200,7 @@ DictLappendCmd(
     int i, allocatedDict = 0, allocatedValue = 0;
 
     if (objc < 3) {
-	Tcl_WrongNumArgs(interp, 1, objv, "varName key ?value ...?");
+	Tcl_WrongNumArgs(interp, 1, objv, "dictVarName key ?value ...?");
 	return TCL_ERROR;
     }
 
@@ -2264,7 +2244,7 @@ DictLappendCmd(
     }
 
     if (allocatedValue) {
-	Tcl_DictObjPut(interp, dictPtr, objv[2], valuePtr);
+	Tcl_DictObjPut(NULL, dictPtr, objv[2], valuePtr);
     } else if (dictPtr->bytes != NULL) {
 	TclInvalidateStringRep(dictPtr);
     }
@@ -2307,7 +2287,7 @@ DictAppendCmd(
     int i, allocatedDict = 0;
 
     if (objc < 3) {
-	Tcl_WrongNumArgs(interp, 1, objv, "varName key ?value ...?");
+	Tcl_WrongNumArgs(interp, 1, objv, "dictVarName key ?value ...?");
 	return TCL_ERROR;
     }
 
@@ -2329,17 +2309,15 @@ DictAppendCmd(
 
     if (valuePtr == NULL) {
 	TclNewObj(valuePtr);
-    } else {
-	if (Tcl_IsShared(valuePtr)) {
-	    valuePtr = Tcl_DuplicateObj(valuePtr);
-	}
+    } else if (Tcl_IsShared(valuePtr)) {
+	valuePtr = Tcl_DuplicateObj(valuePtr);
     }
 
     for (i=3 ; i<objc ; i++) {
 	Tcl_AppendObjToObj(valuePtr, objv[i]);
     }
 
-    Tcl_DictObjPut(interp, dictPtr, objv[2], valuePtr);
+    Tcl_DictObjPut(NULL, dictPtr, objv[2], valuePtr);
 
     resultPtr = Tcl_ObjSetVar2(interp, objv[1], NULL, dictPtr,
 	    TCL_LEAVE_ERR_MSG);
@@ -2383,7 +2361,7 @@ DictForNRCmd(
 
     if (objc != 4) {
 	Tcl_WrongNumArgs(interp, 1, objv,
-		"{keyVar valueVar} dictionary script");
+		"{keyVarName valueVarName} dictionary script");
 	return TCL_ERROR;
     }
 
@@ -2397,6 +2375,7 @@ DictForNRCmd(
     if (varc != 2) {
 	Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		"must have exactly two variable names", -1));
+	Tcl_SetErrorCode(interp, "TCL", "SYNTAX", "dict", "for", NULL);
 	return TCL_ERROR;
     }
     searchPtr = TclStackAlloc(interp, sizeof(Tcl_DictSearch));
@@ -2430,12 +2409,14 @@ DictForNRCmd(
      */
 
     Tcl_IncrRefCount(valueObj);
-    if (Tcl_ObjSetVar2(interp, keyVarObj, NULL, keyObj, TCL_LEAVE_ERR_MSG) == NULL) {
+    if (Tcl_ObjSetVar2(interp, keyVarObj, NULL, keyObj,
+	    TCL_LEAVE_ERR_MSG) == NULL) {
 	TclDecrRefCount(valueObj);
 	goto error;
     }
     TclDecrRefCount(valueObj);
-    if (Tcl_ObjSetVar2(interp, valueVarObj, NULL, valueObj, TCL_LEAVE_ERR_MSG) == NULL) {
+    if (Tcl_ObjSetVar2(interp, valueVarObj, NULL, valueObj,
+	    TCL_LEAVE_ERR_MSG) == NULL) {
 	goto error;
     }
 
@@ -2574,7 +2555,7 @@ DictMapNRCmd(
 
     if (objc != 4) {
 	Tcl_WrongNumArgs(interp, 1, objv,
-		"{keyVar valueVar} dictionary script");
+		"{keyVarName valueVarName} dictionary script");
 	return TCL_ERROR;
     }
 
@@ -2588,6 +2569,7 @@ DictMapNRCmd(
     if (varc != 2) {
 	Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		"must have exactly two variable names", -1));
+	Tcl_SetErrorCode(interp, "TCL", "SYNTAX", "dict", "map", NULL);
 	return TCL_ERROR;
     }
     storagePtr = TclStackAlloc(interp, sizeof(DictMapStorage));
@@ -2782,7 +2764,7 @@ DictSetCmd(
     int result, allocatedDict = 0;
 
     if (objc < 4) {
-	Tcl_WrongNumArgs(interp, 1, objv, "varName key ?key ...? value");
+	Tcl_WrongNumArgs(interp, 1, objv, "dictVarName key ?key ...? value");
 	return TCL_ERROR;
     }
 
@@ -2842,7 +2824,7 @@ DictUnsetCmd(
     int result, allocatedDict = 0;
 
     if (objc < 3) {
-	Tcl_WrongNumArgs(interp, 1, objv, "varName key ?key ...?");
+	Tcl_WrongNumArgs(interp, 1, objv, "dictVarName key ?key ...?");
 	return TCL_ERROR;
     }
 
@@ -2949,12 +2931,12 @@ DictFilterCmd(
 		Tcl_DictObjDone(&search);
 		Tcl_DictObjGet(interp, objv[1], objv[3], &valueObj);
 		if (valueObj != NULL) {
-		    Tcl_DictObjPut(interp, resultObj, objv[3], valueObj);
+		    Tcl_DictObjPut(NULL, resultObj, objv[3], valueObj);
 		}
 	    } else {
 		while (!done) {
 		    if (Tcl_StringMatch(TclGetString(keyObj), pattern)) {
-			Tcl_DictObjPut(interp, resultObj, keyObj, valueObj);
+			Tcl_DictObjPut(NULL, resultObj, keyObj, valueObj);
 		    }
 		    Tcl_DictObjNext(&search, &keyObj, &valueObj, &done);
 		}
@@ -2972,7 +2954,7 @@ DictFilterCmd(
 		for (i=3 ; i<objc ; i++) {
 		    pattern = TclGetString(objv[i]);
 		    if (Tcl_StringMatch(TclGetString(keyObj), pattern)) {
-			Tcl_DictObjPut(interp, resultObj, keyObj, valueObj);
+			Tcl_DictObjPut(NULL, resultObj, keyObj, valueObj);
 			break;		/* stop inner loop */
 		    }
 		}
@@ -2998,7 +2980,7 @@ DictFilterCmd(
 	    for (i=3 ; i<objc ; i++) {
 		pattern = TclGetString(objv[i]);
 		if (Tcl_StringMatch(TclGetString(valueObj), pattern)) {
-		    Tcl_DictObjPut(interp, resultObj, keyObj, valueObj);
+		    Tcl_DictObjPut(NULL, resultObj, keyObj, valueObj);
 		    break;		/* stop inner loop */
 		}
 	    }
@@ -3010,7 +2992,7 @@ DictFilterCmd(
     case FILTER_SCRIPT:
 	if (objc != 5) {
 	    Tcl_WrongNumArgs(interp, 1, objv,
-		    "dictionary script {keyVar valueVar} filterScript");
+		    "dictionary script {keyVarName valueVarName} filterScript");
 	    return TCL_ERROR;
 	}
 
@@ -3026,6 +3008,7 @@ DictFilterCmd(
 	if (varc != 2) {
 	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		    "must have exactly two variable names", -1));
+	    Tcl_SetErrorCode(interp, "TCL", "SYNTAX", "dict", "filter", NULL);
 	    return TCL_ERROR;
 	}
 	keyVarObj = varv[0];
@@ -3064,19 +3047,15 @@ DictFilterCmd(
 	    Tcl_IncrRefCount(valueObj);
 	    if (Tcl_ObjSetVar2(interp, keyVarObj, NULL, keyObj,
 		    TCL_LEAVE_ERR_MSG) == NULL) {
-		Tcl_ResetResult(interp);
-		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
-			"couldn't set key variable: \"%s\"",
-			TclGetString(keyVarObj)));
+		Tcl_AddErrorInfo(interp, 
+			"\n    (\"dict filter\" filter script key variable)");
 		result = TCL_ERROR;
 		goto abnormalResult;
 	    }
 	    if (Tcl_ObjSetVar2(interp, valueVarObj, NULL, valueObj,
 		    TCL_LEAVE_ERR_MSG) == NULL) {
-		Tcl_ResetResult(interp);
-		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
-			"couldn't set value variable: \"%s\"",
-			TclGetString(valueVarObj)));
+		Tcl_AddErrorInfo(interp, 
+			"\n    (\"dict filter\" filter script value variable)");
 		result = TCL_ERROR;
 		goto abnormalResult;
 	    }
@@ -3099,7 +3078,7 @@ DictFilterCmd(
 		}
 		TclDecrRefCount(boolObj);
 		if (satisfied) {
-		    Tcl_DictObjPut(interp, resultObj, keyObj, valueObj);
+		    Tcl_DictObjPut(NULL, resultObj, keyObj, valueObj);
 		}
 		break;
 	    case TCL_BREAK:
@@ -3190,7 +3169,7 @@ DictUpdateCmd(
 
     if (objc < 5 || !(objc & 1)) {
 	Tcl_WrongNumArgs(interp, 1, objv,
-		"varName key varName ?key varName ...? script");
+		"dictVarName key varName ?key varName ...? script");
 	return TCL_ERROR;
     }
 
@@ -3287,18 +3266,17 @@ FinalizeDictUpdate(
     for (i=0 ; i<objc ; i+=2) {
 	objPtr = Tcl_ObjGetVar2(interp, objv[i+1], NULL, 0);
 	if (objPtr == NULL) {
-	    Tcl_DictObjRemove(interp, dictPtr, objv[i]);
+	    Tcl_DictObjRemove(NULL, dictPtr, objv[i]);
 	} else if (objPtr == dictPtr) {
 	    /*
 	     * Someone is messing us around, trying to build a recursive
 	     * structure. [Bug 1786481]
 	     */
 
-	    Tcl_DictObjPut(interp, dictPtr, objv[i],
-		    Tcl_DuplicateObj(objPtr));
+	    Tcl_DictObjPut(NULL, dictPtr, objv[i], Tcl_DuplicateObj(objPtr));
 	} else {
 	    /* Shouldn't fail */
-	    Tcl_DictObjPut(interp, dictPtr, objv[i], objPtr);
+	    Tcl_DictObjPut(NULL, dictPtr, objv[i], objPtr);
 	}
     }
     TclDecrRefCount(argsObj);
@@ -3347,7 +3325,7 @@ DictWithCmd(
     Tcl_Obj *dictPtr, *keysPtr, *pathPtr;
 
     if (objc < 3) {
-	Tcl_WrongNumArgs(interp, 1, objv, "dictVar ?key ...? script");
+	Tcl_WrongNumArgs(interp, 1, objv, "dictVarName ?key ...? script");
 	return TCL_ERROR;
     }
 
diff --git a/generic/tclEnsemble.c b/generic/tclEnsemble.c
index 9bb7a0c..022dafa 100644
--- a/generic/tclEnsemble.c
+++ b/generic/tclEnsemble.c
@@ -2751,13 +2751,6 @@ TclCompileEnsemble(
     const char *word;
 
     Tcl_IncrRefCount(replaced);
-
-    /*
-     * This is where we return to if we are parsing multiple nested compiled
-     * ensembles. [info object] is such a beast.
-     */
-
-  checkNextWord:
     if (parsePtr->numWords < depth + 1) {
 	goto failed;
     }
@@ -2769,6 +2762,12 @@ TclCompileEnsemble(
 	goto failed;
     }
 
+    /*
+     * This is where we return to if we are parsing multiple nested compiled
+     * ensembles. [info object] is such a beast.
+     */
+
+  checkNextWord:
     word = tokenPtr[1].start;
     numBytes = tokenPtr[1].size;
 
@@ -2979,6 +2978,17 @@ TclCompileEnsemble(
 
     if (cmdPtr->compileProc == TclCompileEnsemble) {
 	tokenPtr = TokenAfter(tokenPtr);
+	if (parsePtr->numWords < depth + 1
+		|| tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
+	    /*
+	     * Too hard because the user has done something unpleasant like
+	     * omitting the sub-ensemble's command name or used a non-constant
+	     * name for a sub-ensemble's command name; we respond by bailing
+	     * out completely (this is a rare case). [Bug 6d2f249a01]
+	     */
+
+	    goto cleanup;
+	}
 	ensemble = (Tcl_Command) cmdPtr;
 	goto checkNextWord;
     }
diff --git a/generic/tclEnv.c b/generic/tclEnv.c
index 8f51c1b..cd1a954 100644
--- a/generic/tclEnv.c
+++ b/generic/tclEnv.c
@@ -444,7 +444,7 @@ TclUnsetEnv(
      * that no = should be included, and Windows requires it.
      */
 
-#if defined(__WIN32__) || defined(__CYGWIN__)
+#if defined(_WIN32) || defined(__CYGWIN__)
     string = ckalloc(length + 2);
     memcpy(string, name, (size_t) length);
     string[length] = '=';
@@ -453,7 +453,7 @@ TclUnsetEnv(
     string = ckalloc(length + 1);
     memcpy(string, name, (size_t) length);
     string[length] = '\0';
-#endif /* WIN32 */
+#endif /* _WIN32 */
 
     Tcl_UtfToExternalDString(NULL, string, -1, &envString);
     string = ckrealloc(string, Tcl_DStringLength(&envString) + 1);
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 89305e6..d8c5935 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -556,30 +556,6 @@ VarHashCreateVar(
 	: Tcl_GetBooleanFromObj((interp), (objPtr), (boolPtr)))
 
 /*
- * Macro used in this file to save a function call for common uses of
- * Tcl_GetWideIntFromObj(). The ANSI C "prototype" is:
- *
- * MODULE_SCOPE int TclGetWideIntFromObj(Tcl_Interp *interp, Tcl_Obj *objPtr,
- *			Tcl_WideInt *wideIntPtr);
- */
-
-#ifdef TCL_WIDE_INT_IS_LONG
-#define TclGetWideIntFromObj(interp, objPtr, wideIntPtr) \
-    (((objPtr)->typePtr == &tclIntType)					\
-	? (*(wideIntPtr) = (Tcl_WideInt)				\
-		((objPtr)->internalRep.longValue), TCL_OK) :		\
-	Tcl_GetWideIntFromObj((interp), (objPtr), (wideIntPtr)))
-#else /* !TCL_WIDE_INT_IS_LONG */
-#define TclGetWideIntFromObj(interp, objPtr, wideIntPtr)		\
-    (((objPtr)->typePtr == &tclWideIntType)				\
-	? (*(wideIntPtr) = (objPtr)->internalRep.wideValue, TCL_OK) :	\
-    ((objPtr)->typePtr == &tclIntType)					\
-	? (*(wideIntPtr) = (Tcl_WideInt)				\
-		((objPtr)->internalRep.longValue), TCL_OK) :		\
-	Tcl_GetWideIntFromObj((interp), (objPtr), (wideIntPtr)))
-#endif /* TCL_WIDE_INT_IS_LONG */
-
-/*
  * Macro used to make the check for type overflow more mnemonic. This works by
  * comparing sign bits; the rest of the word is irrelevant. The ANSI C
  * "prototype" (where inttype_t is any integer type) is:
@@ -5392,6 +5368,7 @@ TEBCresume(
 	} else {
 	    length = Tcl_UtfToUpper(TclGetString(valuePtr));
 	    Tcl_SetObjLength(valuePtr, length);
+	    TclFreeIntRep(valuePtr);
 	    TRACE_APPEND(("\"%.20s\"\n", O2S(valuePtr)));
 	    NEXT_INST_F(1, 0, 0);
 	}
@@ -5408,6 +5385,7 @@ TEBCresume(
 	} else {
 	    length = Tcl_UtfToLower(TclGetString(valuePtr));
 	    Tcl_SetObjLength(valuePtr, length);
+	    TclFreeIntRep(valuePtr);
 	    TRACE_APPEND(("\"%.20s\"\n", O2S(valuePtr)));
 	    NEXT_INST_F(1, 0, 0);
 	}
@@ -5424,6 +5402,7 @@ TEBCresume(
 	} else {
 	    length = Tcl_UtfToTitle(TclGetString(valuePtr));
 	    Tcl_SetObjLength(valuePtr, length);
+	    TclFreeIntRep(valuePtr);
 	    TRACE_APPEND(("\"%.20s\"\n", O2S(valuePtr)));
 	    NEXT_INST_F(1, 0, 0);
 	}
@@ -5699,11 +5678,21 @@ TEBCresume(
 			length - toIdx);
 	    }
 	} else {
-	    objResultPtr = value3Ptr;
+	    /*
+	     * Be careful with splicing the stack in this case; we have a
+	     * refCount:1 object in value3Ptr and we want to append to it and
+	     * make it be the refCount:1 object at the top of the stack
+	     * afterwards. [Bug 82e7f67325]
+	     */
+
 	    if (toIdx < length) {
-		Tcl_AppendUnicodeToObj(objResultPtr, ustring1 + toIdx + 1,
+		Tcl_AppendUnicodeToObj(value3Ptr, ustring1 + toIdx + 1,
 			length - toIdx);
 	    }
+	    TRACE_APPEND(("\"%.30s\"\n", O2S(value3Ptr)));
+	    TclDecrRefCount(valuePtr);
+	    OBJ_AT_TOS = value3Ptr;	/* Tricky! */
+	    NEXT_INST_F(1, 0, 0);
 	}
 	TclDecrRefCount(value3Ptr);
 	TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
@@ -5986,6 +5975,31 @@ TEBCresume(
     case INST_NUM_TYPE:
 	if (GetNumberFromObj(NULL, OBJ_AT_TOS, &ptr1, &type1) != TCL_OK) {
 	    type1 = 0;
+	} else if (type1 == TCL_NUMBER_LONG) {
+	    /* value is between LONG_MIN and LONG_MAX */
+	    /* [string is integer] is -UINT_MAX to UINT_MAX range */
+	    int i;
+
+	    if (Tcl_GetIntFromObj(NULL, OBJ_AT_TOS, &i) != TCL_OK) {
+		type1 = TCL_NUMBER_WIDE;
+	    }
+#ifndef TCL_WIDE_INT_IS_LONG
+	} else if (type1 == TCL_NUMBER_WIDE) {
+	    /* value is between WIDE_MIN and WIDE_MAX */
+	    /* [string is wideinteger] is -UWIDE_MAX to UWIDE_MAX range */
+	    int i;
+	    if (Tcl_GetIntFromObj(NULL, OBJ_AT_TOS, &i) == TCL_OK) {
+		type1 = TCL_NUMBER_LONG;
+	    }
+#endif
+	} else if (type1 == TCL_NUMBER_BIG) {
+	    /* value is an integer outside the WIDE_MIN to WIDE_MAX range */
+	    /* [string is wideinteger] is -UWIDE_MAX to UWIDE_MAX range */
+	    Tcl_WideInt w;
+
+	    if (Tcl_GetWideIntFromObj(NULL, OBJ_AT_TOS, &w) == TCL_OK) {
+		type1 = TCL_NUMBER_WIDE;
+	    }
 	}
 	TclNewIntObj(objResultPtr, type1);
 	TRACE(("\"%.20s\" => %d\n", O2S(OBJ_AT_TOS), type1));
diff --git a/generic/tclFCmd.c b/generic/tclFCmd.c
index 13377d3..8bf0a5a 100644
--- a/generic/tclFCmd.c
+++ b/generic/tclFCmd.c
@@ -517,7 +517,7 @@ CopyRenameOneFile(
 	 * 16 bits and we get collisions. See bug #2015723.
 	 */
 
-#if !defined(WIN32) && !defined(__CYGWIN__)
+#if !defined(_WIN32) && !defined(__CYGWIN__)
 	if ((sourceStatBuf.st_ino != 0) && (targetStatBuf.st_ino != 0)) {
 	    if ((sourceStatBuf.st_ino == targetStatBuf.st_ino) &&
 		    (sourceStatBuf.st_dev == targetStatBuf.st_dev)) {
@@ -1196,7 +1196,7 @@ TclFileLinkCmd(
 	    static const char *const linkTypes[] = {
 		"-symbolic", "-hard", NULL
 	    };
-	    if (Tcl_GetIndexFromObj(interp, objv[1], linkTypes, "switch", 0,
+	    if (Tcl_GetIndexFromObj(interp, objv[1], linkTypes, "option", 0,
 		    &linkAction) != TCL_OK) {
 		return TCL_ERROR;
 	    }
diff --git a/generic/tclIO.c b/generic/tclIO.c
index ff975c3..c8c9aec 100644
--- a/generic/tclIO.c
+++ b/generic/tclIO.c
@@ -6,6 +6,7 @@
  *
  * Copyright (c) 1998-2000 Ajuba Solutions
  * Copyright (c) 1995-1997 Sun Microsystems, Inc.
+ * Contributions from Don Porter, NIST, 2014. (not subject to US copyright)
  *
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
@@ -162,7 +163,11 @@ typedef struct CloseCallback {
  */
 
 static ChannelBuffer *	AllocChannelBuffer(int length);
+static void		PreserveChannelBuffer(ChannelBuffer *bufPtr);
+static void		ReleaseChannelBuffer(ChannelBuffer *bufPtr);
+static int		IsShared(ChannelBuffer *bufPtr);
 static void		ChannelTimerProc(ClientData clientData);
+static int		ChanRead(Channel *chanPtr, char *dst, int dstSize);
 static int		CheckChannelErrors(ChannelState *statePtr,
 			    int direction);
 static int		CheckForDeadChannel(Tcl_Interp *interp,
@@ -176,9 +181,6 @@ static int		CloseChannelPart(Tcl_Interp *interp, Channel *chanPtr,
 			    int errorCode, int flags);
 static int		CloseWrite(Tcl_Interp *interp, Channel *chanPtr);
 static void		CommonGetsCleanup(Channel *chanPtr);
-static int		CopyAndTranslateBuffer(ChannelState *statePtr,
-			    char *result, int space);
-static int		CopyBuffer(Channel *chanPtr, char *result, int space);
 static int		CopyData(CopyState *csPtr, int mask);
 static void		CopyEventProc(ClientData clientData, int mask);
 static void		CreateScriptRecord(Tcl_Interp *interp,
@@ -191,7 +193,8 @@ static int		DetachChannel(Tcl_Interp *interp, Tcl_Channel chan);
 static void		DiscardInputQueued(ChannelState *statePtr,
 			    int discardSavedBuffers);
 static void		DiscardOutputQueued(ChannelState *chanPtr);
-static int		DoRead(Channel *chanPtr, char *srcPtr, int slen, int allowShortReads);
+static int		DoRead(Channel *chanPtr, char *dst, int bytesToRead,
+			    int allowShortReads);
 static int		DoReadChars(Channel *chan, Tcl_Obj *objPtr, int toRead,
 			    int appendFlag);
 static int		FilterInputBytes(Channel *chanPtr,
@@ -208,16 +211,16 @@ static int		HaveVersion(const Tcl_ChannelType *typePtr,
 static void		PeekAhead(Channel *chanPtr, char **dstEndPtr,
 			    GetsState *gsPtr);
 static int		ReadBytes(ChannelState *statePtr, Tcl_Obj *objPtr,
-			    int charsLeft, int *offsetPtr);
+			    int charsLeft);
 static int		ReadChars(ChannelState *statePtr, Tcl_Obj *objPtr,
-			    int charsLeft, int *offsetPtr, int *factorPtr);
+			    int charsLeft, int *factorPtr);
 static void		RecycleBuffer(ChannelState *statePtr,
 			    ChannelBuffer *bufPtr, int mustDiscard);
 static int		StackSetBlockMode(Channel *chanPtr, int mode);
 static int		SetBlockMode(Tcl_Interp *interp, Channel *chanPtr,
 			    int mode);
 static void		StopCopy(CopyState *csPtr);
-static int		TranslateInputEOL(ChannelState *statePtr, char *dst,
+static void		TranslateInputEOL(ChannelState *statePtr, char *dst,
 			    const char *src, int *dstLenPtr, int *srcLenPtr);
 static void		UpdateInterest(Channel *chanPtr);
 static int		Write(Channel *chanPtr, const char *src,
@@ -284,7 +287,7 @@ static int              WillRead(Channel *chanPtr);
 
 #define IsBufferEmpty(bufPtr)	((bufPtr)->nextAdded == (bufPtr)->nextRemoved)
 
-#define IsBufferFull(bufPtr)	((bufPtr)->nextAdded >= (bufPtr)->bufLength)
+#define IsBufferFull(bufPtr)	((bufPtr) && (bufPtr)->nextAdded >= (bufPtr)->bufLength)
 
 #define IsBufferOverflowing(bufPtr) ((bufPtr)->nextAdded>(bufPtr)->bufLength)
 
@@ -379,19 +382,79 @@ ChanCloseHalf(
     return chanPtr->typePtr->close2Proc(chanPtr->instanceData, interp, flags);
 }
 
-static inline int
+/*
+ *---------------------------------------------------------------------------
+ *
+ * ChanRead --
+ *
+ *	Read up to dstSize bytes using the inputProc of chanPtr, store
+ *	them at dst, and return the number of bytes stored.
+ *
+ * Results:
+ *	The return value of the driver inputProc,
+ *	  - number of bytes stored at dst, ot
+ *	  - -1 on error, with a Posix error code available to the
+ *	    caller by calling Tcl_GetErrno().
+ *
+ * Side effects:
+ *	The CHANNEL_BLOCKED and CHANNEL_EOF flags of the channel state are
+ *	set as appropriate.
+ *	On EOF, the inputEncodingFlags are set to perform ending operations
+ *	on decoding.
+ *	TODO - Is this really the right place for that?
+ *
+ *---------------------------------------------------------------------------
+ */
+static int
 ChanRead(
     Channel *chanPtr,
     char *dst,
-    int dstSize,
-    int *errnoPtr)
+    int dstSize)
 {
+    int bytesRead, result;
+
+    /*
+     * If the caller asked for zero bytes, we'd force the inputProc
+     * to return zero bytes, and then misinterpret that as EOF.
+     */
+    assert(dstSize > 0);
+
+    /*
+     * Each read op must set the blocked and eof states anew, not let
+     * the effect of prior reads leak through.
+     */
+    ResetFlag(chanPtr->state, CHANNEL_BLOCKED | CHANNEL_EOF);
     if (WillRead(chanPtr) < 0) {
         return -1;
     }
 
-    return chanPtr->typePtr->inputProc(chanPtr->instanceData, dst, dstSize,
-	    errnoPtr);
+    bytesRead = chanPtr->typePtr->inputProc(chanPtr->instanceData,
+	    dst, dstSize, &result);
+
+    /* Stop any flag leakage through stacked channel levels */
+    ResetFlag(chanPtr->state, CHANNEL_BLOCKED | CHANNEL_EOF);
+    if (bytesRead > 0) {
+	/*
+	 * If we get a short read, signal up that we may be BLOCKED.
+	 * We should avoid calling the driver because on some
+	 * platforms we will block in the low level reading code even
+	 * though the channel is set into nonblocking mode.
+	 */
+
+	if (bytesRead < dstSize) {
+	    SetFlag(chanPtr->state, CHANNEL_BLOCKED);
+	}
+    } else if (bytesRead == 0) {
+	SetFlag(chanPtr->state, CHANNEL_EOF);
+	chanPtr->state->inputEncodingFlags |= TCL_ENCODING_END;
+    } else if (bytesRead < 0) {
+	if ((result == EWOULDBLOCK) || (result == EAGAIN)) {
+	    SetFlag(chanPtr->state, CHANNEL_BLOCKED);
+	    result = EAGAIN;
+	}
+	Tcl_SetErrno(result);
+    }
+    return bytesRead;
 }
 
 static inline Tcl_WideInt
@@ -1174,15 +1237,6 @@ Tcl_UnregisterChannel(
      */
 
     if (statePtr->refCount <= 0) {
-	/*
-	 * Ensure that if there is another buffer, it gets flushed whether or
-	 * not we are doing a background flush.
-	 */
-
-	if ((statePtr->curOutPtr != NULL) &&
-		IsBufferReady(statePtr->curOutPtr)) {
-	    SetFlag(statePtr, BUFFER_READY);
-	}
 	Tcl_Preserve(statePtr);
 	if (!GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	    /*
@@ -1743,6 +1797,10 @@ Tcl_StackChannel(
 	statePtr->csPtrR = NULL;
 	statePtr->csPtrW = NULL;
 
+	/*
+	 * TODO: Examine what can go wrong if Tcl_Flush() call disturbs
+	 * the stacking state of this channel during its operations.
+	 */
 	if (Tcl_Flush((Tcl_Channel) prevChanPtr) != TCL_OK) {
 	    statePtr->csPtrR = csPtrR;
 	    statePtr->csPtrW = csPtrW;
@@ -1774,17 +1832,17 @@ Tcl_StackChannel(
      */
 
     if (((mask & TCL_READABLE) != 0) && (statePtr->inQueueHead != NULL)) {
+
 	/*
-	 * Remark: It is possible that the channel buffers contain data from
-	 * some earlier push-backs.
+	 * When statePtr->inQueueHead is not NULL, we know
+	 * prevChanPtr->inQueueHead must be NULL.
 	 */
 
-	statePtr->inQueueTail->nextPtr = prevChanPtr->inQueueHead;
-	prevChanPtr->inQueueHead = statePtr->inQueueHead;
+	assert(prevChanPtr->inQueueHead == NULL);
+	assert(prevChanPtr->inQueueTail == NULL);
 
-	if (prevChanPtr->inQueueTail == NULL) {
-	    prevChanPtr->inQueueTail = statePtr->inQueueTail;
-	}
+	prevChanPtr->inQueueHead = statePtr->inQueueHead;
+	prevChanPtr->inQueueTail = statePtr->inQueueTail;
 
 	statePtr->inQueueHead = NULL;
 	statePtr->inQueueTail = NULL;
@@ -1872,6 +1930,13 @@ Tcl_UnstackChannel(
 	 * into the old structure.
 	 */
 
+	/*
+	 * TODO: Figure out how to handle the situation where the chan
+	 * operations called below by this unstacking operation cause
+	 * another unstacking recursively.  In that case the downChanPtr
+	 * value we're holding on to will not be the right thing.
+	 */
+
 	Channel *downChanPtr = chanPtr->downChanPtr;
 
 	/*
@@ -1976,7 +2041,7 @@ Tcl_UnstackChannel(
 	 */
 
 	Tcl_EventuallyFree(chanPtr, TCL_DYNAMIC);
-	UpdateInterest(downChanPtr);
+	UpdateInterest(statePtr->topChanPtr);
 
 	if (result != 0) {
 	    Tcl_SetErrno(result);
@@ -2288,8 +2353,36 @@ AllocChannelBuffer(
     bufPtr->nextRemoved	= BUFFER_PADDING;
     bufPtr->bufLength	= length + BUFFER_PADDING;
     bufPtr->nextPtr	= NULL;
+    bufPtr->refCount	= 1;
     return bufPtr;
 }
+
+static void
+PreserveChannelBuffer(
+    ChannelBuffer *bufPtr)
+{
+    if (bufPtr->refCount == 0) {
+	Tcl_Panic("Reuse of ChannelBuffer! %p", bufPtr);
+    }
+    bufPtr->refCount++;
+}
+
+static void
+ReleaseChannelBuffer(
+    ChannelBuffer *bufPtr)
+{
+    if (--bufPtr->refCount) {
+	return;
+    }
+    ckfree(bufPtr);
+}
+
+static int
+IsShared(
+    ChannelBuffer *bufPtr)
+{
+    return bufPtr->refCount > 1;
+}
 
 /*
  *----------------------------------------------------------------------
@@ -2320,20 +2413,23 @@ RecycleBuffer(
     /*
      * Do we have to free the buffer to the OS?
      */
+    if (IsShared(bufPtr)) {
+	mustDiscard = 1;
+    }
 
     if (mustDiscard) {
-	ckfree(bufPtr);
+	ReleaseChannelBuffer(bufPtr);
 	return;
     }
 
     /*
-     * Only save buffers which are at least as big as the requested buffersize
-     * for the channel. This is to honor dynamic changes of the buffersize
+     * Only save buffers which have the requested buffersize for the
+     * channel. This is to honor dynamic changes of the buffersize
      * made by the user.
      */
 
-    if ((bufPtr->bufLength - BUFFER_PADDING) < statePtr->bufSize) {
-	ckfree(bufPtr);
+    if ((bufPtr->bufLength - BUFFER_PADDING) != statePtr->bufSize) {
+	ReleaseChannelBuffer(bufPtr);
 	return;
     }
 
@@ -2368,7 +2464,7 @@ RecycleBuffer(
      * If we reached this code we return the buffer to the OS.
      */
 
-    ckfree(bufPtr);
+    ReleaseChannelBuffer(bufPtr);
     return;
 
   keepBuffer:
@@ -2406,6 +2502,11 @@ DiscardOutputQueued(
     }
     statePtr->outQueueHead = NULL;
     statePtr->outQueueTail = NULL;
+    bufPtr = statePtr->curOutPtr;
+    if (bufPtr && BytesLeft(bufPtr)) {
+	statePtr->curOutPtr = NULL;
+	RecycleBuffer(statePtr, bufPtr, 0);
+    }
 }
 
 /*
@@ -2473,8 +2574,6 @@ FlushChannel(
     ChannelState *statePtr = chanPtr->state;
 				/* State of the channel stack. */
     ChannelBuffer *bufPtr;	/* Iterates over buffered output queue. */
-    int toWrite;		/* Amount of output data in current buffer
-				 * available to be written. */
     int written;		/* Amount of output data actually written in
 				 * current round. */
     int errorCode = 0;		/* Stores POSIX error codes from channel
@@ -2494,63 +2593,58 @@ FlushChannel(
     }
 
     /*
-     * Loop over the queued buffers and attempt to flush as much as possible
-     * of the queued output to the channel.
+     * Should we shift the current output buffer over to the output queue?
+     * First check that there are bytes in it.  If so then...
+     * If the output queue is empty, then yes, trusting the caller called
+     * us only when written bytes ought to be flushed.
+     * If the current output buffer is full, then yes, so we can meet
+     * the post-condition that on a successful return to caller we've
+     * left space in the current output buffer for more writing (the flush
+     * call was to make new room).
+     * Otherwise, no.  Keep the current output buffer where it is so more
+     * can be written to it, possibly filling it, to promote more efficient
+     * buffer usage.
      */
 
-    Tcl_Preserve(chanPtr);
-    while (1) {
-	/*
-	 * If the queue is empty and there is a ready current buffer, OR if
-	 * the current buffer is full, then move the current buffer to the
-	 * queue.
-	 */
-
-	if (((statePtr->curOutPtr != NULL) &&
-		IsBufferFull(statePtr->curOutPtr))
-		|| (GotFlag(statePtr, BUFFER_READY) &&
-			(statePtr->outQueueHead == NULL))) {
-	    ResetFlag(statePtr, BUFFER_READY);
-	    statePtr->curOutPtr->nextPtr = NULL;
-	    if (statePtr->outQueueHead == NULL) {
-		statePtr->outQueueHead = statePtr->curOutPtr;
-	    } else {
-		statePtr->outQueueTail->nextPtr = statePtr->curOutPtr;
-	    }
-	    statePtr->outQueueTail = statePtr->curOutPtr;
-	    statePtr->curOutPtr = NULL;
+    bufPtr = statePtr->curOutPtr;
+    if (bufPtr && BytesLeft(bufPtr) && /* Keep empties off queue */
+	    (statePtr->outQueueHead == NULL || IsBufferFull(bufPtr))) {
+	if (statePtr->outQueueHead == NULL) {
+	    statePtr->outQueueHead = bufPtr;
+	} else {
+	    statePtr->outQueueTail->nextPtr = bufPtr;
 	}
-	bufPtr = statePtr->outQueueHead;
+	statePtr->outQueueTail = bufPtr;
+	statePtr->curOutPtr = NULL;
+    }
 
-	/*
-	 * If we are not being called from an async flush and an async flush
-	 * is active, we just return without producing any output.
-	 */
+    assert(!IsBufferFull(statePtr->curOutPtr));
 
-	if (!calledFromAsyncFlush && GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
-	    errorCode = 0;
-	    goto done;
-	}
+    /*
+     * If we are not being called from an async flush and an async flush
+     * is active, we just return without producing any output.
+     */
 
-	/*
-	 * If the output queue is still empty, break out of the while loop.
-	 */
+    if (!calledFromAsyncFlush && GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
+	return 0;
+    }
 
-	if (bufPtr == NULL) {
-	    break;		/* Out of the "while (1)". */
-	}
+    /*
+     * Loop over the queued buffers and attempt to flush as much as possible
+     * of the queued output to the channel.
+     */
+
+    Tcl_Preserve(chanPtr);
+    while (statePtr->outQueueHead) {
+	bufPtr = statePtr->outQueueHead;
 
 	/*
 	 * Produce the output on the channel.
 	 */
 
-	toWrite = BytesLeft(bufPtr);
-	if (toWrite == 0) {
-            written = 0;
-	} else {
-	    written = ChanWrite(chanPtr, RemovePoint(bufPtr), toWrite,
-		    &errorCode);
-	}
+	PreserveChannelBuffer(bufPtr);
+	written = ChanWrite(chanPtr, RemovePoint(bufPtr), BytesLeft(bufPtr),
+		&errorCode);
 
 	/*
 	 * If the write failed completely attempt to start the asynchronous
@@ -2565,6 +2659,7 @@ FlushChannel(
 
 	    if (errorCode == EINTR) {
 		errorCode = 0;
+		ReleaseChannelBuffer(bufPtr);
 		continue;
 	    }
 
@@ -2586,6 +2681,7 @@ FlushChannel(
 		    UpdateInterest(chanPtr);
 		}
 		errorCode = 0;
+		ReleaseChannelBuffer(bufPtr);
 		break;
 	    }
 
@@ -2647,14 +2743,15 @@ FlushChannel(
 	     */
 
 	    DiscardOutputQueued(statePtr);
-	    continue;
+	    ReleaseChannelBuffer(bufPtr);
+	    break;
 	} else {
+	    /* TODO: Consider detecting and reacting to short writes
+	     * on blocking channels.  Ought not happen.  See iocmd-24.2. */
 	    wroteSome = 1;
 	}
 
-	if (!IsBufferEmpty(bufPtr)) {
-	    bufPtr->nextRemoved += written;
-	}
+	bufPtr->nextRemoved += written;
 
 	/*
 	 * If this buffer is now empty, recycle it.
@@ -2667,7 +2764,8 @@ FlushChannel(
 	    }
 	    RecycleBuffer(statePtr, bufPtr, 0);
 	}
-    }	/* Closes "while (1)". */
+	ReleaseChannelBuffer(bufPtr);
+    }	/* Closes "while". */
 
     /*
      * If we wrote some data while flushing in the background, we are done.
@@ -2682,6 +2780,19 @@ FlushChannel(
 	} else if (statePtr->outQueueHead == NULL) {
 	    ResetFlag(statePtr, BG_FLUSH_SCHEDULED);
 	    ChanWatch(chanPtr, statePtr->interestMask);
+	} else {
+
+	    /*
+	     * When we are calledFromAsyncFlush, that means a writable
+	     * state on the channel triggered the call, so we should be
+	     * able to write something.  Either we did write something 
+	     * and wroteSome should be set, or there was nothing left to
+	     * write in this call, and we've completed the BG flush.
+	     * These are the two cases above.  If we get here, that means
+	     * there is some kind failure in the writable event machinery.
+	     */
+
+	    assert(!calledFromAsyncFlush);
 	}
     }
 
@@ -2768,7 +2879,7 @@ CloseChannel(
      */
 
     if (statePtr->curOutPtr != NULL) {
-	ckfree(statePtr->curOutPtr);
+	ReleaseChannelBuffer(statePtr->curOutPtr);
 	statePtr->curOutPtr = NULL;
     }
 
@@ -3180,10 +3291,18 @@ Tcl_Close(
 
     stickyError = 0;
 
-    if ((statePtr->encoding != NULL) && (statePtr->curOutPtr != NULL)
-	    && (CheckChannelErrors(statePtr, TCL_WRITABLE) == 0)) {
-	statePtr->outputEncodingFlags |= TCL_ENCODING_END;
-	if (WriteChars(chanPtr, "", 0) < 0) {
+    if (GotFlag(statePtr, TCL_WRITABLE) && (statePtr->encoding != NULL)
+	    && !(statePtr->outputEncodingFlags & TCL_ENCODING_START)) {
+
+	int code = CheckChannelErrors(statePtr, TCL_WRITABLE);
+
+	if (code == 0) {
+	    statePtr->outputEncodingFlags |= TCL_ENCODING_END;
+	    code = WriteChars(chanPtr, "", 0);
+	    statePtr->outputEncodingFlags &= ~TCL_ENCODING_END;
+	    statePtr->outputEncodingFlags |= TCL_ENCODING_START;
+	}
+	if (code < 0) {
 	    stickyError = Tcl_GetErrno();
 	}
 
@@ -3218,14 +3337,6 @@ Tcl_Close(
     ResetFlag(statePtr, CHANNEL_INCLOSE);
 
     /*
-     * Ensure that the last output buffer will be flushed.
-     */
-
-    if ((statePtr->curOutPtr != NULL) && IsBufferReady(statePtr->curOutPtr)) {
-	SetFlag(statePtr, BUFFER_READY);
-    }
-
-    /*
      * If this channel supports it, close the read side, since we don't need
      * it anymore and this will help avoid deadlocks on some channel types.
      */
@@ -3270,7 +3381,17 @@ Tcl_Close(
 	    Tcl_SetObjResult(interp,
 			     Tcl_NewStringObj(Tcl_PosixError(interp), -1));
 	}
-	flushcode = -1;
+	return TCL_ERROR;
+    }
+    /*
+     * Bug 97069ea11a: set error message if a flush code is set and no error
+     * message set up to now.
+     */
+    if (flushcode != 0 && interp != NULL
+	    && 0 == Tcl_GetCharLength(Tcl_GetObjResult(interp)) ) {
+	Tcl_SetErrno(flushcode);
+	Tcl_SetObjResult(interp,
+		Tcl_NewStringObj(Tcl_PosixError(interp), -1));
     }
     if ((flushcode != 0) || (result != 0)) {
 	return TCL_ERROR;
@@ -3383,10 +3504,6 @@ Tcl_CloseEx(
 
 	return CloseChannelPart(interp, chanPtr, 0, flags);
     } else if (flags & TCL_CLOSE_WRITE) {
-	if ((statePtr->curOutPtr != NULL) &&
-		IsBufferReady(statePtr->curOutPtr)) {
-	    SetFlag(statePtr, BUFFER_READY);
-	}
 	Tcl_Preserve(statePtr);
 	if (!GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	    /*
@@ -3448,14 +3565,6 @@ CloseWrite(
     int result = 0;
 
     /*
-     * Ensure that the last output buffer will be flushed.
-     */
-
-    if ((statePtr->curOutPtr != NULL) && IsBufferReady(statePtr->curOutPtr)) {
-	SetFlag(statePtr, BUFFER_READY);
-    }
-
-    /*
      * The call to FlushChannel will flush any queued output and invoke the
      * close function of the channel driver, or it will set up the channel to
      * be flushed and closed asynchronously.
@@ -3967,12 +4076,25 @@ static int
 WillRead(
     Channel *chanPtr)
 {
+    if (chanPtr->typePtr == NULL) {
+	/* Prevent read attempts on a closed channel */
+        DiscardInputQueued(chanPtr->state, 0);
+	Tcl_SetErrno(EINVAL);
+	return -1;
+    }
     if ((chanPtr->typePtr->seekProc != NULL)
             && (Tcl_OutputBuffered((Tcl_Channel) chanPtr) > 0)) {
-        if ((chanPtr->state->curOutPtr != NULL)
-                && IsBufferReady(chanPtr->state->curOutPtr)) {
-            SetFlag(chanPtr->state, BUFFER_READY);
-        }
+
+	/*
+	 * CAVEAT - The assumption here is that FlushChannel() will
+	 * push out the bytes of any writes that are in progress.
+	 * Since this is a seekable channel, we assume it is not one
+	 * that can block and force bg flushing.  Channels we know that
+	 * can do that -- sockets, pipes -- are not seekable.  If the
+	 * assumption is wrong, more drastic measures may be required here
+	 * like temporarily setting the channel into blocking mode.
+	 */
+
         if (FlushChannel(NULL, chanPtr, 0) != 0) {
             return -1;
         }
@@ -4053,6 +4175,7 @@ Write(
 	    bufPtr->nextAdded += saved;
 	    saved = 0;
 	}
+	PreserveChannelBuffer(bufPtr);
 	dst = InsertPoint(bufPtr);
 	dstLen = SpaceLeft(bufPtr);
 
@@ -4066,6 +4189,7 @@ Write(
 	
 	if ((result != TCL_OK) && (srcRead + dstWrote == 0)) {
 	    /* We're reading from invalid/incomplete UTF-8 */
+	    ReleaseChannelBuffer(bufPtr);
 	    if (total == 0) {
 		Tcl_SetErrno(EINVAL);
 		return -1;
@@ -4108,9 +4232,7 @@ Write(
 		&statePtr->outputEncodingState, dst,
 		dstLen + BUFFER_PADDING, &srcRead, &dstWrote, NULL);
 
-	    if (srcRead != nlLen) {
-		Tcl_Panic("Can This Happen?");
-	    }
+	    assert (srcRead == nlLen);
 
 	    bufPtr->nextAdded += dstWrote;
 	    src++;
@@ -4142,6 +4264,7 @@ Write(
 
 	if (IsBufferFull(bufPtr)) {
 	    if (FlushChannel(NULL, chanPtr, 0) != 0) {
+		ReleaseChannelBuffer(bufPtr);
 		return -1;
 	    }
 	    flushed += statePtr->bufSize;
@@ -4149,10 +4272,10 @@ Write(
 		needNlFlush = 0;
 	    }
 	}
+	ReleaseChannelBuffer(bufPtr);
     }
     if ((flushed < total) && (GotFlag(statePtr, CHANNEL_UNBUFFERED) ||
 	    (needNlFlush && GotFlag(statePtr, CHANNEL_LINEBUFFERED)))) {
-	SetFlag(statePtr, BUFFER_READY);
 	if (FlushChannel(NULL, chanPtr, 0) != 0) {
 	    return -1;
 	}
@@ -4240,8 +4363,7 @@ Tcl_GetsObj(
     Tcl_EncodingState oldState;
 
     if (CheckChannelErrors(statePtr, TCL_READABLE) != 0) {
-	copiedTotal = -1;
-	goto done;
+	return -1;
     }
 
     /*
@@ -4261,6 +4383,7 @@ Tcl_GetsObj(
      */
 
     chanPtr = statePtr->topChanPtr;
+    Tcl_Preserve(chanPtr);
 
     bufPtr = statePtr->inQueueHead;
     encoding = statePtr->encoding;
@@ -4473,6 +4596,7 @@ Tcl_GetsObj(
 		Tcl_SetObjLength(objPtr, oldLength);
 		CommonGetsCleanup(chanPtr);
 		copiedTotal = -1;
+		ResetFlag(statePtr, CHANNEL_BLOCKED);
 		goto done;
 	    }
 	    goto gotEOL;
@@ -4494,7 +4618,11 @@ Tcl_GetsObj(
      * self-modifying reflected transforms.
      */
 
-    chanPtr = statePtr->topChanPtr;
+    if (chanPtr != statePtr->topChanPtr) {
+	Tcl_Release(chanPtr);
+	chanPtr = statePtr->topChanPtr;
+	Tcl_Preserve(chanPtr);
+    }
 
     bufPtr = gs.bufPtr;
     if (bufPtr == NULL) {
@@ -4528,16 +4656,18 @@ Tcl_GetsObj(
      * Regenerate the top channel, in case it was changed due to
      * self-modifying reflected transforms.
      */
-
-    chanPtr = statePtr->topChanPtr;
-
+    if (chanPtr != statePtr->topChanPtr) {
+	Tcl_Release(chanPtr);
+	chanPtr = statePtr->topChanPtr;
+	Tcl_Preserve(chanPtr);
+    }
     bufPtr = statePtr->inQueueHead;
-    if (bufPtr == NULL) {
-	Tcl_Panic("Tcl_GetsObj: restore reached with bufPtr==NULL");
+    if (bufPtr != NULL) {
+	bufPtr->nextRemoved = oldRemoved;
+	bufPtr = bufPtr->nextPtr;
     }
-    bufPtr->nextRemoved = oldRemoved;
 
-    for (bufPtr = bufPtr->nextPtr; bufPtr != NULL; bufPtr = bufPtr->nextPtr) {
+    for ( ; bufPtr != NULL; bufPtr = bufPtr->nextPtr) {
 	bufPtr->nextRemoved = BUFFER_PADDING;
     }
     CommonGetsCleanup(chanPtr);
@@ -4570,10 +4700,13 @@ Tcl_GetsObj(
      * Regenerate the top channel, in case it was changed due to
      * self-modifying reflected transforms.
      */
-
-    chanPtr = statePtr->topChanPtr;
-
+    if (chanPtr != statePtr->topChanPtr) {
+	Tcl_Release(chanPtr);
+	chanPtr = statePtr->topChanPtr;
+	Tcl_Preserve(chanPtr);
+    }
     UpdateInterest(chanPtr);
+    Tcl_Release(chanPtr);
     return copiedTotal;
 }
 
@@ -4619,6 +4752,7 @@ TclGetsObjBinary(
      */
 
     chanPtr = statePtr->topChanPtr;
+    Tcl_Preserve(chanPtr);
 
     bufPtr = statePtr->inQueueHead;
 
@@ -4666,16 +4800,17 @@ TclGetsObjBinary(
 	     * device. Side effect is to allocate another channel buffer.
 	     */
 
-	    if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
-		if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
-		    goto restore;
-		}
-		ResetFlag(statePtr, CHANNEL_BLOCKED);
+	    if (GotFlag(statePtr, CHANNEL_BLOCKED|CHANNEL_NONBLOCKING)
+		    == (CHANNEL_BLOCKED|CHANNEL_NONBLOCKING)) {
+		goto restore;
 	    }
 	    if (GetInput(chanPtr) != 0) {
 		goto restore;
 	    }
 	    bufPtr = statePtr->inQueueTail;
+	    if (bufPtr == NULL) {
+		goto restore;
+	    }
 	}
 
 	dst = (unsigned char *) RemovePoint(bufPtr);
@@ -4730,6 +4865,7 @@ TclGetsObjBinary(
 		byteArray = Tcl_SetByteArrayLength(objPtr, oldLength);
 		CommonGetsCleanup(chanPtr);
 		copiedTotal = -1;
+		ResetFlag(statePtr, CHANNEL_BLOCKED);
 		goto done;
 	    }
 	    goto gotEOL;
@@ -4788,12 +4924,12 @@ TclGetsObjBinary(
 
   restore:
     bufPtr = statePtr->inQueueHead;
-    if (bufPtr == NULL) {
-	Tcl_Panic("TclGetsObjBinary: restore reached with bufPtr==NULL");
+    if (bufPtr) {
+	bufPtr->nextRemoved = oldRemoved;
+	bufPtr = bufPtr->nextPtr;
     }
-    bufPtr->nextRemoved = oldRemoved;
 
-    for (bufPtr = bufPtr->nextPtr; bufPtr != NULL; bufPtr = bufPtr->nextPtr) {
+    for ( ; bufPtr != NULL; bufPtr = bufPtr->nextPtr) {
 	bufPtr->nextRemoved = BUFFER_PADDING;
     }
     CommonGetsCleanup(chanPtr);
@@ -4822,6 +4958,7 @@ TclGetsObjBinary(
 
   done:
     UpdateInterest(chanPtr);
+    Tcl_Release(chanPtr);
     return copiedTotal;
 }
 
@@ -4898,7 +5035,7 @@ FilterInputBytes(
     ChannelState *statePtr = chanPtr->state;
 				/* State info for channel */
     ChannelBuffer *bufPtr;
-    char *raw, *rawStart, *dst;
+    char *raw, *dst;
     int offset, toRead, dstNeeded, spaceLeft, result, rawLen;
     Tcl_Obj *objPtr;
 #define ENCODING_LINESIZE 20	/* Lower bound on how many bytes to convert at
@@ -4932,14 +5069,6 @@ FilterInputBytes(
 	 */
 
     read:
-	if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
-	    if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
-		gsPtr->charsWrote = 0;
-		gsPtr->rawRead = 0;
-		return -1;
-	    }
-	    ResetFlag(statePtr, CHANNEL_BLOCKED);
-	}
 	if (GetInput(chanPtr) != 0) {
 	    gsPtr->charsWrote = 0;
 	    gsPtr->rawRead = 0;
@@ -4947,6 +5076,11 @@ FilterInputBytes(
 	}
 	bufPtr = statePtr->inQueueTail;
 	gsPtr->bufPtr = bufPtr;
+	if (bufPtr == NULL) {
+	    gsPtr->charsWrote = 0;
+	    gsPtr->rawRead = 0;
+	    return -1;
+	}
     }
 
     /*
@@ -4955,8 +5089,7 @@ FilterInputBytes(
      * string rep if we need more space.
      */
 
-    rawStart = RemovePoint(bufPtr);
-    raw = rawStart;
+    raw = RemovePoint(bufPtr);
     rawLen = BytesLeft(bufPtr);
 
     dst = *gsPtr->dstPtr;
@@ -5023,9 +5156,15 @@ FilterInputBytes(
 	    } else {
 		/*
 		 * There are no more cached raw bytes left. See if we can get
-		 * some more.
+		 * some more, but avoid blocking on a non-blocking channel.
 		 */
 
+		if (GotFlag(statePtr, CHANNEL_NONBLOCKING|CHANNEL_BLOCKED)
+			== (CHANNEL_NONBLOCKING|CHANNEL_BLOCKED)) {
+		    gsPtr->charsWrote = 0;
+		    gsPtr->rawRead = 0;
+		    return -1;
+		}
 		goto read;
 	    }
 	} else {
@@ -5264,134 +5403,77 @@ Tcl_Read(
 int
 Tcl_ReadRaw(
     Tcl_Channel chan,		/* The channel from which to read. */
-    char *bufPtr,		/* Where to store input read. */
+    char *readBuf,		/* Where to store input read. */
     int bytesToRead)		/* Maximum number of bytes to read. */
 {
     Channel *chanPtr = (Channel *) chan;
     ChannelState *statePtr = chanPtr->state;
 				/* State info for channel */
-    int nread, result, copied, copiedNow;
-
-    /*
-     * The check below does too much because it will reject a call to this
-     * function with a channel which is part of an 'fcopy'. But we have to
-     * allow this here or else the chaining in the transformation drivers will
-     * fail with 'file busy' error instead of retrieving and transforming the
-     * data to copy.
-     *
-     * We let the check procedure now believe that there is no fcopy in
-     * progress. A better solution than this might be an additional flag
-     * argument to switch off specific checks.
-     */
+    int copied = 0;
 
     if (CheckChannelErrors(statePtr, TCL_READABLE | CHANNEL_RAW_MODE) != 0) {
 	return -1;
     }
 
-    /*
-     * Check for information in the push-back buffers. If there is some, use
-     * it. Go to the driver only if there is none (anymore) and the caller
-     * requests more bytes.
-     */
+    /* First read bytes from the push-back buffers. */
 
-    for (copied = 0; copied < bytesToRead; copied += copiedNow) {
-	copiedNow = CopyBuffer(chanPtr, bufPtr + copied,
-		bytesToRead - copied);
-	if (copiedNow == 0) {
-	    if (GotFlag(statePtr, CHANNEL_EOF)) {
-		goto done;
-	    }
-	    if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
-		if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
-		    goto done;
-		}
-		ResetFlag(statePtr, CHANNEL_BLOCKED);
-	    }
+    while (chanPtr->inQueueHead && bytesToRead > 0) {
+	ChannelBuffer *bufPtr = chanPtr->inQueueHead;
+	int bytesInBuffer = BytesLeft(bufPtr);
+	int toCopy = (bytesInBuffer < bytesToRead) ? bytesInBuffer
+		: bytesToRead;
 
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-	    /*
-	     * [Bug 943274]. Better emulation of non-blocking channels for
-	     * channels without BlockModeProc, by keeping track of true
-	     * fileevents generated by the OS == Data waiting and reading if
-	     * and only if we are sure to have data.
-	     */
+	/* Copy the current chunk into the read buffer. */
 
-	    if (GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
-		    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
-		    !GotFlag(statePtr, CHANNEL_HAS_MORE_DATA)) {
-		/*
-		 * We bypass the driver; it would block as no data is
-		 * available.
-		 */
+	memcpy(readBuf, RemovePoint(bufPtr), (size_t) toCopy);
+	bufPtr->nextRemoved += toCopy;
+	copied += toCopy;
+	readBuf += toCopy;
+	bytesToRead -= toCopy;
 
-		nread = -1;
-		result = EWOULDBLOCK;
-	    } else
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-	    {
-		/*
-		 * Now go to the driver to get as much as is possible to fill
-		 * the remaining request. Do all the error handling by
-		 * ourselves. The code was stolen from 'GetInput' and slightly
-		 * adapted (different return value here).
-		 *
-		 * The case of 'bytesToRead == 0' at this point cannot happen.
-		 */
+	/* If the current buffer is empty recycle it. */
 
-		nread = ChanRead(chanPtr, bufPtr + copied,
-			bytesToRead - copied, &result);
+	if (IsBufferEmpty(bufPtr)) {
+	    chanPtr->inQueueHead = bufPtr->nextPtr;
+	    if (chanPtr->inQueueHead == NULL) {
+		chanPtr->inQueueTail = NULL;
 	    }
+	    RecycleBuffer(chanPtr->state, bufPtr, 0);
+	}
+    }
 
-	    if (nread > 0) {
-		/*
-		 * If we get a short read, signal up that we may be BLOCKED.
-		 * We should avoid calling the driver because on some
-		 * platforms we will block in the low level reading code even
-		 * though the channel is set into nonblocking mode.
-		 */
+    /* Go to the driver if more data needed. */
 
-		if (nread < (bytesToRead - copied)) {
-		    SetFlag(statePtr, CHANNEL_BLOCKED);
-		}
+    if (bytesToRead > 0) {
 
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-		if (nread <= (bytesToRead - copied)) {
-		    /*
-		     * [Bug 943274] We have read the available data, clear
-		     * flag.
-		     */
-
-		    ResetFlag(statePtr, CHANNEL_HAS_MORE_DATA);
-		}
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-	    } else if (nread == 0) {
-		SetFlag(statePtr, CHANNEL_EOF);
-		statePtr->inputEncodingFlags |= TCL_ENCODING_END;
-
-	    } else if (nread < 0) {
-		if ((result == EWOULDBLOCK) || (result == EAGAIN)) {
-		    if (copied > 0) {
-			/*
-			 * Information that was copied earlier has precedence
-			 * over EAGAIN/WOULDBLOCK handling.
-			 */
-
-			return copied;
-		    }
+	int nread = ChanRead(chanPtr, readBuf+copied, bytesToRead);
 
-		    SetFlag(statePtr, CHANNEL_BLOCKED);
-		    result = EAGAIN;
-		}
-
-		Tcl_SetErrno(result);
-		return -1;
+	if (nread > 0) {
+	    /* Successful read (short is OK) - add to bytes copied */
+	    copied += nread;
+	} else if (nread < 0) {
+	    /*
+	     * An error signaled.  If CHANNEL_BLOCKED, then the error
+	     * is not real, but an indication of blocked state.  In
+	     * that case, retain the flag and let caller receive the
+	     * short read of copied bytes from the pushback.
+	     * HOWEVER, if copied==0 bytes from pushback then repeat
+	     * signalling the blocked state as an error to caller so
+	     * there is no false report of an EOF.
+	     * When !CHANNEL_BLOCKED, the error is real and passes on
+	     * to caller.
+	     */
+	    if (!GotFlag(statePtr, CHANNEL_BLOCKED) || copied == 0) {
+		copied = -1;
 	    }
-
-	    return copied + nread;
+	} else if (copied > 0) {
+	    /*
+	     * nread == 0.  Driver is at EOF, but if copied>0 bytes
+	     * from pushback, then we should not signal it yet.
+	     */
+	    ResetFlag(statePtr, CHANNEL_EOF);
 	}
     }
-
-  done:
     return copied;
 }
 
@@ -5488,8 +5570,9 @@ DoReadChars(
     ChannelState *statePtr = chanPtr->state;
 				/* State info for channel */
     ChannelBuffer *bufPtr;
-    int offset, factor, copied, copiedNow, result;
+    int factor, copied, copiedNow, result;
     Tcl_Encoding encoding;
+    int binaryMode;
 #define UTF_EXPANSION_FACTOR	1024
 
     /*
@@ -5499,9 +5582,14 @@ DoReadChars(
     chanPtr = statePtr->topChanPtr;
     encoding = statePtr->encoding;
     factor = UTF_EXPANSION_FACTOR;
+    Tcl_Preserve(chanPtr);
+
+    binaryMode = (encoding == NULL)
+	    && (statePtr->inputTranslation == TCL_TRANSLATE_LF) 
+	    && (statePtr->inEofChar == '\0');
 
     if (appendFlag == 0) {
-	if (encoding == NULL) {
+	if (binaryMode) {
 	    Tcl_SetByteArrayLength(objPtr, 0);
 	} else {
 	    Tcl_SetObjLength(objPtr, 0);
@@ -5510,27 +5598,23 @@ DoReadChars(
 	     * We're going to access objPtr->bytes directly, so we must ensure
 	     * that this is actually a string object (otherwise it might have
 	     * been pure Unicode).
+	     *
+	     * Probably not needed anymore.
 	     */
 
 	    TclGetString(objPtr);
 	}
-	offset = 0;
-    } else {
-	if (encoding == NULL) {
-	    Tcl_GetByteArrayFromObj(objPtr, &offset);
-	} else {
-	    TclGetStringFromObj(objPtr, &offset);
-	}
     }
 
+    /* Must clear the BLOCKED flag here since we check before reading */
+    ResetFlag(statePtr, CHANNEL_BLOCKED);
     for (copied = 0; (unsigned) toRead > 0; ) {
 	copiedNow = -1;
 	if (statePtr->inQueueHead != NULL) {
-	    if (encoding == NULL) {
-		copiedNow = ReadBytes(statePtr, objPtr, toRead, &offset);
+	    if (binaryMode) {
+		copiedNow = ReadBytes(statePtr, objPtr, toRead);
 	    } else {
-		copiedNow = ReadChars(statePtr, objPtr, toRead, &offset,
-			&factor);
+		copiedNow = ReadChars(statePtr, objPtr, toRead, &factor);
 	    }
 
 	    /*
@@ -5553,19 +5637,21 @@ DoReadChars(
 	    if (GotFlag(statePtr, CHANNEL_EOF)) {
 		break;
 	    }
-	    if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
-		if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
-		    break;
-		}
-		ResetFlag(statePtr, CHANNEL_BLOCKED);
+	    if (GotFlag(statePtr, CHANNEL_NONBLOCKING|CHANNEL_BLOCKED)
+		    == (CHANNEL_NONBLOCKING|CHANNEL_BLOCKED)) {
+		break;
 	    }
 	    result = GetInput(chanPtr);
+	    if (chanPtr != statePtr->topChanPtr) {
+		Tcl_Release(chanPtr);
+		chanPtr = statePtr->topChanPtr;
+		Tcl_Preserve(chanPtr);
+	    }
 	    if (result != 0) {
-		if (result == EAGAIN) {
-		    break;
+		if (!GotFlag(statePtr, CHANNEL_BLOCKED)) {
+		    copied = -1;
 		}
-		copied = -1;
-		goto done;
+		break;
 	    }
 	} else {
 	    copied += copiedNow;
@@ -5573,27 +5659,31 @@ DoReadChars(
 	}
     }
 
-    ResetFlag(statePtr, CHANNEL_BLOCKED);
-    if (encoding == NULL) {
-	Tcl_SetByteArrayLength(objPtr, offset);
-    } else {
-	Tcl_SetObjLength(objPtr, offset);
-    }
-
     /*
-     * Update the notifier state so we don't block while there is still data
-     * in the buffers.
+     * Failure to fill a channel buffer may have left channel reporting
+     * a "blocked" state, but so long as we fulfilled the request here,
+     * the caller does not consider us blocked.
      */
+    if (toRead == 0) {
+	ResetFlag(statePtr, CHANNEL_BLOCKED);
+    }
 
-  done:
     /*
      * Regenerate the top channel, in case it was changed due to
      * self-modifying reflected transforms.
      */
+    if (chanPtr != statePtr->topChanPtr) {
+	Tcl_Release(chanPtr);
+	chanPtr = statePtr->topChanPtr;
+	Tcl_Preserve(chanPtr);
+    }
 
-    chanPtr = statePtr->topChanPtr;
-
+    /*
+     * Update the notifier state so we don't block while there is still data
+     * in the buffers.
+     */
     UpdateInterest(chanPtr);
+    Tcl_Release(chanPtr);
     return copied;
 }
 
@@ -5611,13 +5701,11 @@ DoReadChars(
  *	allocated to hold data read from the channel as needed.
  *
  * Results:
- *	The return value is the number of bytes appended to the object and
- *	*offsetPtr is filled with the total number of bytes in the object
- *	(greater than the return value if there were already bytes in the
- *	object).
+ *	The return value is the number of bytes appended to the object, or
+ *	-1 to indicate that zero bytes were read due to an EOF.
  *
  * Side effects:
- *	None.
+ *	The storage of bytes in objPtr can cause (re-)allocation of memory.
  *
  *---------------------------------------------------------------------------
  */
@@ -5630,72 +5718,22 @@ ReadBytes(
 				 * been allocated to hold data, not how many
 				 * bytes of data have been stored in the
 				 * object. */
-    int bytesToRead,		/* Maximum number of bytes to store, or < 0 to
+    int bytesToRead)		/* Maximum number of bytes to store, or < 0 to
 				 * get all available bytes. Bytes are obtained
 				 * from the first buffer in the queue - even
 				 * if this number is larger than the number of
 				 * bytes available in the first buffer, only
 				 * the bytes from the first buffer are
 				 * returned. */
-    int *offsetPtr)		/* On input, contains how many bytes of objPtr
-				 * have been used to hold data. On output,
-				 * filled with how many bytes are now being
-				 * used. */
 {
-    int toRead, srcLen, offset, length, srcRead, dstWrote;
-    ChannelBuffer *bufPtr;
-    char *src, *dst;
-
-    offset = *offsetPtr;
-
-    bufPtr = statePtr->inQueueHead;
-    src = RemovePoint(bufPtr);
-    srcLen = BytesLeft(bufPtr);
-
-    toRead = bytesToRead;
-    if ((unsigned) toRead > (unsigned) srcLen) {
-	toRead = srcLen;
-    }
-
-    dst = (char *) Tcl_GetByteArrayFromObj(objPtr, &length);
-    if (toRead > length - offset - 1) {
-	/*
-	 * Double the existing size of the object or make enough room to hold
-	 * all the characters we may get from the source buffer, whichever is
-	 * larger.
-	 */
+    ChannelBuffer *bufPtr = statePtr->inQueueHead;
+    int srcLen = BytesLeft(bufPtr);
+    int toRead = bytesToRead>srcLen || bytesToRead<0 ? srcLen : bytesToRead;
 
-	length = offset * 2;
-	if (offset < toRead) {
-	    length = offset + toRead + 1;
-	}
-	dst = (char *) Tcl_SetByteArrayLength(objPtr, length);
-    }
-    dst += offset;
-
-    if (GotFlag(statePtr, INPUT_NEED_NL)) {
-	ResetFlag(statePtr, INPUT_NEED_NL);
-	if ((srcLen == 0) || (*src != '\n')) {
-	    *dst = '\r';
-	    *offsetPtr += 1;
-	    return 1;
-	}
-	*dst++ = '\n';
-	src++;
-	srcLen--;
-	toRead--;
-    }
-
-    srcRead = srcLen;
-    dstWrote = toRead;
-    if (TranslateInputEOL(statePtr, dst, src, &dstWrote, &srcRead) != 0) {
-	if (dstWrote == 0) {
-	    return -1;
-	}
-    }
-    bufPtr->nextRemoved += srcRead;
-    *offsetPtr += dstWrote;
-    return dstWrote;
+    TclAppendBytesToByteArray(objPtr, (unsigned char *) RemovePoint(bufPtr),
+	    toRead);
+    bufPtr->nextRemoved += toRead;
+    return toRead;
 }
 
 /*
@@ -5739,262 +5777,351 @@ ReadChars(
 				 * is larger than the number of characters
 				 * available in the first buffer, only the
 				 * characters from the first buffer are
-				 * returned. */
-    int *offsetPtr,		/* On input, contains how many bytes of objPtr
-				 * have been used to hold data. On output,
-				 * filled with how many bytes are now being
-				 * used. */
+				 * returned. The execption is when there is
+				 * not any complete character in the first
+				 * buffer.  In that case, a recursive call
+				 * effectively obtains chars from the
+				 * second buffer. */
     int *factorPtr)		/* On input, contains a guess of how many
 				 * bytes need to be allocated to hold the
 				 * result of converting N source bytes to
 				 * UTF-8. On output, contains another guess
 				 * based on the data seen so far. */
 {
-    int toRead, factor, offset, spaceLeft, srcLen, dstNeeded;
-    int srcRead, dstWrote, numChars, dstRead;
-    ChannelBuffer *bufPtr;
-    char *src, *dst;
-    Tcl_EncodingState oldState;
-    int encEndFlagSuppressed = 0;
+    Tcl_Encoding encoding = statePtr->encoding? statePtr->encoding
+	    : GetBinaryEncoding();
+    Tcl_EncodingState savedState = statePtr->inputEncodingState;
+    ChannelBuffer *bufPtr = statePtr->inQueueHead;
+    int savedIEFlags = statePtr->inputEncodingFlags;
+    int savedFlags = statePtr->flags;
+    char *dst, *src = RemovePoint(bufPtr);
+    int dstLimit, numBytes, srcLen = BytesLeft(bufPtr);
 
-    factor = *factorPtr;
-    offset = *offsetPtr;
-
-    bufPtr = statePtr->inQueueHead;
-    src = RemovePoint(bufPtr);
-    srcLen = BytesLeft(bufPtr);
+    /*
+     * One src byte can yield at most one character.  So when the
+     * number of src bytes we plan to read is less than the limit on
+     * character count to be read, clearly we will remain within that
+     * limit, and we can use the value of "srcLen" as a tighter limit
+     * for sizing receiving buffers.
+     */
 
-    toRead = charsToRead;
-    if ((unsigned) toRead > (unsigned) srcLen) {
-	toRead = srcLen;
-    }
+    int toRead = ((charsToRead<0)||(charsToRead > srcLen)) ? srcLen : charsToRead;
 
     /*
      * 'factor' is how much we guess that the bytes in the source buffer will
      * expand when converted to UTF-8 chars. This guess comes from analyzing
      * how many characters were produced by the previous pass.
      */
+    
+    int factor = *factorPtr;
+    int dstNeeded = TCL_UTF_MAX - 1 + toRead * factor / UTF_EXPANSION_FACTOR;
 
-    dstNeeded = TCL_UTF_MAX - 1 + toRead * factor / UTF_EXPANSION_FACTOR;
-    spaceLeft = objPtr->length - offset;
-
-    if (dstNeeded > spaceLeft) {
-	/*
-	 * Double the existing size of the object or make enough room to hold
-	 * all the characters we want from the source buffer, whichever is
-	 * larger.
-	 */
-
-	int length = offset + ((offset < dstNeeded) ? dstNeeded : offset);
-
-	if (Tcl_AttemptSetObjLength(objPtr, length) == 0) {
-	    length = offset + dstNeeded;
-	    if (Tcl_AttemptSetObjLength(objPtr, length) == 0) {
-		dstNeeded = TCL_UTF_MAX - 1 + toRead;
-		length = offset + dstNeeded;
-		Tcl_SetObjLength(objPtr, length);
-	    }
-	}
-	spaceLeft = length - offset;
-    }
+    (void) TclGetStringFromObj(objPtr, &numBytes);
+    Tcl_AppendToObj(objPtr, NULL, dstNeeded);
     if (toRead == srcLen) {
-	/*
-	 * Want to convert the whole buffer in one pass. If we have enough
-	 * space, convert it using all available space in object rather than
-	 * using the factor.
-	 */
-
-	dstNeeded = spaceLeft;
+	unsigned int size;
+	dst = TclGetStringStorage(objPtr, &size) + numBytes;
+	dstNeeded = size - numBytes;
+    } else {
+	dst = TclGetString(objPtr) + numBytes;
     }
-    dst = objPtr->bytes + offset;
 
     /*
-     * [Bug 1462248]: The cause of the crash reported in this bug is this:
-     *
-     * - ReadChars, called with a single buffer, with a incomplete
-     *	 multi-byte character at the end (only the first byte of it).
-     * - Encoding translation fails, asks for more data
-     * - Data is read, and eof is reached, TCL_ENCODING_END (TEE) is set.
-     * - ReadChar is called again, converts the first buffer, but due to TEE
-     *	 it does not check for incomplete multi-byte data, and the character
-     *	 just after the end of the first buffer is a valid completion of the
-     *	 multi-byte header in the actual buffer. The conversion reads more
-     *	 characters from the buffer then present. This causes nextRemoved to
-     *	 overshoot nextAdded and the next reads compute a negative srcLen,
-     *	 cause further translations to fail, causing copying of data into the
-     *	 next buffer using bad arguments, causing the mecpy for to eventually
-     *	 fail.
+     * This routine is burdened with satisfying several constraints.
+     * It cannot append more than 'charsToRead` chars onto objPtr.
+     * This is measured after encoding and translation transformations
+     * are completed.  There is no precise number of src bytes that can
+     * be associated with the limit.  Yet, when we are done, we must know
+     * precisely the number of src bytes that were consumed to produce
+     * the appended chars, so that all subsequent bytes are left in
+     * the buffers for future read operations.
      *
-     * In the end it is a memory access bug spiraling out of control if the
-     * conditions are _just so_. And ultimate cause is that TEE is given to a
-     * conversion where it should not. TEE signals that this is the last
-     * buffer. Except in our case it is not.
-     *
-     * My solution is to suppress TEE if the first buffer is not the last. We
-     * will eventually need it given that EOF has been reached, but not right
-     * now. This is what the new flag "endEncSuppressFlag" is for.
-     *
-     * The bug in 'Tcl_Utf2UtfProc' where it read from memory behind the
-     * actual buffer has been fixed as well, and fixes the problem with the
-     * crash too, but this would still allow the generic layer to
-     * accidentially break a multi-byte sequence if the conditions are just
-     * right, because again the ExternalToUtf would be successful where it
-     * should not.
+     * The consequence is that we have no choice but to implement a
+     * "trial and error" approach, where in general we may need to
+     * perform transformations and copies multiple times to achieve
+     * a consistent set of results.  This takes the shape of a loop.
      */
 
-    if ((statePtr->inputEncodingFlags & TCL_ENCODING_END) &&
-	    (bufPtr->nextPtr != NULL)) {
+    dstLimit = dstNeeded + 1;
+    while (1) {
+	int dstDecoded, dstRead, dstWrote, srcRead, numChars;
+
 	/*
-	 * TEE is set for a buffer which is not the last. Squash it for now,
-	 * and restore it later, before yielding control to our caller.
+	 * Perform the encoding transformation.  Read no more than
+	 * srcLen bytes, write no more than dstLimit bytes.
 	 */
 
-	statePtr->inputEncodingFlags &= ~TCL_ENCODING_END;
-	encEndFlagSuppressed = 1;
-    }
+	int code = Tcl_ExternalToUtf(NULL, encoding, src, srcLen,
+		statePtr->inputEncodingFlags & (bufPtr->nextPtr
+		? ~0 : ~TCL_ENCODING_END), &statePtr->inputEncodingState,
+		dst, dstLimit, &srcRead, &dstDecoded, &numChars);
 
-    oldState = statePtr->inputEncodingState;
-    if (GotFlag(statePtr, INPUT_NEED_NL)) {
 	/*
-	 * We want a '\n' because the last character we saw was '\r'.
+	 * Perform the translation transformation in place.  Read no more
+	 * than the dstDecoded bytes the encoding transformation actually
+	 * produced.  Capture the number of bytes written in dstWrote.
+	 * Capture the number of bytes actually consumed in dstRead.
 	 */
 
-	ResetFlag(statePtr, INPUT_NEED_NL);
-	Tcl_ExternalToUtf(NULL, statePtr->encoding, src, srcLen,
-		statePtr->inputEncodingFlags, &statePtr->inputEncodingState,
-		dst, TCL_UTF_MAX + 1, &srcRead, &dstWrote, &numChars);
-	if ((dstWrote > 0) && (*dst == '\n')) {
+	dstWrote = dstLimit;
+	dstRead = dstDecoded;
+	TranslateInputEOL(statePtr, dst, dst, &dstWrote, &dstRead);
+
+	if (dstRead < dstDecoded) {
+
 	    /*
-	     * The next char was a '\n'. Consume it and produce a '\n'.
+	     * The encoding transformation produced bytes that the
+	     * translation transformation did not consume.  Why did
+	     * this happen?
 	     */
 
-	    bufPtr->nextRemoved += srcRead;
-	} else {
+	    if (statePtr->inEofChar && dst[dstRead] == statePtr->inEofChar) {
+		/*
+		 * 1) There's an eof char set on the channel, and
+		 *    we saw it and stopped translating at that point.
+		 *
+		 * NOTE the bizarre spec of TranslateInputEOL in this case.
+		 * Clearly the eof char had to be read in order to account
+		 * for the stopping, but the value of dstRead does not
+		 * include it.
+		 *
+		 * Also rather bizarre, our caller can only notice an
+		 * EOF condition if we return the value -1 as the number
+		 * of chars read.  This forces us to perform a 2-call
+		 * dance where the first call can read all the chars
+		 * up to the eof char, and the second call is solely
+		 * for consuming the encoded eof char then pointed at
+		 * by src so that we can return that magic -1 value.
+		 * This seems really wasteful, especially since
+		 * the first decoding pass of each call is likely to
+		 * decode many bytes beyond that eof char that's all we
+		 * care about.
+		 */
+
+		if (dstRead == 0) {
+		    /*
+		     * Curious choice in the eof char handling.  We leave
+		     * the eof char in the buffer.  So, no need to compute
+		     * a proper srcRead value.  At this point, there
+		     * are no chars before the eof char in the buffer.
+		     */
+		    Tcl_SetObjLength(objPtr, numBytes);
+		    return -1;
+		}
+
+		{
+		    /*
+		     * There are chars leading the buffer before the eof
+		     * char.  Adjust the dstLimit so we go back and read
+		     * only those and do not encounter the eof char this
+		     * time.
+		     */
+
+		    dstLimit = dstRead + TCL_UTF_MAX;
+		    statePtr->flags = savedFlags;
+		    statePtr->inputEncodingFlags = savedIEFlags;
+		    statePtr->inputEncodingState = savedState;
+		    continue;
+		}
+	    }
+
 	    /*
-	     * The next char was not a '\n'. Produce a '\r'.
+	     * 2) The other way to read fewer bytes than are decoded
+	     *    is when the final byte is \r and we're in a CRLF
+	     *    translation mode so we cannot decide whether to
+	     *	  record \r or \n yet.
 	     */
 
-	    *dst = '\r';
-	}
-	statePtr->inputEncodingFlags &= ~TCL_ENCODING_START;
-	*offsetPtr += 1;
+	    assert(dst[dstRead] == '\r');
+	    assert(statePtr->inputTranslation == TCL_TRANSLATE_CRLF);
 
-	if (encEndFlagSuppressed) {
-	    statePtr->inputEncodingFlags |= TCL_ENCODING_END;
-	}
-	return 1;
-    }
+	    if (dstWrote > 0) {
+		/*
+		 * There are chars we can read before we hit the bare cr.
+		 * Go back with a smaller dstLimit so we get them in the
+		 * next pass, compute a matching srcRead, and don't end
+		 * up back here in this call.
+		 */
 
-    Tcl_ExternalToUtf(NULL, statePtr->encoding, src, srcLen,
-	    statePtr->inputEncodingFlags, &statePtr->inputEncodingState, dst,
-	    dstNeeded + 1, &srcRead, &dstWrote, &numChars);
+		dstLimit = dstRead + TCL_UTF_MAX;
+		statePtr->flags = savedFlags;
+		statePtr->inputEncodingFlags = savedIEFlags;
+		statePtr->inputEncodingState = savedState;
+		continue;
+	    }
 
-    if (encEndFlagSuppressed) {
-	statePtr->inputEncodingFlags |= TCL_ENCODING_END;
-    }
+	    assert(dstWrote == 0);
+	    assert(dstRead == 0);
 
-    if (srcRead == 0) {
-	/*
-	 * Not enough bytes in src buffer to make a complete char. Copy the
-	 * bytes to the next buffer to make a new contiguous string, then tell
-	 * the caller to fill the buffer with more bytes.
-	 */
+	    /*
+	     * We decoded only the bare cr, and we cannot read a
+	     * translated char from that alone.  We have to know what's
+	     * next.  So why do we only have the one decoded char?
+	     */
 
-	ChannelBuffer *nextPtr;
+	    if (code != TCL_OK) {
+		char buffer[TCL_UTF_MAX + 2];
+		int read, decoded, count;
+
+		/* 
+		 * Didn't get everything the buffer could offer
+		 */
+
+		statePtr->flags = savedFlags;
+		statePtr->inputEncodingFlags = savedIEFlags;
+		statePtr->inputEncodingState = savedState;
+
+		Tcl_ExternalToUtf(NULL, encoding, src, srcLen,
+		statePtr->inputEncodingFlags & (bufPtr->nextPtr
+		? ~0 : ~TCL_ENCODING_END), &statePtr->inputEncodingState,
+		buffer, TCL_UTF_MAX + 2, &read, &decoded, &count);
+
+		if (count == 2) {
+		    if (buffer[1] == '\n') {
+			/* \r\n translate to \n */
+			dst[0] = '\n';
+			bufPtr->nextRemoved += read;
+		    } else {
+			dst[0] = '\r';
+			bufPtr->nextRemoved += srcRead;
+		    }
+
+		    dst[1] = '\0';
+		    statePtr->inputEncodingFlags &= ~TCL_ENCODING_START;
+
+		    Tcl_SetObjLength(objPtr, numBytes + 1);
+		    return 1;
+		}
+
+	    } else if (statePtr->flags & CHANNEL_EOF) {
 
-	nextPtr = bufPtr->nextPtr;
-	if (nextPtr == NULL) {
-	    if (srcLen > 0) {
 		/*
-		 * There isn't enough data in the buffers to complete the next
-		 * character, so we need to wait for more data before the next
-		 * file event can be delivered. [Bug 478856]
-		 *
-		 * The exception to this is if the input buffer was completely
-		 * empty before we tried to convert its contents. Nothing in,
-		 * nothing out, and no incomplete character data. The
-		 * conversion before the current one was complete.
+		 * The bare \r is the only char and we will never read
+		 * a subsequent char to make the determination.
 		 */
 
-		SetFlag(statePtr, CHANNEL_NEED_MORE_DATA);
+		dst[0] = '\r';
+		bufPtr->nextRemoved = bufPtr->nextAdded;
+		Tcl_SetObjLength(objPtr, numBytes + 1);
+		return 1;
 	    }
-	    return -1;
+
+	    /*
+	     * Revise the dstRead value so that the numChars calc
+	     * below correctly computes zero characters read.
+	     */
+
+	    dstRead = numChars;
+
+	    /* FALL THROUGH - get more data (dstWrote == 0) */
 	}
 
-	/*
-	 * Space is made at the beginning of the buffer to copy the previous
-	 * unused bytes there. Check first if the buffer we are using actually
-	 * has enough space at its beginning for the data we are copying.
-	 * Because if not we will write over the buffer management
-	 * information, especially the 'nextPtr'.
-	 *
-	 * Note that the BUFFER_PADDING (See AllocChannelBuffer) is used to
-	 * prevent exactly this situation. I.e. it should never happen.
-	 * Therefore it is ok to panic should it happen despite the
-	 * precautions.
+	/* 
+	 * The translation transformation can only reduce the number
+	 * of chars when it converts \r\n into \n.  The reduction in
+	 * the number of chars is the difference in bytes read and written.
 	 */
 
-	if (nextPtr->nextRemoved - srcLen < 0) {
-	    Tcl_Panic("Buffer Underflow, BUFFER_PADDING not enough");
-	}
+	numChars -= (dstRead - dstWrote);
 
-	nextPtr->nextRemoved -= srcLen;
-	memcpy(RemovePoint(nextPtr), src, (size_t) srcLen);
-	RecycleBuffer(statePtr, bufPtr, 0);
-	statePtr->inQueueHead = nextPtr;
-	return ReadChars(statePtr, objPtr, charsToRead, offsetPtr, factorPtr);
-    }
+	if (charsToRead > 0 && numChars > charsToRead) {
 
-    dstRead = dstWrote;
-    if (TranslateInputEOL(statePtr, dst, dst, &dstWrote, &dstRead) != 0) {
-	/*
-	 * Hit EOF char. How many bytes of src correspond to where the EOF was
-	 * located in dst? Run the conversion again with an output buffer just
-	 * big enough to hold the data so we can get the correct value for
-	 * srcRead.
-	 */
+	    /* 
+	     * We read more chars than allowed.  Reset limits to
+	     * prevent that and try again.  Don't forget the extra
+	     * padding of TCL_UTF_MAX - 1 bytes demanded by the
+	     * Tcl_ExternalToUtf() call!
+	     */
 
-	if (dstWrote == 0) {
-	    return -1;
+	    dstLimit = Tcl_UtfAtIndex(dst, charsToRead + 1) 
+		    + TCL_UTF_MAX - 1 - dst;
+	    statePtr->flags = savedFlags;
+	    statePtr->inputEncodingFlags = savedIEFlags;
+	    statePtr->inputEncodingState = savedState;
+	    continue;
 	}
-	statePtr->inputEncodingState = oldState;
-	Tcl_ExternalToUtf(NULL, statePtr->encoding, src, srcLen,
-		statePtr->inputEncodingFlags, &statePtr->inputEncodingState,
-		dst, dstRead + TCL_UTF_MAX, &srcRead, &dstWrote, &numChars);
-	TranslateInputEOL(statePtr, dst, dst, &dstWrote, &dstRead);
-    }
 
-    /*
-     * The number of characters that we got may be less than the number that
-     * we started with because "\r\n" sequences may have been turned into just
-     * '\n' in dst.
-     */
+	if (dstWrote == 0) {
+	    ChannelBuffer *nextPtr;
 
-    numChars -= dstRead - dstWrote;
+	    /* We were not able to read any chars. */
 
-    if ((unsigned) numChars > (unsigned) toRead) {
-	/*
-	 * Got too many chars.
-	 */
+	    assert (numChars == 0);
+
+	    /* 
+	     * There is one situation where this is the correct final
+	     * result.  If the src buffer contains only a single \n
+	     * byte, and we are in TCL_TRANSLATE_AUTO mode, and
+	     * when the translation pass was made the INPUT_SAW_CR
+	     * flag was set on the channel.  In that case, the
+	     * correct behavior is to consume that \n and produce the
+	     * empty string.
+	     */
 
-	const char *eof = Tcl_UtfAtIndex(dst, toRead);
+	    if (dst[0] == '\n') {
+		assert(statePtr->inputTranslation == TCL_TRANSLATE_AUTO);
+		assert(dstRead == 1);
 
-	statePtr->inputEncodingState = oldState;
-	Tcl_ExternalToUtf(NULL, statePtr->encoding, src, srcLen,
-		statePtr->inputEncodingFlags, &statePtr->inputEncodingState,
-		dst, eof - dst + TCL_UTF_MAX, &srcRead, &dstWrote, &numChars);
-	dstRead = dstWrote;
-	TranslateInputEOL(statePtr, dst, dst, &dstWrote, &dstRead);
-	numChars -= (dstRead - dstWrote);
-    }
-    statePtr->inputEncodingFlags &= ~TCL_ENCODING_START;
+		goto consume;
+	    }
+
+	    /* Otherwise, reading zero characters indicates there's
+	     * something incomplete at the end of the src buffer.
+	     * Maybe there were not enough src bytes to decode into
+	     * a char.  Maybe a lone \r could not be translated (crlf
+	     * mode).  Need to combine any unused src bytes we have
+	     * in the first buffer with subsequent bytes to try again.
+	     */
+
+	    nextPtr = bufPtr->nextPtr;
+
+	    if (nextPtr == NULL) {
+		if (srcLen > 0) {
+		    SetFlag(statePtr, CHANNEL_NEED_MORE_DATA);
+		}
+		Tcl_SetObjLength(objPtr, numBytes);
+		return -1;
+	    }
+
+	    /*
+	     * Space is made at the beginning of the buffer to copy the
+	     * previous unused bytes there. Check first if the buffer we
+	     * are using actually has enough space at its beginning for
+	     * the data we are copying.  Because if not we will write over
+	     * the buffer management information, especially the 'nextPtr'.
+	     *
+	     * Note that the BUFFER_PADDING (See AllocChannelBuffer) is
+	     * used to prevent exactly this situation. I.e. it should never
+	     * happen.  Therefore it is ok to panic should it happen despite
+	     * the precautions.
+	     */
+
+	    if (nextPtr->nextRemoved - srcLen < 0) {
+		Tcl_Panic("Buffer Underflow, BUFFER_PADDING not enough");
+	    }
+
+	    nextPtr->nextRemoved -= srcLen;
+	    memcpy(RemovePoint(nextPtr), src, (size_t) srcLen);
+	    RecycleBuffer(statePtr, bufPtr, 0);
+	    statePtr->inQueueHead = nextPtr;
+	    Tcl_SetObjLength(objPtr, numBytes);
+	    return ReadChars(statePtr, objPtr, charsToRead, factorPtr);
+	}
+
+	statePtr->inputEncodingFlags &= ~TCL_ENCODING_START;
 
-    bufPtr->nextRemoved += srcRead;
-    if (dstWrote > srcRead + 1) {
-	*factorPtr = dstWrote * UTF_EXPANSION_FACTOR / srcRead;
+    consume:
+	bufPtr->nextRemoved += srcRead;
+	/*
+	 * If this read contained multibyte characters, revise factorPtr
+	 * so the next read will allocate bigger buffers.
+	 */
+	if (numChars && numChars < srcRead) {
+	    *factorPtr = srcRead * UTF_EXPANSION_FACTOR / numChars;
+	}
+	Tcl_SetObjLength(objPtr, numBytes + dstWrote);
+	return numChars;
     }
-    *offsetPtr += dstWrote;
-    return numChars;
 }
 
 /*
@@ -6015,7 +6142,7 @@ ReadChars(
  *---------------------------------------------------------------------------
  */
 
-static int
+static void 
 TranslateInputEOL(
     ChannelState *statePtr,	/* Channel being read, for EOL translation and
 				 * EOF character. */
@@ -6024,132 +6151,138 @@ TranslateInputEOL(
 				 * characters. */
     const char *srcStart,	/* Source characters. */
     int *dstLenPtr,		/* On entry, the maximum length of output
-				 * buffer in bytes; must be <= *srcLenPtr. On
-				 * exit, the number of bytes actually used in
-				 * output buffer. */
+				 * buffer in bytes. On exit, the number of
+				 * bytes actually used in output buffer. */
     int *srcLenPtr)		/* On entry, the length of source buffer. On
 				 * exit, the number of bytes read from the
 				 * source buffer. */
 {
-    int dstLen, srcLen, inEofChar;
-    const char *eof;
+    const char *eof = NULL;
+    int dstLen = *dstLenPtr;
+    int srcLen = *srcLenPtr;
+    int inEofChar = statePtr->inEofChar;
 
-    dstLen = *dstLenPtr;
+    /*
+     * Depending on the translation mode in use, there's no need
+     * to scan more srcLen bytes at srcStart than can possibly transform
+     * to dstLen bytes.  This keeps the scan for eof char below from
+     * being pointlessly long.
+     */
+
+    switch (statePtr->inputTranslation) {
+    case TCL_TRANSLATE_LF:
+    case TCL_TRANSLATE_CR:
+	if (srcLen > dstLen) {
+	/* In these modes, each src byte become a dst byte. */
+	    srcLen = dstLen;
+	}
+	break;
+    default:
+	/* In other modes, at most 2 src bytes become a dst byte. */
+	if (srcLen > 2 * dstLen) {
+	    srcLen = 2 * dstLen;
+	}
+	break;
+    }
 
-    eof = NULL;
-    inEofChar = statePtr->inEofChar;
     if (inEofChar != '\0') {
 	/*
-	 * Find EOF in translated buffer then compress out the EOL. The source
-	 * buffer may be much longer than the destination buffer - we only
-	 * want to return EOF if the EOF has been copied to the destination
-	 * buffer.
+	 * Make sure we do not read past any logical end of channel input
+	 * created by the presence of the input eof char.
 	 */
 
-	const char *src, *srcMax = srcStart + *srcLenPtr;
-
-	for (src = srcStart; src < srcMax; src++) {
-	    if (*src == inEofChar) {
-		eof = src;
-		srcLen = src - srcStart;
-		if (srcLen < dstLen) {
-		    dstLen = srcLen;
-		}
-		*srcLenPtr = srcLen;
-		break;
-	    }
+	if ((eof = memchr(srcStart, inEofChar, srcLen))) {
+	    srcLen = eof - srcStart;
 	}
     }
+
     switch (statePtr->inputTranslation) {
     case TCL_TRANSLATE_LF:
+    case TCL_TRANSLATE_CR:
 	if (dstStart != srcStart) {
-	    memcpy(dstStart, srcStart, (size_t) dstLen);
+	    memcpy(dstStart, srcStart, (size_t) srcLen);
 	}
-	srcLen = dstLen;
-	break;
-    case TCL_TRANSLATE_CR: {
-	char *dst, *dstEnd;
+	if (statePtr->inputTranslation == TCL_TRANSLATE_CR) {
+	    char *dst = dstStart;
+	    char *dstEnd = dstStart + srcLen;
 
-	if (dstStart != srcStart) {
-	    memcpy(dstStart, srcStart, (size_t) dstLen);
-	}
-	dstEnd = dstStart + dstLen;
-	for (dst = dstStart; dst < dstEnd; dst++) {
-	    if (*dst == '\r') {
-		*dst = '\n';
+	    while ((dst = memchr(dst, '\r', dstEnd - dst))) {
+		*dst++ = '\n';
 	    }
 	}
-	srcLen = dstLen;
+	dstLen = srcLen;
 	break;
-    }
     case TCL_TRANSLATE_CRLF: {
-	char *dst;
-	const char *src, *srcEnd, *srcMax;
-
-	dst = dstStart;
-	src = srcStart;
-	srcEnd = srcStart + dstLen;
-	srcMax = srcStart + *srcLenPtr;
-
-	for ( ; src < srcEnd; ) {
-	    if (*src == '\r') {
-		src++;
-		if (src >= srcMax) {
-		    SetFlag(statePtr, INPUT_NEED_NL);
-		} else if (*src == '\n') {
-		    *dst++ = *src++;
-		} else {
+	const char *crFound, *src = srcStart;
+	char *dst = dstStart;
+	int lesser = (dstLen < srcLen) ? dstLen : srcLen;
+
+	while ((crFound = memchr(src, '\r', lesser))) {
+	    int numBytes = crFound - src;
+	    memmove(dst, src, numBytes);
+
+	    dst += numBytes; dstLen -= numBytes;
+	    src += numBytes; srcLen -= numBytes;
+	    if (srcLen == 1) {
+		/* valid src bytes end in \r */
+		if (eof) {
 		    *dst++ = '\r';
+		    src++; srcLen--;
+		} else {
+		    lesser = 0;
+		    break;
 		}
+	    } else if (src[1] == '\n') {
+		*dst++ = '\n';
+		src += 2; srcLen -= 2;
 	    } else {
-		*dst++ = *src++;
+		*dst++ = '\r';
+		src++; srcLen--;
 	    }
+	    dstLen--;
+	    lesser = (dstLen < srcLen) ? dstLen : srcLen;
 	}
-	srcLen = src - srcStart;
-	dstLen = dst - dstStart;
+	memmove(dst, src, lesser);
+	srcLen = src + lesser - srcStart;
+	dstLen = dst + lesser - dstStart;
 	break;
     }
     case TCL_TRANSLATE_AUTO: {
-	char *dst;
-	const char *src, *srcEnd, *srcMax;
+	const char *crFound, *src = srcStart;
+	char *dst = dstStart;
+	int lesser;
 
-	dst = dstStart;
-	src = srcStart;
-	srcEnd = srcStart + dstLen;
-	srcMax = srcStart + *srcLenPtr;
-
-	if (GotFlag(statePtr, INPUT_SAW_CR) && (src < srcMax)) {
-	    if (*src == '\n') {
-		src++;
-	    }
+	if ((statePtr->flags & INPUT_SAW_CR) && srcLen) {
+	    if (*src == '\n') { src++; srcLen--; }
 	    ResetFlag(statePtr, INPUT_SAW_CR);
 	}
-	for ( ; src < srcEnd; ) {
-	    if (*src == '\r') {
-		src++;
-		if (src >= srcMax) {
-		    SetFlag(statePtr, INPUT_SAW_CR);
-		} else if (*src == '\n') {
-		    if (srcEnd < srcMax) {
-			srcEnd++;
-		    }
-		    src++;
-		}
-		*dst++ = '\n';
-	    } else {
-		*dst++ = *src++;
+	lesser = (dstLen < srcLen) ? dstLen : srcLen;
+	while ((crFound = memchr(src, '\r', lesser))) {
+	    int numBytes = crFound - src;
+	    memmove(dst, src, numBytes);
+
+	    dst[numBytes] = '\n';
+	    dst += numBytes + 1; dstLen -= numBytes + 1;
+	    src += numBytes + 1; srcLen -= numBytes + 1;
+	    if (srcLen == 0) {
+		SetFlag(statePtr, INPUT_SAW_CR);
+	    } else if (*src == '\n') {
+		src++; srcLen--;
 	    }
+	    lesser = (dstLen < srcLen) ? dstLen : srcLen;
 	}
-	srcLen = src - srcStart;
-	dstLen = dst - dstStart;
+	memmove(dst, src, lesser);
+	srcLen = src + lesser - srcStart;
+	dstLen = dst + lesser - dstStart;
 	break;
     }
     default:
-	return 0;
+	Tcl_Panic("unknown input translation %d", statePtr->inputTranslation);
     }
     *dstLenPtr = dstLen;
+    *srcLenPtr = srcLen;
 
-    if ((eof != NULL) && (srcStart + srcLen >= eof)) {
+    if (srcStart + srcLen == eof) {
 	/*
 	 * EOF character was seen in EOL translated range. Leave current file
 	 * position pointing at the EOF character, but don't store the EOF
@@ -6158,12 +6291,8 @@ TranslateInputEOL(
 
 	SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF);
 	statePtr->inputEncodingFlags |= TCL_ENCODING_END;
-	ResetFlag(statePtr, INPUT_SAW_CR | INPUT_NEED_NL);
-	return 1;
+	ResetFlag(statePtr, INPUT_SAW_CR);
     }
-
-    *srcLenPtr = srcLen;
-    return 0;
 }
 
 /*
@@ -6217,16 +6346,11 @@ Tcl_Ungets(
     statePtr->flags = flags;
 
     /*
-     * If we have encountered a sticky EOF, just punt without storing (sticky
-     * EOF is set if we have seen the input eofChar, to prevent reading beyond
-     * the eofChar). Otherwise, clear the EOF flags, and clear the BLOCKED
-     * bit. We want to discover these conditions anew in each operation.
+     * Clear the EOF flags, and clear the BLOCKED bit.
      */
 
-    if (GotFlag(statePtr, CHANNEL_STICKY_EOF)) {
-	goto done;
-    }
-    ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_EOF);
+    ResetFlag(statePtr,
+	    CHANNEL_BLOCKED | CHANNEL_STICKY_EOF | CHANNEL_EOF | INPUT_SAW_CR);
 
     bufPtr = AllocChannelBuffer(len);
     memcpy(InsertPoint(bufPtr), str, (size_t) len);
@@ -6291,14 +6415,6 @@ Tcl_Flush(
 	return -1;
     }
 
-    /*
-     * Force current output buffer to be output also.
-     */
-
-    if ((statePtr->curOutPtr != NULL) && IsBufferReady(statePtr->curOutPtr)) {
-	SetFlag(statePtr, BUFFER_READY);
-    }
-
     result = FlushChannel(NULL, chanPtr, 0);
     if (result != 0) {
 	return TCL_ERROR;
@@ -6349,7 +6465,7 @@ DiscardInputQueued(
      */
 
     if (discardSavedBuffers && statePtr->saveInBufPtr != NULL) {
-	ckfree(statePtr->saveInBufPtr);
+	ReleaseChannelBuffer(statePtr->saveInBufPtr);
 	statePtr->saveInBufPtr = NULL;
     }
 }
@@ -6361,6 +6477,9 @@ DiscardInputQueued(
  *
  *	Reads input data from a device into a channel buffer.
  *
+ *	IMPORTANT!  This routine is only called on a chanPtr argument
+ *	that is the top channel of a stack!
+ *
  * Results:
  *	The return value is the Posix error code if an error occurred while
  *	reading from the file, or 0 otherwise.
@@ -6393,21 +6512,28 @@ GetInput(
 	return EINVAL;
     }
 
+    /* 
+     * For a channel at EOF do not bother allocating buffers; there's
+     * nothing more to read.  Avoid calling the driver inputproc in
+     * case some of them do not react well to additional calls after
+     * they've reported an eof state..
+     * TODO: Candidate for a can't happen panic.
+     */
+
+    if (GotFlag(statePtr, CHANNEL_EOF)) {
+	return 0;
+    }
+
     /*
      * First check for more buffers in the pushback area of the topmost
      * channel in the stack and use them. They can be the result of a
      * transformation which went away without reading all the information
      * placed in the area when it was stacked.
-     *
-     * Two possibilities for the state: No buffers in it, or a single empty
-     * buffer. In the latter case we can recycle it now.
      */
 
     if (chanPtr->inQueueHead != NULL) {
-	if (statePtr->inQueueHead != NULL) {
-	    RecycleBuffer(statePtr, statePtr->inQueueHead, 0);
-	    statePtr->inQueueHead = NULL;
-	}
+
+	assert(statePtr->inQueueHead == NULL);
 
 	statePtr->inQueueHead = chanPtr->inQueueHead;
 	statePtr->inQueueTail = chanPtr->inQueueTail;
@@ -6428,21 +6554,20 @@ GetInput(
      */
 
     bufPtr = statePtr->inQueueTail;
-    if ((bufPtr != NULL) && !IsBufferFull(bufPtr)) {
-	toRead = SpaceLeft(bufPtr);
-    } else {
+
+    if ((bufPtr == NULL) || IsBufferFull(bufPtr)) {
 	bufPtr = statePtr->saveInBufPtr;
 	statePtr->saveInBufPtr = NULL;
 
 	/*
 	 * Check the actual buffersize against the requested buffersize.
-	 * Buffers which are smaller than requested are squashed. This is done
+	 * Saved buffers of the wrong size are squashed. This is done
 	 * to honor dynamic changes of the buffersize made by the user.
 	 */
 
 	if ((bufPtr != NULL)
-		&& (bufPtr->bufLength - BUFFER_PADDING < statePtr->bufSize)) {
-	    ckfree(bufPtr);
+		&& (bufPtr->bufLength - BUFFER_PADDING != statePtr->bufSize)) {
+	    ReleaseChannelBuffer(bufPtr);
 	    bufPtr = NULL;
 	}
 
@@ -6451,21 +6576,8 @@ GetInput(
 	}
 	bufPtr->nextPtr = NULL;
 
-	/*
-	 * SF #427196: Use the actual size of the buffer to determine the
-	 * number of bytes to read from the channel and not the size for new
-	 * buffers. They can be different if the buffersize was changed
-	 * between reads.
-	 *
-	 * Note: This affects performance negatively if the buffersize was
-	 * extended but this small buffer is reused for all subsequent reads.
-	 * The system never uses buffers with the requested bigger size in
-	 * that case. An adjunct patch could try and delete all unused buffers
-	 * it encounters and which are smaller than the formally requested
-	 * buffersize.
-	 */
-
 	toRead = SpaceLeft(bufPtr);
+	assert(toRead == statePtr->bufSize);
 
 	if (statePtr->inQueueTail == NULL) {
 	    statePtr->inQueueHead = bufPtr;
@@ -6473,75 +6585,22 @@ GetInput(
 	    statePtr->inQueueTail->nextPtr = bufPtr;
 	}
 	statePtr->inQueueTail = bufPtr;
+    } else {
+	toRead = SpaceLeft(bufPtr);
     }
 
-    /*
-     * If EOF is set, we should avoid calling the driver because on some
-     * platforms it is impossible to read from a device after EOF.
-     */
-
-    if (GotFlag(statePtr, CHANNEL_EOF)) {
-	return 0;
-    }
-
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-    /*
-     * [Bug 943274]: Better emulation of non-blocking channels for channels
-     * without BlockModeProc, by keeping track of true fileevents generated by
-     * the OS == Data waiting and reading if and only if we are sure to have
-     * data.
-     */
-
-    if (GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
-	    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
-	    !GotFlag(statePtr, CHANNEL_HAS_MORE_DATA)) {
-	/*
-	 * Bypass the driver, it would block, as no data is available
-	 */
+    PreserveChannelBuffer(bufPtr);
+    nread = ChanRead(chanPtr, InsertPoint(bufPtr), toRead);
 
-	nread = -1;
-	result = EWOULDBLOCK;
-    } else
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-    {
-	nread = ChanRead(chanPtr, InsertPoint(bufPtr), toRead, &result);
-    }
-
-    if (nread > 0) {
+    if (nread < 0) {
+	result = Tcl_GetErrno();
+    } else {
+	result = 0;
 	bufPtr->nextAdded += nread;
-
-	/*
-	 * If we get a short read, signal up that we may be BLOCKED. We should
-	 * avoid calling the driver because on some platforms we will block in
-	 * the low level reading code even though the channel is set into
-	 * nonblocking mode.
-	 */
-
-	if (nread < toRead) {
-	    SetFlag(statePtr, CHANNEL_BLOCKED);
-	}
-
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-	if (nread <= toRead) {
-	    /*
-	     * [Bug 943274]: We have read the available data, clear flag.
-	     */
-
-	    ResetFlag(statePtr, CHANNEL_HAS_MORE_DATA);
-	}
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-    } else if (nread == 0) {
-	SetFlag(statePtr, CHANNEL_EOF);
-	statePtr->inputEncodingFlags |= TCL_ENCODING_END;
-    } else if (nread < 0) {
-	if ((result == EWOULDBLOCK) || (result == EAGAIN)) {
-	    SetFlag(statePtr, CHANNEL_BLOCKED);
-	    result = EAGAIN;
-	}
-	Tcl_SetErrno(result);
-	return result;
     }
-    return 0;
+
+    ReleaseChannelBuffer(bufPtr);
+    return result;
 }
 
 /*
@@ -6669,15 +6728,6 @@ Tcl_Seek(
     }
 
     /*
-     * If there is data buffered in statePtr->curOutPtr then mark the channel
-     * as ready to flush before invoking FlushChannel.
-     */
-
-    if ((statePtr->curOutPtr != NULL) && IsBufferReady(statePtr->curOutPtr)) {
-	SetFlag(statePtr, BUFFER_READY);
-    }
-
-    /*
      * If the flush fails we cannot recover the original position. In that
      * case the seek is not attempted because we do not know where the access
      * position is - instead we return the error. FlushChannel has already
@@ -7001,17 +7051,7 @@ CheckChannelErrors(
     }
 
     if (direction == TCL_READABLE) {
-	/*
-	 * If we have not encountered a sticky EOF, clear the EOF bit (sticky
-	 * EOF is set if we have seen the input eofChar, to prevent reading
-	 * beyond the eofChar). Also, always clear the BLOCKED bit. We want to
-	 * discover these conditions anew in each operation.
-	 */
-
-	if (!GotFlag(statePtr, CHANNEL_STICKY_EOF)) {
-	    ResetFlag(statePtr, CHANNEL_EOF);
-	}
-	ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_NEED_MORE_DATA);
+	ResetFlag(statePtr, CHANNEL_NEED_MORE_DATA);
     }
 
     return 0;
@@ -7227,7 +7267,27 @@ Tcl_SetChannelBufferSize(
     }
 
     statePtr = ((Channel *) chan)->state;
+
+    if (statePtr->bufSize == sz) {
+	return;
+    }
     statePtr->bufSize = sz;
+
+    /*
+     * If bufsize changes, need to get rid of old utility buffer.
+     */
+
+    if (statePtr->saveInBufPtr != NULL) {
+	RecycleBuffer(statePtr, statePtr->saveInBufPtr, 1);
+	statePtr->saveInBufPtr = NULL;
+    }
+    if ((statePtr->inQueueHead != NULL)
+	    && (statePtr->inQueueHead->nextPtr == NULL)
+	    && IsBufferEmpty(statePtr->inQueueHead)) {
+	RecycleBuffer(statePtr, statePtr->inQueueHead, 1);
+	statePtr->inQueueHead = NULL;
+	statePtr->inQueueTail = NULL;
+    }
 }
 
 /*
@@ -7662,6 +7722,7 @@ Tcl_SetChannelOption(
 	    return TCL_ERROR;
 	}
 	Tcl_SetChannelBufferSize(chan, newBufferSize);
+	return TCL_OK;
     } else if (HaveOpt(2, "-encoding")) {
 	Tcl_Encoding encoding;
 
@@ -7679,7 +7740,8 @@ Tcl_SetChannelOption(
 	 * iso2022, the terminated escape sequence must write to the buffer.
 	 */
 
-	if ((statePtr->encoding != NULL) && (statePtr->curOutPtr != NULL)
+	if ((statePtr->encoding != NULL)
+		&& !(statePtr->outputEncodingFlags & TCL_ENCODING_START)
 		&& (CheckChannelErrors(statePtr, TCL_WRITABLE) == 0)) {
 	    statePtr->outputEncodingFlags |= TCL_ENCODING_END;
 	    WriteChars(chanPtr, "", 0);
@@ -7692,6 +7754,7 @@ Tcl_SetChannelOption(
 	statePtr->outputEncodingFlags = TCL_ENCODING_START;
 	ResetFlag(statePtr, CHANNEL_NEED_MORE_DATA);
 	UpdateInterest(chanPtr);
+	return TCL_OK;
     } else if (HaveOpt(2, "-eofchar")) {
 	if (Tcl_SplitList(interp, newValue, &argc, &argv) == TCL_ERROR) {
 	    return TCL_ERROR;
@@ -7852,22 +7915,6 @@ Tcl_SetChannelOption(
 	return Tcl_BadChannelOption(interp, optionName, NULL);
     }
 
-    /*
-     * If bufsize changes, need to get rid of old utility buffer.
-     */
-
-    if (statePtr->saveInBufPtr != NULL) {
-	RecycleBuffer(statePtr, statePtr->saveInBufPtr, 1);
-	statePtr->saveInBufPtr = NULL;
-    }
-    if ((statePtr->inQueueHead != NULL)
-	    && (statePtr->inQueueHead->nextPtr == NULL)
-	    && IsBufferEmpty(statePtr->inQueueHead)) {
-	RecycleBuffer(statePtr, statePtr->inQueueHead, 1);
-	statePtr->inQueueHead = NULL;
-	statePtr->inQueueTail = NULL;
-    }
-
     return TCL_OK;
 }
 
@@ -7959,21 +8006,6 @@ Tcl_NotifyChannel(
     Channel *upChanPtr;
     const Tcl_ChannelType *upTypePtr;
 
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-    /*
-     * [SF Tcl Bug 943274] For a non-blocking channel without blockmodeproc we
-     * keep track of actual input coming from the OS so that we can do a
-     * credible imitation of non-blocking behaviour.
-     */
-
-    if ((mask & TCL_READABLE) &&
-	    GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
-	    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
-	    !GotFlag(statePtr, CHANNEL_TIMER_FEV)) {
-	SetFlag(statePtr, CHANNEL_HAS_MORE_DATA);
-    }
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-
     /*
      * In contrast to the other API functions this procedure walks towards the
      * top of a stack and not down from it.
@@ -8033,8 +8065,9 @@ Tcl_NotifyChannel(
      */
 
     if (GotFlag(statePtr, BG_FLUSH_SCHEDULED) && (mask & TCL_WRITABLE)) {
-	FlushChannel(NULL, chanPtr, 1);
-	mask &= ~TCL_WRITABLE;
+	if (0 == FlushChannel(NULL, chanPtr, 1)) {
+	    mask &= ~TCL_WRITABLE;
+	}
     }
 
     /*
@@ -8102,6 +8135,11 @@ UpdateInterest(
 				/* State info for channel */
     int mask = statePtr->interestMask;
 
+    if (chanPtr->typePtr == NULL) {
+	/* Do not update interest on a closed channel */
+	return;
+    }
+
     /*
      * If there are flushed buffers waiting to be written, then we need to
      * watch for the channel to become writable.
@@ -8209,29 +8247,8 @@ ChannelTimerProc(
 
 	statePtr->timer = Tcl_CreateTimerHandler(SYNTHETIC_EVENT_TIME,
                 ChannelTimerProc,chanPtr);
-
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-	/*
-	 * Set the TIMER flag to notify the higher levels that the driver
-	 * might have no data for us. We do this only if we are in
-	 * non-blocking mode and the driver has no BlockModeProc because only
-	 * then we really don't know if the driver will block or not. A
-	 * similar test is done in "PeekAhead".
-	 */
-
-	if (GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
-		(Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL)) {
-	    SetFlag(statePtr, CHANNEL_TIMER_FEV);
-	}
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-
 	Tcl_Preserve(statePtr);
 	Tcl_NotifyChannel((Tcl_Channel) chanPtr, TCL_READABLE);
-
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-	ResetFlag(statePtr, CHANNEL_TIMER_FEV);
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-
 	Tcl_Release(statePtr);
     } else {
 	statePtr->timer = NULL;
@@ -9171,12 +9188,23 @@ CopyData(
  *
  * DoRead --
  *
- *	Reads a given number of bytes from a channel. No encoding conversions
+ *	Stores up to "bytesToRead" bytes in memory pointed to by "dst".
+ *	These bytes come from reading the channel "chanPtr" and 
+ *	performing the configured translations.  No encoding conversions
  *	are applied to the bytes being read.
  *
  * Results:
- *	The number of characters read, or -1 on error. Use Tcl_GetErrno() to
- *	retrieve the error code for the error that occurred.
+ *	The number of bytes actually stored (<= bytesToRead),
+ * 	or -1 if there is an error in reading the channel.  Use
+ * 	Tcl_GetErrno() to retrieve the error code for the error
+ *	that occurred.
+ *
+ *	The number of bytes stored can be less than the number
+ * 	requested when
+ *	  - EOF is reached on the channel; or
+ *	  - the channel is non-blocking, and we've read all we can
+ *	    without blocking.
+ *	  - a channel reading error occurs (and we return -1)
  *
  * Side effects:
  *	May cause input to be buffered.
@@ -9187,382 +9215,152 @@ CopyData(
 static int
 DoRead(
     Channel *chanPtr,		/* The channel from which to read. */
-    char *bufPtr,		/* Where to store input read. */
-    int toRead,			/* Maximum number of bytes to read. */
+    char *dst,			/* Where to store input read. */
+    int bytesToRead,		/* Maximum number of bytes to read. */
     int allowShortReads)	/* Allow half-blocking (pipes,sockets) */
 {
     ChannelState *statePtr = chanPtr->state;
-				/* State info for channel */
-    int copied;			/* How many characters were copied into the
-				 * result string? */
-    int copiedNow;		/* How many characters were copied from the
-				 * current input buffer? */
-    int result;			/* Of calling GetInput. */
-
-    /*
-     * If we have not encountered a sticky EOF, clear the EOF bit. Either way
-     * clear the BLOCKED bit. We want to discover these anew during each
-     * operation.
-     */
-
-    if (!GotFlag(statePtr, CHANNEL_STICKY_EOF)) {
-	ResetFlag(statePtr, CHANNEL_EOF);
-    }
-    ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_NEED_MORE_DATA);
-
-    for (copied = 0; copied < toRead; copied += copiedNow) {
-	copiedNow = CopyAndTranslateBuffer(statePtr, bufPtr + copied,
-		toRead - copied);
-	if (copiedNow == 0) {
-	    if (GotFlag(statePtr, CHANNEL_EOF)) {
-		goto done;
-	    }
-	    if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
-		if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
-		    goto done;
-		}
-		ResetFlag(statePtr, CHANNEL_BLOCKED);
-	    }
-	    result = GetInput(chanPtr);
-	    if (result != 0) {
-		if (result != EAGAIN) {
-		    copied = -1;
-		}
-		goto done;
-	    }
-	} else if (allowShortReads) {
-            copied += copiedNow;
-            break;
-        }
-    }
-
-    ResetFlag(statePtr, CHANNEL_BLOCKED);
-
-    /*
-     * Update the notifier state so we don't block while there is still data
-     * in the buffers.
-     */
-
-  done:
-    UpdateInterest(chanPtr);
-    return copied;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * CopyAndTranslateBuffer --
- *
- *	Copy at most one buffer of input to the result space, doing eol
- *	translations according to mode in effect currently.
- *
- * Results:
- *	Number of bytes stored in the result buffer (as opposed to the number
- *	of bytes read from the channel). May return zero if no input is
- *	available to be translated.
- *
- * Side effects:
- *	Consumes buffered input. May deallocate one buffer.
- *
- *----------------------------------------------------------------------
- */
-
-static int
-CopyAndTranslateBuffer(
-    ChannelState *statePtr,	/* Channel state from which to read input. */
-    char *result,		/* Where to store the copied input. */
-    int space)			/* How many bytes are available in result to
-				 * store the copied input? */
-{
-    ChannelBuffer *bufPtr;	/* The buffer from which to copy bytes. */
-    int bytesInBuffer;		/* How many bytes are available to be copied
-				 * in the current input buffer? */
-    int copied;			/* How many characters were already copied
-				 * into the destination space? */
-    int i;			/* Iterates over the copied input looking for
-				 * the input eofChar. */
-
-    /*
-     * If there is no input at all, return zero. The invariant is that either
-     * there is no buffer in the queue, or if the first buffer is empty, it is
-     * also the last buffer (and thus there is no input in the queue). Note
-     * also that if the buffer is empty, we leave it in the queue.
-     */
-
-    if (statePtr->inQueueHead == NULL) {
-	return 0;
-    }
-    bufPtr = statePtr->inQueueHead;
-    bytesInBuffer = BytesLeft(bufPtr);
-
-    copied = 0;
-    switch (statePtr->inputTranslation) {
-    case TCL_TRANSLATE_LF:
-	if (bytesInBuffer == 0) {
-	    return 0;
-	}
+    char *p = dst;
 
+    Tcl_Preserve(chanPtr);
+    while (bytesToRead) {
 	/*
-	 * Copy the current chunk into the result buffer.
+	 * Each pass through the loop is intended to process up to 
+	 * one channel buffer.
 	 */
 
-	if (bytesInBuffer < space) {
-	    space = bytesInBuffer;
-	}
-	memcpy(result, RemovePoint(bufPtr), (size_t) space);
-	bufPtr->nextRemoved += space;
-	copied = space;
-	break;
-    case TCL_TRANSLATE_CR: {
-	char *end;
-
-	if (bytesInBuffer == 0) {
-	    return 0;
-	}
+	int bytesRead, bytesWritten;
+	ChannelBuffer *bufPtr = statePtr->inQueueHead;
 
 	/*
-	 * Copy the current chunk into the result buffer, then replace all \r
-	 * with \n.
+	 * When there's no buffered data to read, and we're at EOF,
+	 * escape to the caller.
 	 */
 
-	if (bytesInBuffer < space) {
-	    space = bytesInBuffer;
-	}
-	memcpy(result, RemovePoint(bufPtr), (size_t) space);
-	bufPtr->nextRemoved += space;
-	copied = space;
-
-	for (end = result + copied; result < end; result++) {
-	    if (*result == '\r') {
-		*result = '\n';
-	    }
+	if (statePtr->flags & CHANNEL_EOF
+		&& (bufPtr == NULL || IsBufferEmpty(bufPtr))) {
+	    break;
 	}
-	break;
-    }
-    case TCL_TRANSLATE_CRLF: {
-	char *src, *end, *dst;
-	int curByte;
 
-	/*
-	 * If there is a held-back "\r" at EOF, produce it now.
-	 */
+	/* If there is no full buffer, attempt to create and/or fill one. */
 
-	if (bytesInBuffer == 0) {
-	    if ((statePtr->flags & (INPUT_SAW_CR | CHANNEL_EOF)) ==
-		    (INPUT_SAW_CR | CHANNEL_EOF)) {
-		result[0] = '\r';
-		ResetFlag(statePtr, INPUT_SAW_CR);
-		return 1;
-	    }
-	    return 0;
-	}
+	while (!IsBufferFull(bufPtr)) {
+	    int code;
 
-	/*
-	 * Copy the current chunk and replace "\r\n" with "\n" (but not
-	 * standalone "\r"!).
-	 */
+	moreData:
+	    code = GetInput(chanPtr);
+	    bufPtr = statePtr->inQueueHead;
 
-	if (bytesInBuffer < space) {
-	    space = bytesInBuffer;
-	}
-	memcpy(result, RemovePoint(bufPtr), (size_t) space);
-	bufPtr->nextRemoved += space;
-	copied = space;
+	    assert (bufPtr != NULL);
 
-	end = result + copied;
-	dst = result;
-	for (src = result; src < end; src++) {
-	    curByte = *src;
-	    if (curByte == '\n') {
-		ResetFlag(statePtr, INPUT_SAW_CR);
-	    } else if (GotFlag(statePtr, INPUT_SAW_CR)) {
-		ResetFlag(statePtr, INPUT_SAW_CR);
-		*dst = '\r';
-		dst++;
+	    if (statePtr->flags & (CHANNEL_EOF|CHANNEL_BLOCKED)) {
+		/* Further reads cannot do any more */
+		break;
 	    }
-	    if (curByte == '\r') {
-		SetFlag(statePtr, INPUT_SAW_CR);
-	    } else {
-		*dst = (char) curByte;
-		dst++;
+	    
+	    if (code) {
+		/* Read error */
+		UpdateInterest(chanPtr);
+		Tcl_Release(chanPtr);
+		return -1;
 	    }
-	}
-	copied = dst - result;
-	break;
-    }
-    case TCL_TRANSLATE_AUTO: {
-	char *src, *end, *dst;
-	int curByte;
 
-	if (bytesInBuffer == 0) {
-	    return 0;
+	    assert (IsBufferFull(bufPtr));
 	}
 
-	/*
-	 * Loop over the current buffer, converting "\r" and "\r\n" to "\n".
-	 */
+	assert (bufPtr != NULL);
 
-	if (bytesInBuffer < space) {
-	    space = bytesInBuffer;
-	}
-	memcpy(result, RemovePoint(bufPtr), (size_t) space);
-	bufPtr->nextRemoved += space;
-	copied = space;
+	bytesRead = BytesLeft(bufPtr);
+	bytesWritten = bytesToRead;
 
-	end = result + copied;
-	dst = result;
-	for (src = result; src < end; src++) {
-	    curByte = *src;
-	    if (curByte == '\r') {
-		SetFlag(statePtr, INPUT_SAW_CR);
-		*dst = '\n';
-		dst++;
-	    } else {
-		if ((curByte != '\n') || !GotFlag(statePtr, INPUT_SAW_CR)) {
-		    *dst = (char) curByte;
-		    dst++;
-		}
-		ResetFlag(statePtr, INPUT_SAW_CR);
-	    }
-	}
-	copied = dst - result;
-	break;
-    }
-    default:
-	Tcl_Panic("unknown eol translation mode");
-    }
-
-    /*
-     * If an in-stream EOF character is set for this channel, check that the
-     * input we copied so far does not contain the EOF char. If it does, copy
-     * only up to and excluding that character.
-     */
+	TranslateInputEOL(statePtr, p, RemovePoint(bufPtr),
+		&bytesWritten, &bytesRead);
+	bufPtr->nextRemoved += bytesRead;
+	p += bytesWritten;
+	bytesToRead -= bytesWritten;
 
-    if (statePtr->inEofChar != 0) {
-	for (i = 0; i < copied; i++) {
-	    if (result[i] == (char) statePtr->inEofChar) {
-		/*
-		 * Set sticky EOF so that no further input is presented to the
-		 * caller.
-		 */
+	if (!IsBufferEmpty(bufPtr)) {
+	    /*
+	     * Buffer is not empty.  How can that be?
+	     *
+	     * 0) We stopped early because we got all the bytes
+	     *    we were seeking.  That's fine.
+	     */
 
-		SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF);
-		statePtr->inputEncodingFlags |= TCL_ENCODING_END;
-		copied = i;
+	    if (bytesToRead == 0) {
+		UpdateInterest(chanPtr);
 		break;
 	    }
-	}
-    }
-
-    /*
-     * If the current buffer is empty recycle it.
-     */
-
-    if (IsBufferEmpty(bufPtr)) {
-	statePtr->inQueueHead = bufPtr->nextPtr;
-	if (statePtr->inQueueHead == NULL) {
-	    statePtr->inQueueTail = NULL;
-	}
-	RecycleBuffer(statePtr, bufPtr, 0);
-    }
-
-    /*
-     * Return the number of characters copied into the result buffer. This may
-     * be different from the number of bytes consumed, because of EOL
-     * translations.
-     */
 
-    return copied;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * CopyBuffer --
- *
- *	Copy at most one buffer of input to the result space.
- *
- * Results:
- *	Number of bytes stored in the result buffer. May return zero if no
- *	input is available.
- *
- * Side effects:
- *	Consumes buffered input. May deallocate one buffer.
- *
- *----------------------------------------------------------------------
- */
+	    /*
+	     * 1) We're @EOF because we saw eof char.
+	     */
 
-static int
-CopyBuffer(
-    Channel *chanPtr,		/* Channel from which to read input. */
-    char *result,		/* Where to store the copied input. */
-    int space)			/* How many bytes are available in result to
-				 * store the copied input? */
-{
-    ChannelBuffer *bufPtr;	/* The buffer from which to copy bytes. */
-    int bytesInBuffer;		/* How many bytes are available to be copied
-				 * in the current input buffer? */
-    int copied;			/* How many characters were already copied
-				 * into the destination space? */
+	    if (statePtr->inEofChar
+		    && RemovePoint(bufPtr)[0] == statePtr->inEofChar) {
+		UpdateInterest(chanPtr);
+		break;
+	    }
 
-    /*
-     * If there is no input at all, return zero. The invariant is that either
-     * there is no buffer in the queue, or if the first buffer is empty, it is
-     * also the last buffer (and thus there is no input in the queue). Note
-     * also that if the buffer is empty, we don't leave it in the queue, but
-     * recycle it.
-     */
+	    /*
+	     * 2) The buffer holds a \r while in CRLF translation,
+	     *    followed by the end of the buffer.
+	     */
 
-    if (chanPtr->inQueueHead == NULL) {
-	return 0;
-    }
-    bufPtr = chanPtr->inQueueHead;
-    bytesInBuffer = BytesLeft(bufPtr);
+	    assert(statePtr->inputTranslation == TCL_TRANSLATE_CRLF);
+	    assert(RemovePoint(bufPtr)[0] == '\r');
+	    assert(BytesLeft(bufPtr) == 1);
 
-    copied = 0;
+	    if (bufPtr->nextPtr == NULL) {
+		/* There's no more buffered data.... */
 
-    if (bytesInBuffer == 0) {
-	RecycleBuffer(chanPtr->state, bufPtr, 0);
-	chanPtr->inQueueHead = NULL;
-	chanPtr->inQueueTail = NULL;
-	return 0;
-    }
+		if (statePtr->flags & CHANNEL_EOF) {
+		    /* ...and there never will be. */
 
-    /*
-     * Copy the current chunk into the result buffer.
-     */
+		    *p++ = '\r';
+		    bytesToRead--;
+		    bufPtr->nextRemoved++;
+		} else if (statePtr->flags & CHANNEL_BLOCKED) {
+		    /* ...and we cannot get more now. */
+		    SetFlag(statePtr, CHANNEL_NEED_MORE_DATA);
+		    UpdateInterest(chanPtr);
+		    break;
+		} else {
+		    /* ... so we need to get some. */
+		    goto moreData;
+		}
+	    }
 
-    if (bytesInBuffer < space) {
-	space = bytesInBuffer;
-    }
+	    if (bufPtr->nextPtr) {
+		/* There's a next buffer.  Shift orphan \r to it. */
 
-    memcpy(result, RemovePoint(bufPtr), (size_t) space);
-    bufPtr->nextRemoved += space;
-    copied = space;
+		ChannelBuffer *nextPtr = bufPtr->nextPtr;
 
-    /*
-     * We don't care about in-stream EOF characters here as the data read here
-     * may still flow through one or more transformations, i.e. is not in its
-     * final state yet.
-     */
+		nextPtr->nextRemoved -= 1;
+		RemovePoint(nextPtr)[0] = '\r';
+		bufPtr->nextRemoved++;
+	    }
+	}
 
-    /*
-     * If the current buffer is empty recycle it.
-     */
+	if (IsBufferEmpty(bufPtr)) {
+	    statePtr->inQueueHead = bufPtr->nextPtr;
+	    if (statePtr->inQueueHead == NULL) {
+		statePtr->inQueueTail = NULL;
+	    }
+	    RecycleBuffer(statePtr, bufPtr, 0);
+	}
 
-    if (IsBufferEmpty(bufPtr)) {
-	chanPtr->inQueueHead = bufPtr->nextPtr;
-	if (chanPtr->inQueueHead == NULL) {
-	    chanPtr->inQueueTail = NULL;
+	if ((GotFlag(statePtr, CHANNEL_NONBLOCKING) || allowShortReads)
+		&& GotFlag(statePtr, CHANNEL_BLOCKED)) {
+	    break;
 	}
-	RecycleBuffer(chanPtr->state, bufPtr, 0);
+    }
+    if (bytesToRead == 0) {
+	ResetFlag(statePtr, CHANNEL_BLOCKED);
     }
 
-    /*
-     * Return the number of characters copied into the result buffer.
-     */
-
-    return copied;
+    Tcl_Release(chanPtr);
+    return (int)(p - dst);
 }
 
 /*
@@ -9682,12 +9480,15 @@ StackSetBlockMode(
 {
     int result = 0;
     Tcl_DriverBlockModeProc *blockModeProc;
+    ChannelState *statePtr = chanPtr->state;
 
     /*
      * Start at the top of the channel stack
+     * TODO: Examine what can go wrong when blockModeProc calls
+     * disturb the stacking state of the channel.
      */
 
-    chanPtr = chanPtr->state->topChanPtr;
+    chanPtr = statePtr->topChanPtr;
     while (chanPtr != NULL) {
 	blockModeProc = Tcl_ChannelBlockModeProc(chanPtr->typePtr);
 	if (blockModeProc != NULL) {
@@ -10826,6 +10627,7 @@ SetChannelFromAny(
     }
     if (objPtr->typePtr == &chanObjType) {
 	/*
+	 * TODO: TAINT Flag and dup'd channel values?
 	 * The channel is valid until any call to DetachChannel occurs.
 	 * Ensure consistency checks are done.
 	 */
@@ -10902,20 +10704,14 @@ DumpFlags(
     ChanFlag('n', CHANNEL_NONBLOCKING);
     ChanFlag('l', CHANNEL_LINEBUFFERED);
     ChanFlag('u', CHANNEL_UNBUFFERED);
-    ChanFlag('R', BUFFER_READY);
     ChanFlag('F', BG_FLUSH_SCHEDULED);
     ChanFlag('c', CHANNEL_CLOSED);
     ChanFlag('E', CHANNEL_EOF);
     ChanFlag('S', CHANNEL_STICKY_EOF);
     ChanFlag('B', CHANNEL_BLOCKED);
     ChanFlag('/', INPUT_SAW_CR);
-    ChanFlag('*', INPUT_NEED_NL);
     ChanFlag('D', CHANNEL_DEAD);
     ChanFlag('R', CHANNEL_RAW_MODE);
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-    ChanFlag('T', CHANNEL_TIMER_FEV);
-    ChanFlag('H', CHANNEL_HAS_MORE_DATA);
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
     ChanFlag('x', CHANNEL_INCLOSE);
 
     buf[i] ='\0';
diff --git a/generic/tclIO.h b/generic/tclIO.h
index e84f300..097cd61 100644
--- a/generic/tclIO.h
+++ b/generic/tclIO.h
@@ -36,6 +36,7 @@
  */
 
 typedef struct ChannelBuffer {
+    int refCount;		/* Current uses count */
     int nextAdded;		/* The next position into which a character
 				 * will be put in the buffer. */
     int nextRemoved;		/* Position of next byte to be removed from
@@ -226,11 +227,6 @@ typedef struct ChannelState {
 					 * flushed after every newline. */
 #define CHANNEL_UNBUFFERED	(1<<5)	/* Output to the channel must always
 					 * be flushed immediately. */
-#define BUFFER_READY		(1<<6)	/* Current output buffer (the
-					 * curOutPtr field in the channel
-					 * structure) should be output as soon
-					 * as possible even though it may not
-					 * be full. */
 #define BG_FLUSH_SCHEDULED	(1<<7)	/* A background flush of the queued
 					 * output buffers has been
 					 * scheduled. */
@@ -252,9 +248,6 @@ typedef struct ChannelState {
 #define INPUT_SAW_CR		(1<<12)	/* Channel is in CRLF eol input
 					 * translation mode and the last byte
 					 * seen was a "\r". */
-#define INPUT_NEED_NL		(1<<15)	/* Saw a '\r' at end of last buffer,
-					 * and there should be a '\n' at
-					 * beginning of next buffer. */
 #define CHANNEL_DEAD		(1<<13)	/* The channel has been closed by the
 					 * exit handler (on exit) but not
 					 * deallocated. When any IO operation
@@ -274,29 +267,6 @@ typedef struct ChannelState {
 					 * changes. */
 #define CHANNEL_RAW_MODE	(1<<16)	/* When set, notes that the Raw API is
 					 * being used. */
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-#define CHANNEL_TIMER_FEV	(1<<17)	/* When set the event we are notified
-					 * by is a fileevent generated by a
-					 * timer. We don't know if the driver
-					 * has more data and should not try to
-					 * read from it. If the system needs
-					 * more than is in the buffers out
-					 * read routines will simulate a short
-					 * read (0 characters read) */
-#define CHANNEL_HAS_MORE_DATA   (1<<18) /* Set by NotifyChannel for a channel
-					 * if and only if the channel is
-					 * configured non-blocking, the driver
-					 * for said channel has no
-					 * blockmodeproc, and data has arrived
-					 * for reading at the OS level). A
-					 * GetInput will pass reading from the
-					 * driver if the channel is
-					 * non-blocking, without blockmode
-					 * proc and the flag has not been set.
-					 * A read will be performed if the
-					 * flag is set. This will reset the
-					 * flag as well. */
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
 
 #define CHANNEL_INCLOSE		(1<<19)	/* Channel is currently being closed.
 					 * Its structures are still live and
diff --git a/generic/tclIOCmd.c b/generic/tclIOCmd.c
index 1673bce..3368a76 100644
--- a/generic/tclIOCmd.c
+++ b/generic/tclIOCmd.c
@@ -181,6 +181,7 @@ Tcl_PutsObjCmd(
 	return TCL_ERROR;
     }
 
+    Tcl_Preserve(chan);
     result = Tcl_WriteObj(chan, string);
     if (result < 0) {
 	goto error;
@@ -191,6 +192,7 @@ Tcl_PutsObjCmd(
 	    goto error;
 	}
     }
+    Tcl_Release(chan);
     return TCL_OK;
 
     /*
@@ -205,6 +207,7 @@ Tcl_PutsObjCmd(
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf("error writing \"%s\": %s",
 		TclGetString(chanObjPtr), Tcl_PosixError(interp)));
     }
+    Tcl_Release(chan);
     return TCL_ERROR;
 }
 
@@ -252,6 +255,7 @@ Tcl_FlushObjCmd(
 	return TCL_ERROR;
     }
 
+    Tcl_Preserve(chan);
     if (Tcl_Flush(chan) != TCL_OK) {
 	/*
 	 * TIP #219.
@@ -265,8 +269,10 @@ Tcl_FlushObjCmd(
 		    "error flushing \"%s\": %s",
 		    TclGetString(chanObjPtr), Tcl_PosixError(interp)));
 	}
+	Tcl_Release(chan);
 	return TCL_ERROR;
     }
+    Tcl_Release(chan);
     return TCL_OK;
 }
 
@@ -299,6 +305,7 @@ Tcl_GetsObjCmd(
     int lineLen;		/* Length of line just read. */
     int mode;			/* Mode in which channel is opened. */
     Tcl_Obj *linePtr, *chanObjPtr;
+    int code = TCL_OK;
 
     if ((objc != 2) && (objc != 3)) {
 	Tcl_WrongNumArgs(interp, 1, objv, "channelId ?varName?");
@@ -315,6 +322,7 @@ Tcl_GetsObjCmd(
 	return TCL_ERROR;
     }
 
+    Tcl_Preserve(chan);
     linePtr = Tcl_NewObj();
     lineLen = Tcl_GetsObj(chan, linePtr);
     if (lineLen < 0) {
@@ -333,20 +341,24 @@ Tcl_GetsObjCmd(
 			"error reading \"%s\": %s",
 			TclGetString(chanObjPtr), Tcl_PosixError(interp)));
 	    }
-	    return TCL_ERROR;
+	    code = TCL_ERROR;
+	    goto done;
 	}
 	lineLen = -1;
     }
     if (objc == 3) {
 	if (Tcl_ObjSetVar2(interp, objv[2], NULL, linePtr,
 		TCL_LEAVE_ERR_MSG) == NULL) {
-	    return TCL_ERROR;
+	    code = TCL_ERROR;
+	    goto done;
 	}
 	Tcl_SetObjResult(interp, Tcl_NewIntObj(lineLen));
     } else {
 	Tcl_SetObjResult(interp, linePtr);
     }
-    return TCL_OK;
+  done:
+    Tcl_Release(chan);
+    return code;
 }
 
 /*
@@ -453,6 +465,7 @@ Tcl_ReadObjCmd(
 
     resultPtr = Tcl_NewObj();
     Tcl_IncrRefCount(resultPtr);
+    Tcl_Preserve(chan);
     charactersRead = Tcl_ReadChars(chan, resultPtr, toRead, 0);
     if (charactersRead < 0) {
 	/*
@@ -467,6 +480,7 @@ Tcl_ReadObjCmd(
 		    "error reading \"%s\": %s",
 		    TclGetString(chanObjPtr), Tcl_PosixError(interp)));
 	}
+	Tcl_Release(chan);
 	Tcl_DecrRefCount(resultPtr);
 	return TCL_ERROR;
     }
@@ -485,6 +499,7 @@ Tcl_ReadObjCmd(
 	}
     }
     Tcl_SetObjResult(interp, resultPtr);
+    Tcl_Release(chan);
     Tcl_DecrRefCount(resultPtr);
     return TCL_OK;
 }
@@ -544,6 +559,7 @@ Tcl_SeekObjCmd(
 	mode = modeArray[optionIndex];
     }
 
+    Tcl_Preserve(chan);
     result = Tcl_Seek(chan, offset, mode);
     if (result == Tcl_LongAsWide(-1)) {
 	/*
@@ -558,8 +574,10 @@ Tcl_SeekObjCmd(
 		    "error during seek on \"%s\": %s",
 		    TclGetString(objv[1]), Tcl_PosixError(interp)));
 	}
+	Tcl_Release(chan);
 	return TCL_ERROR;
     }
+    Tcl_Release(chan);
     return TCL_OK;
 }
 
@@ -590,6 +608,7 @@ Tcl_TellObjCmd(
 {
     Tcl_Channel chan;		/* The channel to tell on. */
     Tcl_WideInt newLoc;
+    int code;
 
     if (objc != 2) {
 	Tcl_WrongNumArgs(interp, 1, objv, "channelId");
@@ -605,6 +624,7 @@ Tcl_TellObjCmd(
 	return TCL_ERROR;
     }
 
+    Tcl_Preserve(chan);
     newLoc = Tcl_Tell(chan);
 
     /*
@@ -613,7 +633,10 @@ Tcl_TellObjCmd(
      * them into the regular interpreter result.
      */
 
-    if (TclChanCaughtErrorBypass(interp, chan)) {
+
+    code  = TclChanCaughtErrorBypass(interp, chan);
+    Tcl_Release(chan);
+    if (code) {
 	return TCL_ERROR;
     }
 
@@ -896,7 +919,7 @@ Tcl_ExecObjCmd(
 	if (string[0] != '-') {
 	    break;
 	}
-	if (Tcl_GetIndexFromObj(interp, objv[skip], options, "switch",
+	if (Tcl_GetIndexFromObj(interp, objv[skip], options, "option",
 		TCL_EXACT, &index) != TCL_OK) {
 	    return TCL_ERROR;
 	}
@@ -910,7 +933,7 @@ Tcl_ExecObjCmd(
 	}
     }
     if (objc <= skip) {
-	Tcl_WrongNumArgs(interp, 1, objv, "?-switch ...? arg ?arg ...?");
+	Tcl_WrongNumArgs(interp, 1, objv, "?-option ...? arg ?arg ...?");
 	return TCL_ERROR;
     }
 
@@ -1673,7 +1696,7 @@ Tcl_FcopyObjCmd(
     toRead = -1;
     cmdPtr = NULL;
     for (i = 3; i < objc; i += 2) {
-	if (Tcl_GetIndexFromObj(interp, objv[i], switches, "switch", 0,
+	if (Tcl_GetIndexFromObj(interp, objv[i], switches, "option", 0,
 		&index) != TCL_OK) {
 	    return TCL_ERROR;
 	}
diff --git a/generic/tclIOGT.c b/generic/tclIOGT.c
index 825f408..9c4347d 100644
--- a/generic/tclIOGT.c
+++ b/generic/tclIOGT.c
@@ -210,7 +210,27 @@ struct TransformChannelData {
 				 * a transformation of incoming data. Also
 				 * serves as buffer of all data not yet
 				 * consumed by the reader. */
+    int refCount;
 };
+
+static void
+PreserveData(
+    TransformChannelData *dataPtr)
+{
+    dataPtr->refCount++;
+}
+
+static void
+ReleaseData(
+    TransformChannelData *dataPtr)
+{
+    if (--dataPtr->refCount) {
+	return;
+    }
+    ResultClear(&dataPtr->result);
+    Tcl_DecrRefCount(dataPtr->command);
+    ckfree(dataPtr);
+}
 
 /*
  *----------------------------------------------------------------------
@@ -240,6 +260,7 @@ TclChannelTransform(
     Channel *chanPtr;		/* The actual channel. */
     ChannelState *statePtr;	/* State info for channel. */
     int mode;			/* Read/write mode of the channel. */
+    int objc;
     TransformChannelData *dataPtr;
     Tcl_DString ds;
 
@@ -247,6 +268,12 @@ TclChannelTransform(
 	return TCL_ERROR;
     }
 
+    if (TCL_OK != Tcl_ListObjLength(interp, cmdObjPtr, &objc)) {
+	Tcl_SetObjResult(interp,
+		Tcl_NewStringObj("-command value is not a list", -1));
+	return TCL_ERROR;
+    }
+
     chanPtr = (Channel *) chan;
     statePtr = chanPtr->state;
     chanPtr = statePtr->topChanPtr;
@@ -261,6 +288,7 @@ TclChannelTransform(
 
     dataPtr = ckalloc(sizeof(TransformChannelData));
 
+    dataPtr->refCount = 1;
     Tcl_DStringInit(&ds);
     Tcl_GetChannelOption(interp, chan, "-blocking", &ds);
     dataPtr->readIsFlushed = 0;
@@ -270,7 +298,6 @@ TclChannelTransform(
     }
     Tcl_DStringFree(&ds);
 
-    dataPtr->self = chan;
     dataPtr->watchMask = 0;
     dataPtr->mode = mode;
     dataPtr->timer = NULL;
@@ -286,19 +313,20 @@ TclChannelTransform(
     if (dataPtr->self == NULL) {
 	Tcl_AppendPrintfToObj(Tcl_GetObjResult(interp),
 		"\nfailed to stack channel \"%s\"", Tcl_GetChannelName(chan));
-	Tcl_DecrRefCount(dataPtr->command);
-	ResultClear(&dataPtr->result);
-	ckfree(dataPtr);
+	ReleaseData(dataPtr);
 	return TCL_ERROR;
     }
+    Tcl_Preserve(dataPtr->self);
 
     /*
      * At last initialize the transformation at the script level.
      */
 
+    PreserveData(dataPtr);
     if ((dataPtr->mode & TCL_WRITABLE) && ExecuteCallback(dataPtr, NULL,
 	    A_CREATE_WRITE, NULL, 0, TRANSMIT_DONT, P_NO_PRESERVE) != TCL_OK){
 	Tcl_UnstackChannel(interp, chan);
+	ReleaseData(dataPtr);
 	return TCL_ERROR;
     }
 
@@ -307,9 +335,11 @@ TclChannelTransform(
 	ExecuteCallback(dataPtr, NULL, A_DELETE_WRITE, NULL, 0, TRANSMIT_DONT,
 		P_NO_PRESERVE);
 	Tcl_UnstackChannel(interp, chan);
+	ReleaseData(dataPtr);
 	return TCL_ERROR;
     }
 
+    ReleaseData(dataPtr);
     return TCL_OK;
 }
 
@@ -350,7 +380,10 @@ ExecuteCallback(
     unsigned char *resBuf;
     Tcl_InterpState state = NULL;
     int res = TCL_OK;
-    Tcl_Obj *command = Tcl_DuplicateObj(dataPtr->command);
+    Tcl_Obj *command = TclListObjCopy(NULL, dataPtr->command);
+    Tcl_Interp *eval = dataPtr->interp;
+
+    Tcl_Preserve(eval);
 
     /*
      * Step 1, create the complete command to execute. Do this by appending
@@ -361,26 +394,18 @@ ExecuteCallback(
      */
 
     if (preserve == P_PRESERVE) {
-	state = Tcl_SaveInterpState(dataPtr->interp, res);
+	state = Tcl_SaveInterpState(eval, res);
     }
 
     Tcl_IncrRefCount(command);
-    res = Tcl_ListObjAppendElement(dataPtr->interp, command,
-	    Tcl_NewStringObj((char *) op, -1));
-    if (res != TCL_OK) {
-	goto cleanup;
-    }
+    Tcl_ListObjAppendElement(NULL, command, Tcl_NewStringObj((char *) op, -1));
 
     /*
      * Use a byte-array to prevent the misinterpretation of binary data coming
      * through as UTF while at the tcl level.
      */
 
-    res = Tcl_ListObjAppendElement(dataPtr->interp, command,
-	    Tcl_NewByteArrayObj(buf, bufLen));
-    if (res != TCL_OK) {
-	goto cleanup;
-    }
+    Tcl_ListObjAppendElement(NULL, command, Tcl_NewByteArrayObj(buf, bufLen));
 
     /*
      * Step 2, execute the command at the global level of the interpreter used
@@ -390,13 +415,14 @@ ExecuteCallback(
      * current interpreter. Don't copy if in preservation mode.
      */
 
-    res = Tcl_EvalObjEx(dataPtr->interp, command, TCL_EVAL_GLOBAL);
+    res = Tcl_EvalObjEx(eval, command, TCL_EVAL_GLOBAL);
     Tcl_DecrRefCount(command);
     command = NULL;
 
-    if ((res != TCL_OK) && (interp != NULL) && (dataPtr->interp != interp)
+    if ((res != TCL_OK) && (interp != NULL) && (eval != interp)
 	    && (preserve == P_NO_PRESERVE)) {
-	Tcl_SetObjResult(interp, Tcl_GetObjResult(dataPtr->interp));
+	Tcl_SetObjResult(interp, Tcl_GetObjResult(eval));
+	Tcl_Release(eval);
 	return res;
     }
 
@@ -411,20 +437,26 @@ ExecuteCallback(
 	break;
 
     case TRANSMIT_DOWN:
-	resObj = Tcl_GetObjResult(dataPtr->interp);
+	if (dataPtr->self == NULL) {
+	    break;
+	}
+	resObj = Tcl_GetObjResult(eval);
 	resBuf = Tcl_GetByteArrayFromObj(resObj, &resLen);
 	Tcl_WriteRaw(Tcl_GetStackedChannel(dataPtr->self), (char *) resBuf,
 		resLen);
 	break;
 
     case TRANSMIT_SELF:
-	resObj = Tcl_GetObjResult(dataPtr->interp);
+	if (dataPtr->self == NULL) {
+	    break;
+	}
+	resObj = Tcl_GetObjResult(eval);
 	resBuf = Tcl_GetByteArrayFromObj(resObj, &resLen);
 	Tcl_WriteRaw(dataPtr->self, (char *) resBuf, resLen);
 	break;
 
     case TRANSMIT_IBUF:
-	resObj = Tcl_GetObjResult(dataPtr->interp);
+	resObj = Tcl_GetObjResult(eval);
 	resBuf = Tcl_GetByteArrayFromObj(resObj, &resLen);
 	ResultAdd(&dataPtr->result, resBuf, resLen);
 	break;
@@ -434,24 +466,16 @@ ExecuteCallback(
 	 * Interpret result as integer number.
 	 */
 
-	resObj = Tcl_GetObjResult(dataPtr->interp);
-	TclGetIntFromObj(dataPtr->interp, resObj, &dataPtr->maxRead);
+	resObj = Tcl_GetObjResult(eval);
+	TclGetIntFromObj(eval, resObj, &dataPtr->maxRead);
 	break;
     }
 
-    Tcl_ResetResult(dataPtr->interp);
+    Tcl_ResetResult(eval);
     if (preserve == P_PRESERVE) {
-	(void) Tcl_RestoreInterpState(dataPtr->interp, state);
-    }
-    return res;
-
-  cleanup:
-    if (preserve == P_PRESERVE) {
-	(void) Tcl_RestoreInterpState(dataPtr->interp, state);
-    }
-    if (command != NULL) {
-	Tcl_DecrRefCount(command);
+	(void) Tcl_RestoreInterpState(eval, state);
     }
+    Tcl_Release(eval);
     return res;
 }
 
@@ -535,6 +559,7 @@ TransformCloseProc(
      * system rely on (f.e. signaling the close to interested parties).
      */
 
+    PreserveData(dataPtr);
     if (dataPtr->mode & TCL_WRITABLE) {
 	ExecuteCallback(dataPtr, interp, A_FLUSH_WRITE, NULL, 0,
 		TRANSMIT_DOWN, P_PRESERVE);
@@ -554,14 +579,15 @@ TransformCloseProc(
 	ExecuteCallback(dataPtr, interp, A_DELETE_READ, NULL, 0,
 		TRANSMIT_DONT, P_PRESERVE);
     }
+    ReleaseData(dataPtr);
 
     /*
      * General cleanup.
      */
 
-    ResultClear(&dataPtr->result);
-    Tcl_DecrRefCount(dataPtr->command);
-    ckfree(dataPtr);
+    Tcl_Release(dataPtr->self);
+    dataPtr->self = NULL;
+    ReleaseData(dataPtr);
     return TCL_OK;
 }
 
@@ -596,7 +622,7 @@ TransformInputProc(
      * Should assert(dataPtr->mode & TCL_READABLE);
      */
 
-    if (toRead == 0) {
+    if (toRead == 0 || dataPtr->self == NULL) {
 	/*
 	 * Catch a no-op.
 	 */
@@ -606,6 +632,7 @@ TransformInputProc(
     gotBytes = 0;
     downChan = Tcl_GetStackedChannel(dataPtr->self);
 
+    PreserveData(dataPtr);
     while (toRead > 0) {
 	/*
 	 * Loop until the request is satisfied (or no data is available from
@@ -623,7 +650,7 @@ TransformInputProc(
 	     * break out of the loop and return to the caller.
 	     */
 
-	    return gotBytes;
+	    break;
 	}
 
 	/*
@@ -647,7 +674,7 @@ TransformInputProc(
 	    }
 	} /* else: 'maxRead < 0' == Accept the current value of toRead. */
 	if (toRead <= 0) {
-	    return gotBytes;
+	    break;
 	}
 
 	/*
@@ -656,44 +683,40 @@ TransformInputProc(
 
 	read = Tcl_ReadRaw(downChan, buf, toRead);
 	if (read < 0) {
-	    /*
-	     * Report errors to caller. EAGAIN is a special situation. If we
-	     * had some data before we report that instead of the request to
-	     * re-try.
-	     */
-		int error = Tcl_GetErrno();
+	    if (Tcl_InputBlocked(downChan) && (gotBytes > 0)) {
+		/*
+		 * Zero bytes available from downChan because blocked.
+		 * But nonzero bytes already copied, so total is a
+		 * valid blocked short read. Return to caller.
+		 */
 
-	    if ((error == EAGAIN) && (gotBytes > 0)) {
-		return gotBytes;
+		break;
 	    }
 
-	    *errorCodePtr = error;
-	    return -1;
-	} else if (read == 0) {
 	    /*
-	     * Check wether we hit on EOF in the underlying channel or not. If
-	     * not differentiate between blocking and non-blocking modes. In
-	     * non-blocking mode we ran temporarily out of data. Signal this
-	     * to the caller via EWOULDBLOCK and error return (-1). In the
-	     * other cases we simply return what we got and let the caller
-	     * wait for more. On the other hand, if we got an EOF we have to
-	     * convert and flush all waiting partial data.
+	     * Either downChan is not blocked (there's a real error).
+	     * or it is and there are no bytes copied yet.  In either
+	     * case we want to pass the "error" along to the caller,
+	     * either to report an error, or to signal to the caller
+	     * that zero bytes are available because blocked.
 	     */
 
-	    if (!Tcl_Eof(downChan)) {
-		if ((gotBytes == 0) && (dataPtr->flags & CHANNEL_ASYNC)) {
-		    *errorCodePtr = EWOULDBLOCK;
-		    return -1;
-		}
-		return gotBytes;
-	    }
+	    *errorCodePtr = Tcl_GetErrno();
+	    gotBytes = -1;
+	    break;
+	} else if (read == 0) {
+
+	    /*
+	     * Zero returned from Tcl_ReadRaw() always indicates EOF
+	     * on the down channel.
+	     */
 
 	    if (dataPtr->readIsFlushed) {
 		/*
 		 * Already flushed, nothing to do anymore.
 		 */
 
-		return gotBytes;
+		break;
 	    }
 
 	    dataPtr->readIsFlushed = 1;
@@ -705,7 +728,7 @@ TransformInputProc(
 		 * We had nothing to flush.
 		 */
 
-		return gotBytes;
+		break;
 	    }
 
 	    continue;		/* at: while (toRead > 0) */
@@ -719,9 +742,11 @@ TransformInputProc(
 	if (ExecuteCallback(dataPtr, NULL, A_READ, UCHARP(buf), read,
 		TRANSMIT_IBUF, P_PRESERVE) != TCL_OK) {
 	    *errorCodePtr = EINVAL;
-	    return -1;
+	    gotBytes = -1;
+	    break;
 	}
     } /* while toRead > 0 */
+    ReleaseData(dataPtr);
 
     return gotBytes;
 }
@@ -763,11 +788,13 @@ TransformOutputProc(
 	return 0;
     }
 
+    PreserveData(dataPtr);
     if (ExecuteCallback(dataPtr, NULL, A_WRITE, UCHARP(buf), toWrite,
 	    TRANSMIT_DOWN, P_NO_PRESERVE) != TCL_OK) {
 	*errorCodePtr = EINVAL;
-	return -1;
+	toWrite = -1;
     }
+    ReleaseData(dataPtr);
 
     return toWrite;
 }
@@ -820,6 +847,7 @@ TransformSeekProc(
      * request down, unchanged.
      */
 
+    PreserveData(dataPtr);
     if (dataPtr->mode & TCL_WRITABLE) {
 	ExecuteCallback(dataPtr, NULL, A_FLUSH_WRITE, NULL, 0, TRANSMIT_DOWN,
 		P_NO_PRESERVE);
@@ -831,6 +859,7 @@ TransformSeekProc(
 	ResultClear(&dataPtr->result);
 	dataPtr->readIsFlushed = 0;
     }
+    ReleaseData(dataPtr);
 
     return parentSeekProc(Tcl_GetChannelInstanceData(parent), offset, mode,
 	    errorCodePtr);
@@ -891,6 +920,7 @@ TransformWideSeekProc(
      * request down, unchanged.
      */
 
+    PreserveData(dataPtr);
     if (dataPtr->mode & TCL_WRITABLE) {
 	ExecuteCallback(dataPtr, NULL, A_FLUSH_WRITE, NULL, 0, TRANSMIT_DOWN,
 		P_NO_PRESERVE);
@@ -902,6 +932,7 @@ TransformWideSeekProc(
 	ResultClear(&dataPtr->result);
 	dataPtr->readIsFlushed = 0;
     }
+    ReleaseData(dataPtr);
 
     /*
      * If we have a wide seek capability, we should stick with that.
@@ -1056,6 +1087,9 @@ TransformWatchProc(
      * unchanged.
      */
 
+    if (dataPtr->self == NULL) {
+	return;
+    }
     downChan = Tcl_GetStackedChannel(dataPtr->self);
 
     Tcl_GetChannelType(downChan)->watchProc(
diff --git a/generic/tclIORChan.c b/generic/tclIORChan.c
index cb0282a..ff602c6 100644
--- a/generic/tclIORChan.c
+++ b/generic/tclIORChan.c
@@ -99,31 +99,9 @@ typedef struct {
     Tcl_ThreadId thread;	/* Thread the 'interp' belongs to. == Handler thread */
     Tcl_ThreadId owner;         /* Thread owning the structure.    == Channel thread */
 #endif
-
-    /* See [==] as well.
-     * Storage for the command prefix and the additional words required for
-     * the invocation of methods in the command handler.
-     *
-     * argv [0] ... [.] | [argc-2] [argc-1] | [argc]  [argc+2]
-     *      cmd ... pfx | method   chan     | detail1 detail2
-     *      ~~~~ CT ~~~            ~~ CT ~~
-     *
-     * CT = Belongs to the 'Command handler Thread'.
-     */
-
-    int argc;			/* Number of preallocated words - 2 */
-    Tcl_Obj **argv;		/* Preallocated array for calling the handler.
-				 * args[0] is placeholder for cmd word.
-				 * Followed by the arguments in the prefix,
-				 * plus 4 placeholders for method, channel,
-				 * and at most two varying (method specific)
-				 * words. */
-    int methods;		/* Bitmask of supported methods */
-
-    /*
-     * NOTE (9): Should we have predefined shared literals for the method
-     * names?
-     */
+    Tcl_Obj *cmd;		/* Callback command prefix */
+    Tcl_Obj *methods;		/* Methods to append to command prefix */
+    Tcl_Obj *name;		/* Name of the channel as created */
 
     int mode;			/* Mask of R/W mode */
     int interest;		/* Mask of events the channel is interested
@@ -450,9 +428,8 @@ static ReflectedChannel * NewReflectedChannel(Tcl_Interp *interp,
 			    Tcl_Obj *cmdpfxObj, int mode, Tcl_Obj *handleObj);
 static Tcl_Obj *	NextHandle(void);
 static void		FreeReflectedChannel(ReflectedChannel *rcPtr);
-static void		FreeReflectedChannelArgs(ReflectedChannel *rcPtr);
 static int		InvokeTclMethod(ReflectedChannel *rcPtr,
-			    const char *method, Tcl_Obj *argOneObj,
+			    MethodName method, Tcl_Obj *argOneObj,
 			    Tcl_Obj *argTwoObj, Tcl_Obj **resultObjPtr);
 
 static ReflectedChannelMap *	GetReflectedChannelMap(Tcl_Interp *interp);
@@ -467,16 +444,14 @@ static int		ErrnoReturn(ReflectedChannel *rcPtr, Tcl_Obj *resObj);
  * list-quoting to keep the words of the message together. See also [x].
  */
 
-static const char *msg_read_unsup = "{read not supported by Tcl driver}";
 static const char *msg_read_toomuch = "{read delivered more than requested}";
-static const char *msg_write_unsup = "{write not supported by Tcl driver}";
 static const char *msg_write_toomuch = "{write wrote more than requested}";
 static const char *msg_write_nothing = "{write wrote nothing}";
 static const char *msg_seek_beforestart = "{Tried to seek before origin}";
 #ifdef TCL_THREADS
 static const char *msg_send_originlost = "{Channel thread lost}";
-static const char *msg_send_dstlost    = "{Owner lost}";
 #endif /* TCL_THREADS */
+static const char *msg_send_dstlost    = "{Owner lost}";
 static const char *msg_dstlost    = "-code 1 -level 0 -errorcode NONE -errorinfo {} -errorline 1 {Owner lost}";
 
 /*
@@ -583,10 +558,6 @@ TclChanCreateObjCmd(
 
     rcId = NextHandle();
     rcPtr = NewReflectedChannel(interp, cmdObj, mode, rcId);
-    chan = Tcl_CreateChannel(&tclRChannelType, TclGetString(rcId), rcPtr,
-	    mode);
-    rcPtr->chan = chan;
-    chanPtr = (Channel *) chan;
 
     /*
      * Invoke 'initialize' and validate that the handler is present and ok.
@@ -600,7 +571,7 @@ TclChanCreateObjCmd(
 
     modeObj = DecodeEventMask(mode);
     /* assert modeObj.refCount == 1 */
-    result = InvokeTclMethod(rcPtr, "initialize", modeObj, NULL, &resObj);
+    result = InvokeTclMethod(rcPtr, METH_INIT, modeObj, NULL, &resObj);
     Tcl_DecrRefCount(modeObj);
 
     if (result != TCL_OK) {
@@ -683,7 +654,11 @@ TclChanCreateObjCmd(
      * Everything is fine now.
      */
 
-    rcPtr->methods = methods;
+    chan = Tcl_CreateChannel(&tclRChannelType, TclGetString(rcId), rcPtr,
+	    mode);
+    rcPtr->chan = chan;
+    Tcl_Preserve(chan);
+    chanPtr = (Channel *) chan;
 
     if ((methods & NULLABLE_METHODS) != NULLABLE_METHODS) {
 	/*
@@ -744,12 +719,10 @@ TclChanCreateObjCmd(
     return TCL_OK;
 
   error:
-    /*
-     * Signal to ReflectClose to not call 'finalize'.
-     */
-
-    rcPtr->methods = 0;
-    Tcl_Close(interp, chan);
+    Tcl_DecrRefCount(rcPtr->name);
+    Tcl_DecrRefCount(rcPtr->methods);
+    Tcl_DecrRefCount(rcPtr->cmd);
+    ckfree((char*) rcPtr);
     return TCL_ERROR;
 
 #undef MODE
@@ -1138,6 +1111,7 @@ ReflectClose(
     ReflectedChannelMap *rcmPtr;/* Map of reflected channels with handlers in
 				 * this interp */
     Tcl_HashEntry *hPtr;	/* Entry in the above map */
+    const Tcl_ChannelType *tctPtr;
 
     if (TclInThreadExit()) {
 	/*
@@ -1172,21 +1146,15 @@ ReflectClose(
 	    if (result != TCL_OK) {
 		FreeReceivedError(&p);
 	    }
+	    return EOK;
 	}
 #endif
 
-        Tcl_EventuallyFree(rcPtr, (Tcl_FreeProc *) FreeReflectedChannel);
-	return EOK;
-    }
-
-    /*
-     * -- No -- ASSERT rcPtr->methods & FLAG(METH_FINAL)
-     *
-     * A cleaned method mask here implies that the channel creation was
-     * aborted, and "finalize" must not be called.
-     */
-
-    if (rcPtr->methods == 0) {
+	tctPtr = ((Channel *)rcPtr->chan)->typePtr;
+	if (tctPtr && tctPtr != &tclRChannelType) {
+	    ckfree((char *)tctPtr);
+	    ((Channel *)rcPtr->chan)->typePtr = NULL;
+	}
         Tcl_EventuallyFree(rcPtr, (Tcl_FreeProc *) FreeReflectedChannel);
 	return EOK;
     }
@@ -1208,14 +1176,12 @@ ReflectClose(
 
         Tcl_DeleteEvents(ReflectEventDelete, rcPtr);
 
-        Tcl_EventuallyFree(rcPtr, (Tcl_FreeProc *) FreeReflectedChannel);
-
 	if (result != TCL_OK) {
 	    PassReceivedErrorInterp(interp, &p);
 	}
     } else {
 #endif
-	result = InvokeTclMethod(rcPtr, "finalize", NULL, NULL, &resObj);
+	result = InvokeTclMethod(rcPtr, METH_FINAL, NULL, NULL, &resObj);
 	if ((result != TCL_OK) && (interp != NULL)) {
 	    Tcl_SetChannelErrorInterp(interp, resObj);
 	}
@@ -1253,6 +1219,11 @@ ReflectClose(
 	}
 #endif
 
+	tctPtr = ((Channel *)rcPtr->chan)->typePtr;
+	if (tctPtr && tctPtr != &tclRChannelType) {
+	    ckfree((char *)tctPtr);
+	    ((Channel *)rcPtr->chan)->typePtr = NULL;
+	}
         Tcl_EventuallyFree(rcPtr, (Tcl_FreeProc *) FreeReflectedChannel);
 #ifdef TCL_THREADS
     }
@@ -1290,18 +1261,6 @@ ReflectInput(
     Tcl_Obj *resObj;		/* Result data for 'read' */
 
     /*
-     * The following check can be done before thread redirection, because we
-     * are reading from an item which is readonly, i.e. will never change
-     * during the lifetime of the channel.
-     */
-
-    if (!(rcPtr->methods & FLAG(METH_READ))) {
-	SetChannelErrorStr(rcPtr->chan, msg_read_unsup);
-	*errorCodePtr = EINVAL;
-	return -1;
-    }
-
-    /*
      * Are we in the correct thread?
      */
 
@@ -1339,7 +1298,7 @@ ReflectInput(
     toReadObj = Tcl_NewIntObj(toRead);
     Tcl_IncrRefCount(toReadObj);
 
-    if (InvokeTclMethod(rcPtr, "read", toReadObj, NULL, &resObj)!=TCL_OK) {
+    if (InvokeTclMethod(rcPtr, METH_READ, toReadObj, NULL, &resObj)!=TCL_OK) {
 	int code = ErrnoReturn(rcPtr, resObj);
 
 	if (code < 0) {
@@ -1405,18 +1364,6 @@ ReflectOutput(
     int written;
 
     /*
-     * The following check can be done before thread redirection, because we
-     * are reading from an item which is readonly, i.e. will never change
-     * during the lifetime of the channel.
-     */
-
-    if (!(rcPtr->methods & FLAG(METH_WRITE))) {
-	SetChannelErrorStr(rcPtr->chan, msg_write_unsup);
-	*errorCodePtr = EINVAL;
-	return -1;
-    }
-
-    /*
      * Are we in the correct thread?
      */
 
@@ -1450,11 +1397,12 @@ ReflectOutput(
     /* ASSERT: rcPtr->mode & TCL_WRITABLE */
 
     Tcl_Preserve(rcPtr);
+    Tcl_Preserve(rcPtr->interp);
 
     bufObj = Tcl_NewByteArrayObj((unsigned char *) buf, toWrite);
     Tcl_IncrRefCount(bufObj);
 
-    if (InvokeTclMethod(rcPtr, "write", bufObj, NULL, &resObj) != TCL_OK) {
+    if (InvokeTclMethod(rcPtr, METH_WRITE, bufObj, NULL, &resObj) != TCL_OK) {
 	int code = ErrnoReturn(rcPtr, resObj);
 
 	if (code < 0) {
@@ -1466,6 +1414,14 @@ ReflectOutput(
         goto invalid;
     }
 
+    if (Tcl_InterpDeleted(rcPtr->interp)) {
+	/*
+	 * The interp was destroyed during InvokeTclMethod().
+	 */
+
+	SetChannelErrorStr(rcPtr->chan, msg_send_dstlost);
+        goto invalid;
+    }
     if (Tcl_GetIntFromObj(rcPtr->interp, resObj, &written) != TCL_OK) {
 	Tcl_SetChannelError(rcPtr->chan, MarshallError(rcPtr->interp));
         goto invalid;
@@ -1495,6 +1451,7 @@ ReflectOutput(
  stop:
     Tcl_DecrRefCount(bufObj);
     Tcl_DecrRefCount(resObj);		/* Remove reference held from invoke */
+    Tcl_Release(rcPtr->interp);
     Tcl_Release(rcPtr);
     return written;
  invalid:
@@ -1568,7 +1525,7 @@ ReflectSeekWide(
     Tcl_IncrRefCount(offObj);
     Tcl_IncrRefCount(baseObj);
 
-    if (InvokeTclMethod(rcPtr, "seek", offObj, baseObj, &resObj) != TCL_OK) {
+    if (InvokeTclMethod(rcPtr, METH_SEEK, offObj, baseObj, &resObj)!=TCL_OK) {
 	Tcl_SetChannelError(rcPtr->chan, resObj);
         goto invalid;
     }
@@ -1639,8 +1596,6 @@ ReflectWatch(
     ReflectedChannel *rcPtr = clientData;
     Tcl_Obj *maskObj;
 
-    /* ASSERT rcPtr->methods & FLAG(METH_WATCH) */
-
     /*
      * We restrict the interest to what the channel can support. IOW there
      * will never be write events for a channel which is not writable.
@@ -1683,7 +1638,7 @@ ReflectWatch(
 
     maskObj = DecodeEventMask(mask);
     /* assert maskObj.refCount == 1 */
-    (void) InvokeTclMethod(rcPtr, "watch", maskObj, NULL, NULL);
+    (void) InvokeTclMethod(rcPtr, METH_WATCH, maskObj, NULL, NULL);
     Tcl_DecrRefCount(maskObj);
 
     Tcl_Release(rcPtr);
@@ -1742,7 +1697,7 @@ ReflectBlock(
 
     Tcl_Preserve(rcPtr);
 
-    if (InvokeTclMethod(rcPtr, "blocking", blockObj, NULL, &resObj)!=TCL_OK) {
+    if (InvokeTclMethod(rcPtr,METH_BLOCKING,blockObj,NULL,&resObj)!=TCL_OK) {
 	Tcl_SetChannelError(rcPtr->chan, resObj);
 	errorNum = EINVAL;
     } else {
@@ -1854,7 +1809,7 @@ ReflectSetOption(
     Tcl_IncrRefCount(optionObj);
     Tcl_IncrRefCount(valueObj);
 
-    result = InvokeTclMethod(rcPtr, "configure",optionObj,valueObj, &resObj);
+    result = InvokeTclMethod(rcPtr, METH_CONFIGURE,optionObj,valueObj, &resObj);
     if (result != TCL_OK) {
 	UnmarshallErrorResult(interp, resObj);
     }
@@ -1899,7 +1854,7 @@ ReflectGetOption(
     Tcl_Obj *resObj;		/* Result data for 'configure' */
     int listc, result = TCL_OK;
     Tcl_Obj **listv;
-    const char *method;
+    MethodName method;
 
     /*
      * Are we in the correct thread?
@@ -1938,14 +1893,14 @@ ReflectGetOption(
 	 * Retrieve all options.
 	 */
 
-	method = "cgetall";
+	method = METH_CGETALL;
 	optionObj = NULL;
     } else {
 	/*
 	 * Retrieve the value of one option.
 	 */
 
-	method = "cget";
+	method = METH_CGET;
 	optionObj = Tcl_NewStringObj(optionName, -1);
         Tcl_IncrRefCount(optionObj);
     }
@@ -2159,16 +2114,13 @@ NewReflectedChannel(
     Tcl_Obj *handleObj)
 {
     ReflectedChannel *rcPtr;
-    int i, listc;
-    Tcl_Obj **listv;
+    MethodName mn = METH_BLOCKING;
 
     rcPtr = ckalloc(sizeof(ReflectedChannel));
 
     /* rcPtr->chan: Assigned by caller. Dummy data here. */
-    /* rcPtr->methods: Assigned by caller. Dummy data here. */
 
     rcPtr->chan = NULL;
-    rcPtr->methods = 0;
     rcPtr->interp = interp;
     rcPtr->dead = 0;
 #ifdef TCL_THREADS
@@ -2177,54 +2129,17 @@ NewReflectedChannel(
     rcPtr->mode = mode;
     rcPtr->interest = 0;		/* Initially no interest registered */
 
-    /*
-     * Method placeholder.
-     */
-
     /* ASSERT: cmdpfxObj is a Tcl List */
-
-    Tcl_ListObjGetElements(interp, cmdpfxObj, &listc, &listv);
-
-    /*
-     * See [==] as well.
-     * Storage for the command prefix and the additional words required for
-     * the invocation of methods in the command handler.
-     *
-     * listv [0] [listc-1] | [listc]  [listc+1] |
-     * argv  [0]   ... [.] | [argc-2] [argc-1]  | [argc]  [argc+2]
-     *       cmd   ... pfx | method   chan      | detail1 detail2
-     */
-
-    rcPtr->argc = listc + 2;
-    rcPtr->argv = ckalloc(sizeof(Tcl_Obj *) * (listc+4));
-
-    /*
-     * Duplicate object references.
-     */
-
-    for (i=0; i<listc ; i++) {
-	Tcl_Obj *word = rcPtr->argv[i] = listv[i];
-
-	Tcl_IncrRefCount(word);
-    }
-
-    i++;				/* Skip placeholder for method */
-
-    /*
-     * [Bug 1667990]: See [x] in FreeReflectedChannel for release
-     */
-
-    rcPtr->argv[i] = handleObj;
-    Tcl_IncrRefCount(handleObj);
-
-    /*
-     * The next two objects are kept empty, varying arguments.
-     */
-
-    /*
-     * Initialization complete.
-     */
-
+    rcPtr->cmd = TclListObjCopy(NULL, cmdpfxObj);
+    Tcl_IncrRefCount(rcPtr->cmd);
+    rcPtr->methods = Tcl_NewListObj(METH_WRITE + 1, NULL);
+    while (mn <= METH_WRITE) {
+	Tcl_ListObjAppendElement(NULL, rcPtr->methods,
+		Tcl_NewStringObj(methodNames[mn++], -1));
+    }
+    Tcl_IncrRefCount(rcPtr->methods);
+    rcPtr->name = handleObj;
+    Tcl_IncrRefCount(rcPtr->name);
     return rcPtr;
 }
 
@@ -2271,45 +2186,15 @@ NextHandle(void)
 }
 
 static void
-FreeReflectedChannelArgs(
-    ReflectedChannel *rcPtr)
-{
-    int i, n = rcPtr->argc - 2;
-
-    if (n < 0) {
-	return;
-    }
-    for (i=0; i<n; i++) {
-	Tcl_DecrRefCount(rcPtr->argv[i]);
-    }
-
-    /*
-     * [Bug 1667990]: See [x] in NewReflectedChannel for lock. n+1 = argc-1.
-     */
-
-    Tcl_DecrRefCount(rcPtr->argv[n+1]);
-
-    rcPtr->argc = 1;
-}
-
-static void
 FreeReflectedChannel(
     ReflectedChannel *rcPtr)
 {
     Channel *chanPtr = (Channel *) rcPtr->chan;
 
-    if (chanPtr->typePtr != &tclRChannelType) {
-	/*
-	 * Delete a cloned ChannelType structure.
-	 */
-
-	ckfree(chanPtr->typePtr);
-	chanPtr->typePtr = NULL;
-    }
-
-    FreeReflectedChannelArgs(rcPtr);
-
-    ckfree(rcPtr->argv);
+    Tcl_Release(chanPtr);
+    Tcl_DecrRefCount(rcPtr->name);
+    Tcl_DecrRefCount(rcPtr->methods);
+    Tcl_DecrRefCount(rcPtr->cmd);
     ckfree(rcPtr);
 }
 
@@ -2340,16 +2225,16 @@ FreeReflectedChannel(
 static int
 InvokeTclMethod(
     ReflectedChannel *rcPtr,
-    const char *method,
+    MethodName method,
     Tcl_Obj *argOneObj,		/* NULL'able */
     Tcl_Obj *argTwoObj,		/* NULL'able */
     Tcl_Obj **resultObjPtr)	/* NULL'able */
 {
-    int cmdc;			/* #words in constructed command */
     Tcl_Obj *methObj = NULL;	/* Method name in object form */
     Tcl_InterpState sr;		/* State of handler interp */
     int result;			/* Result code of method invokation */
     Tcl_Obj *resObj = NULL;	/* Result of method invokation. */
+    Tcl_Obj *cmd;
 
     if (rcPtr->dead) {
 	/*
@@ -2372,19 +2257,15 @@ InvokeTclMethod(
     }
 
     /*
-     * NOTE (5): Decide impl. issue: Cache objects with method names? Needs
-     * TSD data as reflections can be created in many different threads.
-     * NO: Caching of command resolutions means storage per channel.
-     */
-
-    /*
-     * Insert method into the pre-allocated area, after the command prefix,
+     * Insert method into the callback command, after the command prefix,
      * before the channel id.
      */
 
-    methObj = Tcl_NewStringObj(method, -1);
-    Tcl_IncrRefCount(methObj);
-    rcPtr->argv[rcPtr->argc - 2] = methObj;
+    cmd = TclListObjCopy(NULL, rcPtr->cmd);
+
+    Tcl_ListObjIndex(NULL, rcPtr->methods, method, &methObj);
+    Tcl_ListObjAppendElement(NULL, cmd, methObj);
+    Tcl_ListObjAppendElement(NULL, cmd, rcPtr->name);
 
     /*
      * Append the additional argument containing method specific details
@@ -2394,13 +2275,10 @@ InvokeTclMethod(
      * The objects will survive the Tcl_EvalObjv without change.
      */
 
-    cmdc = rcPtr->argc;
     if (argOneObj) {
-	rcPtr->argv[cmdc] = argOneObj;
-	cmdc++;
+	Tcl_ListObjAppendElement(NULL, cmd, argOneObj);
 	if (argTwoObj) {
-	    rcPtr->argv[cmdc] = argTwoObj;
-	    cmdc++;
+	    Tcl_ListObjAppendElement(NULL, cmd, argTwoObj);
 	}
     }
 
@@ -2409,9 +2287,10 @@ InvokeTclMethod(
      * existing state intact.
      */
 
+    Tcl_IncrRefCount(cmd);
     sr = Tcl_SaveInterpState(rcPtr->interp, 0 /* Dummy */);
     Tcl_Preserve(rcPtr->interp);
-    result = Tcl_EvalObjv(rcPtr->interp, cmdc, rcPtr->argv, TCL_EVAL_GLOBAL);
+    result = Tcl_EvalObjEx(rcPtr->interp, cmd, TCL_EVAL_GLOBAL);
 
     /*
      * We do not try to extract the result information if the caller has no
@@ -2437,7 +2316,6 @@ InvokeTclMethod(
 	     */
 
 	    if (result != TCL_ERROR) {
-		Tcl_Obj *cmd = Tcl_NewListObj(cmdc, rcPtr->argv);
 		int cmdLen;
 		const char *cmdString = Tcl_GetStringFromObj(cmd, &cmdLen);
 
@@ -2451,25 +2329,17 @@ InvokeTclMethod(
 		result = TCL_ERROR;
 	    }
 	    Tcl_AppendObjToErrorInfo(rcPtr->interp, Tcl_ObjPrintf(
-		    "\n    (chan handler subcommand \"%s\")", method));
+		    "\n    (chan handler subcommand \"%s\")",
+		    methodNames[method]));
 	    resObj = MarshallError(rcPtr->interp);
 	}
 	Tcl_IncrRefCount(resObj);
     }
+    Tcl_DecrRefCount(cmd);
     Tcl_RestoreInterpState(rcPtr->interp, sr);
     Tcl_Release(rcPtr->interp);
 
     /*
-     * Cleanup of the dynamic parts of the command.
-     *
-     * The detail objects survived the Tcl_EvalObjv without change because of
-     * the contract. Therefore there is no need to decrement the refcounts. Only
-     * the internal method object has to be disposed of.
-     */
-
-    Tcl_DecrRefCount(methObj);
-
-    /*
      * The resObj has a ref count of 1 at this location. This means that the
      * caller of InvokeTclMethod has to dispose of it (but only if it was
      * returned to it).
@@ -2657,6 +2527,11 @@ DeleteReflectedChannelMap(
 	/*
 	 * The receiver for the event exited, before processing the event. We
 	 * detach the result now, wake the originator up and signal failure.
+         *
+         * Attention: Results may have been detached already, by either the
+         * receiver, or this thread, as part of other parts in the thread
+         * teardown. Such results are ignored. See ticket [b47b176adf] for the
+         * identical race condition in Tcl 8.6 IORTrans.
 	 */
 
 	evPtr = resultPtr->evPtr;
@@ -2666,6 +2541,9 @@ DeleteReflectedChannelMap(
 	    continue;
 	}
 	paramPtr = evPtr->param;
+	if (!evPtr) {
+	    continue;
+	}
 
 	evPtr->resultPtr = NULL;
 	resultPtr->evPtr = NULL;
@@ -2700,7 +2578,6 @@ DeleteReflectedChannelMap(
 	}
 
 	rcPtr->dead = 1;
-	FreeReflectedChannelArgs(rcPtr);
 	Tcl_DeleteHashEntry(hPtr);
     }
 #endif
@@ -2797,6 +2674,11 @@ DeleteThreadReflectedChannelMap(
 	/*
 	 * The receiver for the event exited, before processing the event. We
 	 * detach the result now, wake the originator up and signal failure.
+         *
+         * Attention: Results may have been detached already, by either the
+         * receiver, or this thread, as part of other parts in the thread
+         * teardown. Such results are ignored. See ticket [b47b176adf] for the
+         * identical race condition in Tcl 8.6 IORTrans.
 	 */
 
 	evPtr = resultPtr->evPtr;
@@ -2806,6 +2688,9 @@ DeleteThreadReflectedChannelMap(
 	    continue;
 	}
 	paramPtr = evPtr->param;
+	if (!evPtr) {
+	    continue;
+	}
 
 	evPtr->resultPtr = NULL;
 	resultPtr->evPtr = NULL;
@@ -2840,7 +2725,6 @@ DeleteThreadReflectedChannelMap(
 	ReflectedChannel *rcPtr = Tcl_GetChannelInstanceData(chan);
 
 	rcPtr->dead = 1;
-	FreeReflectedChannelArgs(rcPtr);
 	Tcl_DeleteHashEntry(hPtr);
     }
     ckfree(rcmPtr);
@@ -3018,17 +2902,19 @@ ForwardProc(
 	 * call upon for the driver.
 	 */
 
-    case ForwardedClose:
+    case ForwardedClose: {
 	/*
 	 * No parameters/results.
 	 */
 
-	if (InvokeTclMethod(rcPtr, "finalize", NULL, NULL, &resObj)!=TCL_OK) {
+	const Tcl_ChannelType *tctPtr;
+
+	if (InvokeTclMethod(rcPtr, METH_FINAL, NULL, NULL, &resObj)!=TCL_OK) {
 	    ForwardSetObjError(paramPtr, resObj);
 	}
 
 	/*
-	 * Freeing is done here, in the origin thread, because the argv[]
+	 * Freeing is done here, in the origin thread, callback command
 	 * objects belong to this thread. Deallocating them in a different
 	 * thread is not allowed
 	 *
@@ -3047,15 +2933,21 @@ ForwardProc(
                 Tcl_GetChannelName(rcPtr->chan));
 	Tcl_DeleteHashEntry(hPtr);
 
-	FreeReflectedChannelArgs(rcPtr);
+	tctPtr = ((Channel *)rcPtr->chan)->typePtr;
+	if (tctPtr && tctPtr != &tclRChannelType) {
+	    ckfree((char *)tctPtr);
+	    ((Channel *)rcPtr->chan)->typePtr = NULL;
+	}
+        Tcl_EventuallyFree(rcPtr, (Tcl_FreeProc *) FreeReflectedChannel);
 	break;
+    }
 
     case ForwardedInput: {
 	Tcl_Obj *toReadObj = Tcl_NewIntObj(paramPtr->input.toRead);
         Tcl_IncrRefCount(toReadObj);
 
         Tcl_Preserve(rcPtr);
-	if (InvokeTclMethod(rcPtr, "read", toReadObj, NULL, &resObj)!=TCL_OK){
+	if (InvokeTclMethod(rcPtr, METH_READ, toReadObj, NULL, &resObj)!=TCL_OK){
 	    int code = ErrnoReturn(rcPtr, resObj);
 
 	    if (code < 0) {
@@ -3095,7 +2987,7 @@ ForwardProc(
         Tcl_IncrRefCount(bufObj);
 
         Tcl_Preserve(rcPtr);
-	if (InvokeTclMethod(rcPtr, "write", bufObj, NULL, &resObj) != TCL_OK) {
+	if (InvokeTclMethod(rcPtr, METH_WRITE, bufObj, NULL, &resObj) != TCL_OK) {
 	    int code = ErrnoReturn(rcPtr, resObj);
 
 	    if (code < 0) {
@@ -3138,7 +3030,7 @@ ForwardProc(
         Tcl_IncrRefCount(baseObj);
 
         Tcl_Preserve(rcPtr);
-	if (InvokeTclMethod(rcPtr, "seek", offObj, baseObj, &resObj)!=TCL_OK){
+	if (InvokeTclMethod(rcPtr, METH_SEEK, offObj, baseObj, &resObj)!=TCL_OK){
 	    ForwardSetObjError(paramPtr, resObj);
 	    paramPtr->seek.offset = -1;
 	} else {
@@ -3174,7 +3066,7 @@ ForwardProc(
         /* assert maskObj.refCount == 1 */
 
         Tcl_Preserve(rcPtr);
-	(void) InvokeTclMethod(rcPtr, "watch", maskObj, NULL, NULL);
+	(void) InvokeTclMethod(rcPtr, METH_WATCH, maskObj, NULL, NULL);
 	Tcl_DecrRefCount(maskObj);
         Tcl_Release(rcPtr);
 	break;
@@ -3185,7 +3077,7 @@ ForwardProc(
 
         Tcl_IncrRefCount(blockObj);
         Tcl_Preserve(rcPtr);
-	if (InvokeTclMethod(rcPtr, "blocking", blockObj, NULL,
+	if (InvokeTclMethod(rcPtr, METH_BLOCKING, blockObj, NULL,
                 &resObj) != TCL_OK) {
 	    ForwardSetObjError(paramPtr, resObj);
 	}
@@ -3201,7 +3093,7 @@ ForwardProc(
         Tcl_IncrRefCount(optionObj);
         Tcl_IncrRefCount(valueObj);
         Tcl_Preserve(rcPtr);
-	if (InvokeTclMethod(rcPtr, "configure", optionObj, valueObj,
+	if (InvokeTclMethod(rcPtr, METH_CONFIGURE, optionObj, valueObj,
                 &resObj) != TCL_OK) {
 	    ForwardSetObjError(paramPtr, resObj);
 	}
@@ -3220,7 +3112,7 @@ ForwardProc(
 
         Tcl_IncrRefCount(optionObj);
         Tcl_Preserve(rcPtr);
-	if (InvokeTclMethod(rcPtr, "cget", optionObj, NULL, &resObj)!=TCL_OK){
+	if (InvokeTclMethod(rcPtr, METH_CGET, optionObj, NULL, &resObj)!=TCL_OK){
 	    ForwardSetObjError(paramPtr, resObj);
 	} else {
 	    TclDStringAppendObj(paramPtr->getOpt.value, resObj);
@@ -3236,7 +3128,7 @@ ForwardProc(
 	 */
 
         Tcl_Preserve(rcPtr);
-	if (InvokeTclMethod(rcPtr, "cgetall", NULL, NULL, &resObj) != TCL_OK){
+	if (InvokeTclMethod(rcPtr, METH_CGETALL, NULL, NULL, &resObj) != TCL_OK){
 	    ForwardSetObjError(paramPtr, resObj);
 	} else {
 	    /*
diff --git a/generic/tclIORTrans.c b/generic/tclIORTrans.c
index 1de635f..d2707a1 100644
--- a/generic/tclIORTrans.c
+++ b/generic/tclIORTrans.c
@@ -457,8 +457,7 @@ static void		TimerKill(ReflectedTransform *rtPtr);
 static void		TimerSetup(ReflectedTransform *rtPtr);
 static void		TimerRun(ClientData clientData);
 static int		TransformRead(ReflectedTransform *rtPtr,
-			    int *errorCodePtr, unsigned char *buf,
-			    int toRead);
+			    int *errorCodePtr, Tcl_Obj *bufObj);
 static int		TransformWrite(ReflectedTransform *rtPtr,
 			    int *errorCodePtr, unsigned char *buf,
 			    int toWrite);
@@ -1063,6 +1062,7 @@ ReflectInput(
 {
     ReflectedTransform *rtPtr = clientData;
     int gotBytes, copied, readBytes;
+    Tcl_Obj *bufObj;
 
     /*
      * The following check can be done before thread redirection, because we
@@ -1078,6 +1078,9 @@ ReflectInput(
 
     Tcl_Preserve(rtPtr);
 
+    /* TODO: Consider a more appropriate buffer size. */
+    bufObj = Tcl_NewByteArrayObj(NULL, toRead);
+    Tcl_IncrRefCount(bufObj);
     gotBytes = 0;
     while (toRead > 0) {
 	/*
@@ -1129,52 +1132,40 @@ ReflectInput(
 	    goto stop;
 	}
 
-	readBytes = Tcl_ReadRaw(rtPtr->parent, buf, toRead);
+
+	readBytes = Tcl_ReadRaw(rtPtr->parent,
+		(char *) Tcl_SetByteArrayLength(bufObj, toRead), toRead);
 	if (readBytes < 0) {
-	    /*
-	     * Report errors to caller. The state of the seek system is
-	     * unchanged!
-	     */
+	    if (Tcl_InputBlocked(rtPtr->parent) && (gotBytes > 0)) {
 
-	    if ((Tcl_GetErrno() == EAGAIN) && (gotBytes > 0)) {
 		/*
-		 * EAGAIN is a special situation. If we had some data before
-		 * we report that instead of the request to re-try.
+		 * Down channel is blocked and offers zero additional bytes.
+		 * The nonzero gotBytes already returned makes the total
+		 * operation a valid short read.  Return to caller.
 		 */
 
 		goto stop;
 	    }
 
+	    /*
+	     * Either the down channel is not blocked (a real error)
+	     * or it is and there are gotBytes==0 byte copied so far.
+	     * In either case, pass up the error, so we either report
+	     * any real error, or do not mistakenly signal EOF by
+	     * returning 0 to the caller.
+	     */
+
 	    *errorCodePtr = Tcl_GetErrno();
 	    goto error;
 	}
 
 	if (readBytes == 0) {
+
 	    /*
-	     * Check wether we hit on EOF in 'parent' or not. If not
-	     * differentiate between blocking and non-blocking modes. In
-	     * non-blocking mode we ran temporarily out of data. Signal this
-	     * to the caller via EWOULDBLOCK and error return (-1). In the
-	     * other cases we simply return what we got and let the caller
-	     * wait for more. On the other hand, if we got an EOF we have to
-	     * convert and flush all waiting partial data.
+	     * Zero returned from Tcl_ReadRaw() always indicates EOF
+	     * on the down channel.
 	     */
-
-	    if (!Tcl_Eof(rtPtr->parent)) {
-		/*
-		 * The state of the seek system is unchanged!
-		 */
-
-		if ((gotBytes == 0) && rtPtr->nonblocking) {
-		    *errorCodePtr = EWOULDBLOCK;
-		    goto error;
-		}
-		goto stop;
-	    } else {
-		/*
-		 * Eof in parent.
-		 */
-
+	
 		if (rtPtr->readIsDrained) {
 		    goto stop;
 		}
@@ -1198,13 +1189,7 @@ ReflectInput(
 		    goto stop;
 		}
 
-		/*
-		 * Reset eof, force caller to drain result buffer.
-		 */
-
-		((Channel *) rtPtr->parent)->state->flags &= ~CHANNEL_EOF;
 		continue; /* at: while (toRead > 0) */
-	    }
 	} /* readBytes == 0 */
 
 	/*
@@ -1213,12 +1198,20 @@ ReflectInput(
 	 * iteration will put it into the result.
 	 */
 
-	if (!TransformRead(rtPtr, errorCodePtr, UCHARP(buf), readBytes)) {
+	Tcl_SetByteArrayLength(bufObj, readBytes);
+	if (!TransformRead(rtPtr, errorCodePtr, bufObj)) {
 	    goto error;
 	}
+	if (Tcl_IsShared(bufObj)) {
+	    Tcl_DecrRefCount(bufObj);
+	    bufObj = Tcl_NewObj();
+	    Tcl_IncrRefCount(bufObj);
+	}
+	Tcl_SetByteArrayLength(bufObj, 0);
     } /* while toRead > 0 */
 
  stop:
+    Tcl_DecrRefCount(bufObj);
     Tcl_Release(rtPtr);
     return gotBytes;
 
@@ -2010,6 +2003,7 @@ InvokeTclMethod(
 
     sr = Tcl_SaveInterpState(rtPtr->interp, 0 /* Dummy */);
     Tcl_Preserve(rtPtr);
+    Tcl_Preserve(rtPtr->interp);
     result = Tcl_EvalObjv(rtPtr->interp, cmdc, rtPtr->argv, TCL_EVAL_GLOBAL);
 
     /*
@@ -2054,6 +2048,7 @@ InvokeTclMethod(
 	Tcl_IncrRefCount(resObj);
     }
     Tcl_RestoreInterpState(rtPtr->interp, sr);
+    Tcl_Release(rtPtr->interp);
     Tcl_Release(rtPtr);
 
     /*
@@ -2230,6 +2225,9 @@ DeleteReflectedTransformMap(
 	 */
 
 	evPtr = resultPtr->evPtr;
+	if (evPtr == NULL) {
+	    continue;
+	}
 	paramPtr = evPtr->param;
 
 	evPtr->resultPtr = NULL;
@@ -2355,6 +2353,9 @@ DeleteThreadReflectedTransformMap(
 	 */
 
 	evPtr = resultPtr->evPtr;
+	if (evPtr == NULL) {
+	    continue;
+	}
 	paramPtr = evPtr->param;
 
 	evPtr->resultPtr = NULL;
@@ -3065,10 +3066,8 @@ static int
 TransformRead(
     ReflectedTransform *rtPtr,
     int *errorCodePtr,
-    unsigned char *buf,
-    int toRead)
+    Tcl_Obj *bufObj)
 {
-    Tcl_Obj *bufObj;
     Tcl_Obj *resObj;
     int bytec;			/* Number of returned bytes */
     unsigned char *bytev;	/* Array of returned bytes */
@@ -3081,8 +3080,8 @@ TransformRead(
     if (rtPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
-	p.transform.buf = (char *) buf;
-	p.transform.size = toRead;
+	p.transform.buf = (char *) Tcl_GetByteArrayFromObj(bufObj,
+		&(p.transform.size));
 
 	ForwardOpToOwnerThread(rtPtr, ForwardedInput, &p);
 
@@ -3102,12 +3101,8 @@ TransformRead(
     /* ASSERT: rtPtr->method & FLAG(METH_READ) */
     /* ASSERT: rtPtr->mode & TCL_READABLE */
 
-    bufObj = Tcl_NewByteArrayObj((unsigned char *) buf, toRead);
-    Tcl_IncrRefCount(bufObj);
-
     if (InvokeTclMethod(rtPtr, "read", bufObj, NULL, &resObj) != TCL_OK) {
 	Tcl_SetChannelError(rtPtr->chan, resObj);
-	Tcl_DecrRefCount(bufObj);
 	Tcl_DecrRefCount(resObj);	/* Remove reference held from invoke */
 	*errorCodePtr = EINVAL;
 	return 0;
@@ -3116,7 +3111,6 @@ TransformRead(
     bytev = Tcl_GetByteArrayFromObj(resObj, &bytec);
     ResultAdd(&rtPtr->result, bytev, bytec);
 
-    Tcl_DecrRefCount(bufObj);
     Tcl_DecrRefCount(resObj);		/* Remove reference held from invoke */
     return 1;
 }
diff --git a/generic/tclIOUtil.c b/generic/tclIOUtil.c
index 6259216..d2919fc 100644
--- a/generic/tclIOUtil.c
+++ b/generic/tclIOUtil.c
@@ -19,11 +19,17 @@
  */
 
 #include "tclInt.h"
-#ifdef __WIN32__
+#ifdef _WIN32
 #   include "tclWinInt.h"
 #endif
 #include "tclFileSystem.h"
 
+#ifdef TCL_TEMPLOAD_NO_UNLINK
+#ifndef NO_FSTATFS
+#include <sys/statfs.h>
+#endif
+#endif
+
 /*
  * struct FilesystemRecord --
  *
@@ -792,7 +798,7 @@ TclFinalizeFilesystem(void)
      * filesystem is likely to fail.
      */
 
-#ifdef __WIN32__
+#ifdef _WIN32
     TclWinEncodingsCleanup();
 #endif
 }
@@ -819,7 +825,7 @@ TclResetFilesystem(void)
     filesystemList = &nativeFilesystemRecord;
     theFilesystemEpoch++;
 
-#ifdef __WIN32__
+#ifdef _WIN32
     /*
      * Cleans up the win32 API filesystem proc lookup table. This must happen
      * very late in finalization so that deleting of copied dlls can occur.
@@ -3110,6 +3116,82 @@ Tcl_FSLoadFile(
  *----------------------------------------------------------------------
  */
 
+/*
+ * Workaround for issue with modern HPUX which do allow the unlink (no ETXTBSY
+ * error) yet somehow trash some internal data structures which prevents the
+ * second and further shared libraries from getting properly loaded. Only the
+ * first is ok. We try to get around the issue by not unlinking,
+ * i.e. emulating the behaviour of the older HPUX which denied removal.
+ *
+ * Doing the unlink is also an issue within docker containers, whose AUFS
+ * bungles this as well, see
+ *     https://github.com/dotcloud/docker/issues/1911
+ *
+ * For these situations the change below makes the execution of the unlink
+ * semi-controllable at runtime.
+ *
+ *     An AUFS filesystem (if it can be detected) will force avoidance of
+ *     unlink. The env variable TCL_TEMPLOAD_NO_UNLINK allows detection of a
+ *     users general request (unlink and not.
+ *
+ * By default the unlink is done (if not in AUFS). However if the variable is
+ * present and set to true (any integer > 0) then the unlink is skipped.
+ */
+
+int
+TclSkipUnlink (Tcl_Obj* shlibFile)
+{
+    /* Order of testing:
+     * 1. On hpux we generally want to skip unlink in general
+     *
+     * Outside of hpux then:
+     * 2. For a general user request   (TCL_TEMPLOAD_NO_UNLINK present, non-empty, => int)
+     * 3. For general AUFS environment (statfs, if available).
+     *
+     * Ad 2: This variable can disable/override the AUFS detection, i.e. for
+     * testing if a newer AUFS does not have the bug any more.
+     * 
+     * Ad 3: This is conditionally compiled in. Condition currently must be set manually.
+     *       This part needs proper tests in the configure(.in).
+     */
+
+#ifdef hpux
+    return 1;
+#else
+    char* skipstr;
+
+    skipstr = getenv ("TCL_TEMPLOAD_NO_UNLINK");
+    if (skipstr && (skipstr[0] != '\0')) {
+	return atoi(skipstr);
+    }
+
+#ifdef TCL_TEMPLOAD_NO_UNLINK
+#ifndef NO_FSTATFS
+    {
+	struct statfs fs;
+	/* Have fstatfs. May not have the AUFS super magic ... Indeed our build
+	 * box is too old to have it directly in the headers. Define taken from
+	 *     http://mooon.googlecode.com/svn/trunk/linux_include/linux/aufs_type.h
+	 *     http://aufs.sourceforge.net/
+	 * Better reference will be gladly taken.
+	 */
+#ifndef AUFS_SUPER_MAGIC
+#define AUFS_SUPER_MAGIC ('a' << 24 | 'u' << 16 | 'f' << 8 | 's')
+#endif /* AUFS_SUPER_MAGIC */
+	if ((statfs(Tcl_GetString (shlibFile), &fs) == 0) &&
+	    (fs.f_type == AUFS_SUPER_MAGIC)) {
+	    return 1;
+	}
+    }
+#endif /* ... NO_FSTATFS */
+#endif /* ... TCL_TEMPLOAD_NO_UNLINK */
+
+    /* Fallback: !hpux, no EV override, no AUFS (detection, nor detected):
+     * Don't skip */
+    return 0;
+#endif /* hpux */
+}
+
 int
 Tcl_LoadFile(
     Tcl_Interp *interp,		/* Used for error reporting. */
@@ -3255,7 +3337,7 @@ Tcl_LoadFile(
 	return TCL_ERROR;
     }
 
-#ifndef __WIN32__
+#ifndef _WIN32
     /*
      * Do we need to set appropriate permissions on the file? This may be
      * required on some systems. On Unix we could loop over the file
@@ -3300,7 +3382,9 @@ Tcl_LoadFile(
      * avoids any worries about leaving the copy laying around on exit.
      */
 
-    if (Tcl_FSDeleteFile(copyToPtr) == TCL_OK) {
+    if (
+	!TclSkipUnlink (copyToPtr) &&
+	(Tcl_FSDeleteFile(copyToPtr) == TCL_OK)) {
 	Tcl_DecrRefCount(copyToPtr);
 
 	/*
diff --git a/generic/tclInt.h b/generic/tclInt.h
index 2aa1725..9a2e8dd 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -2453,6 +2453,30 @@ typedef struct List {
 #endif
 
 /*
+ * Macro used to save a function call for common uses of
+ * Tcl_GetWideIntFromObj(). The ANSI C "prototype" is:
+ *
+ * MODULE_SCOPE int TclGetWideIntFromObj(Tcl_Interp *interp, Tcl_Obj *objPtr,
+ *			Tcl_WideInt *wideIntPtr);
+ */
+
+#ifdef TCL_WIDE_INT_IS_LONG
+#define TclGetWideIntFromObj(interp, objPtr, wideIntPtr) \
+    (((objPtr)->typePtr == &tclIntType)					\
+	? (*(wideIntPtr) = (Tcl_WideInt)				\
+		((objPtr)->internalRep.longValue), TCL_OK) :		\
+	Tcl_GetWideIntFromObj((interp), (objPtr), (wideIntPtr)))
+#else /* !TCL_WIDE_INT_IS_LONG */
+#define TclGetWideIntFromObj(interp, objPtr, wideIntPtr)		\
+    (((objPtr)->typePtr == &tclWideIntType)				\
+	? (*(wideIntPtr) = (objPtr)->internalRep.wideValue, TCL_OK) :	\
+    ((objPtr)->typePtr == &tclIntType)					\
+	? (*(wideIntPtr) = (Tcl_WideInt)				\
+		((objPtr)->internalRep.longValue), TCL_OK) :		\
+	Tcl_GetWideIntFromObj((interp), (objPtr), (wideIntPtr)))
+#endif /* TCL_WIDE_INT_IS_LONG */
+
+/*
  * Flag values for TclTraceDictPath().
  *
  * DICT_PATH_READ indicates that all entries on the path must exist but no
@@ -2857,6 +2881,10 @@ MODULE_SCOPE void	TclContinuationsCopy(Tcl_Obj *objPtr,
 MODULE_SCOPE int	TclConvertElement(const char *src, int length,
 			    char *dst, int flags);
 MODULE_SCOPE void	TclDeleteNamespaceVars(Namespace *nsPtr);
+MODULE_SCOPE int	TclFindDictElement(Tcl_Interp *interp,
+			    const char *dict, int dictLength,
+			    const char **elementPtr, const char **nextPtr,
+			    int *sizePtr, int *literalPtr);
 /* TIP #280 - Modified token based evulation, with line information. */
 MODULE_SCOPE int	TclEvalEx(Tcl_Interp *interp, const char *script,
 			    int numBytes, int flags, int line,
@@ -2896,6 +2924,7 @@ MODULE_SCOPE void	TclFinalizeObjects(void);
 MODULE_SCOPE void	TclFinalizePreserve(void);
 MODULE_SCOPE void	TclFinalizeSynchronization(void);
 MODULE_SCOPE void	TclFinalizeThreadAlloc(void);
+MODULE_SCOPE void	TclFinalizeThreadAllocThread(void);
 MODULE_SCOPE void	TclFinalizeThreadData(void);
 MODULE_SCOPE void	TclFinalizeThreadObjects(void);
 MODULE_SCOPE double	TclFloor(const mp_int *a);
@@ -2921,6 +2950,8 @@ MODULE_SCOPE int	TclGetOpenModeEx(Tcl_Interp *interp,
 MODULE_SCOPE Tcl_Obj *	TclGetProcessGlobalValue(ProcessGlobalValue *pgvPtr);
 MODULE_SCOPE Tcl_Obj *	TclGetSourceFromFrame(CmdFrame *cfPtr, int objc,
 			    Tcl_Obj *const objv[]);
+MODULE_SCOPE char *	TclGetStringStorage(Tcl_Obj *objPtr,
+			    unsigned int *sizePtr);
 MODULE_SCOPE int	TclGlob(Tcl_Interp *interp, char *pattern,
 			    Tcl_Obj *unquotedPrefix, int globFlags,
 			    Tcl_GlobTypeData *types);
diff --git a/generic/tclIntPlatDecls.h b/generic/tclIntPlatDecls.h
index 72719fe..ac06787 100644
--- a/generic/tclIntPlatDecls.h
+++ b/generic/tclIntPlatDecls.h
@@ -13,7 +13,7 @@
 #ifndef _TCLINTPLATDECLS
 #define _TCLINTPLATDECLS
 
-#ifdef __WIN32__
+#ifdef _WIN32
 #   define Tcl_DirEntry void
 #   define DIR void
 #endif
@@ -45,7 +45,7 @@ extern "C" {
  * Exported function declarations:
  */
 
-#if !defined(__WIN32__) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
 /* 0 */
 EXTERN void		TclGetAndDetachPids(Tcl_Interp *interp,
 				Tcl_Channel chan);
@@ -104,7 +104,7 @@ EXTERN int		TclUnixOpenTemporaryFile(Tcl_Obj *dirObj,
 				Tcl_Obj *basenameObj, Tcl_Obj *extensionObj,
 				Tcl_Obj *resultingNameObj);
 #endif /* UNIX */
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
 /* 0 */
 EXTERN void		TclWinConvertError(DWORD errCode);
 /* 1 */
@@ -258,7 +258,7 @@ typedef struct TclIntPlatStubs {
     int magic;
     void *hooks;
 
-#if !defined(__WIN32__) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
     void (*tclGetAndDetachPids) (Tcl_Interp *interp, Tcl_Channel chan); /* 0 */
     int (*tclpCloseFile) (TclFile file); /* 1 */
     Tcl_Channel (*tclpCreateCommandChannel) (TclFile readFile, TclFile writeFile, TclFile errorFile, int numPids, Tcl_Pid *pidPtr); /* 2 */
@@ -291,7 +291,7 @@ typedef struct TclIntPlatStubs {
     int (*tclWinCPUID) (unsigned int index, unsigned int *regs); /* 29 */
     int (*tclUnixOpenTemporaryFile) (Tcl_Obj *dirObj, Tcl_Obj *basenameObj, Tcl_Obj *extensionObj, Tcl_Obj *resultingNameObj); /* 30 */
 #endif /* UNIX */
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
     void (*tclWinConvertError) (DWORD errCode); /* 0 */
     void (*tclWinConvertWSAError) (DWORD errCode); /* 1 */
     struct servent * (*tclWinGetServByName) (const char *nm, const char *proto); /* 2 */
@@ -371,7 +371,7 @@ extern const TclIntPlatStubs *tclIntPlatStubsPtr;
  * Inline function declarations:
  */
 
-#if !defined(__WIN32__) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
 #define TclGetAndDetachPids \
 	(tclIntPlatStubsPtr->tclGetAndDetachPids) /* 0 */
 #define TclpCloseFile \
@@ -420,7 +420,7 @@ extern const TclIntPlatStubs *tclIntPlatStubsPtr;
 #define TclUnixOpenTemporaryFile \
 	(tclIntPlatStubsPtr->tclUnixOpenTemporaryFile) /* 30 */
 #endif /* UNIX */
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
 #define TclWinConvertError \
 	(tclIntPlatStubsPtr->tclWinConvertError) /* 0 */
 #define TclWinConvertWSAError \
@@ -550,9 +550,15 @@ extern const TclIntPlatStubs *tclIntPlatStubsPtr;
 #undef TclpInetNtoa
 #define TclpInetNtoa inet_ntoa
 
-#if defined(__WIN32__) || defined(__CYGWIN__)
+#if defined(_WIN32)
 #   undef TclWinNToHS
+#   undef TclWinGetServByName
+#   undef TclWinGetSockOpt
+#   undef TclWinSetSockOpt
 #   define TclWinNToHS ntohs
+#   define TclWinGetServByName getservbyname
+#   define TclWinGetSockOpt getsockopt
+#   define TclWinSetSockOpt setsockopt
 #else
 #   undef TclpGetPid
 #   define TclpGetPid(pid) ((unsigned long) (pid))
diff --git a/generic/tclLoad.c b/generic/tclLoad.c
index 5cacab1..7c70e03 100644
--- a/generic/tclLoad.c
+++ b/generic/tclLoad.c
@@ -830,7 +830,7 @@ Tcl_UnloadObjCmd(
 	 * Unload the shared library from the application memory...
 	 */
 
-#if defined(TCL_UNLOAD_DLLS) || defined(__WIN32__)
+#if defined(TCL_UNLOAD_DLLS) || defined(_WIN32)
 	/*
 	 * Some Unix dlls are poorly behaved - registering things like atexit
 	 * calls that can't be unregistered. If you unload such dlls, you get
@@ -1151,7 +1151,7 @@ TclFinalizeLoad(void)
 	pkgPtr = firstPackagePtr;
 	firstPackagePtr = pkgPtr->nextPtr;
 
-#if defined(TCL_UNLOAD_DLLS) || defined(__WIN32__)
+#if defined(TCL_UNLOAD_DLLS) || defined(_WIN32)
 	/*
 	 * Some Unix dlls are poorly behaved - registering things like atexit
 	 * calls that can't be unregistered. If you unload such dlls, you get
diff --git a/generic/tclMain.c b/generic/tclMain.c
index faea75a..360f5e9 100644
--- a/generic/tclMain.c
+++ b/generic/tclMain.c
@@ -47,7 +47,7 @@
  * we have to translate that to strcmp here.
  */
 
-#ifndef __WIN32__
+#ifndef _WIN32
 #   define TCHAR char
 #   define TEXT(arg) arg
 #   define _tcscmp strcmp
diff --git a/generic/tclOO.decls b/generic/tclOO.decls
index 5d6f2c2..265ba88 100644
--- a/generic/tclOO.decls
+++ b/generic/tclOO.decls
@@ -18,6 +18,7 @@ library tclOO
 
 interface tclOO
 hooks tclOOInt
+scspec TCLAPI
 
 declare 0 {
     Tcl_Object Tcl_CopyObjectInstance(Tcl_Interp *interp,
diff --git a/generic/tclOODecls.h b/generic/tclOODecls.h
index d3b9e59..9fd62ec 100644
--- a/generic/tclOODecls.h
+++ b/generic/tclOODecls.h
@@ -5,19 +5,19 @@
 #ifndef _TCLOODECLS
 #define _TCLOODECLS
 
-#undef TCL_STORAGE_CLASS
-#ifdef BUILD_tcl
-#   define TCL_STORAGE_CLASS DLLEXPORT
-#else
-#   ifdef USE_TCL_STUBS
-#      undef USE_TCLOO_STUBS
-#      define USE_TCLOO_STUBS
-#      define TCL_STORAGE_CLASS
+#ifndef TCLAPI
+#   ifdef BUILD_tcl
+#	define TCLAPI extern DLLEXPORT
 #   else
-#      define TCL_STORAGE_CLASS DLLIMPORT
+#	define TCLAPI extern DLLIMPORT
 #   endif
 #endif
 
+#ifdef USE_TCL_STUBS
+#   undef USE_TCLOO_STUBS
+#   define USE_TCLOO_STUBS
+#endif
+
 /* !BEGIN!: Do not edit below this line. */
 
 #ifdef __cplusplus
@@ -29,92 +29,92 @@ extern "C" {
  */
 
 /* 0 */
-EXTERN Tcl_Object	Tcl_CopyObjectInstance(Tcl_Interp *interp,
+TCLAPI Tcl_Object	Tcl_CopyObjectInstance(Tcl_Interp *interp,
 				Tcl_Object sourceObject,
 				const char *targetName,
 				const char *targetNamespaceName);
 /* 1 */
-EXTERN Tcl_Object	Tcl_GetClassAsObject(Tcl_Class clazz);
+TCLAPI Tcl_Object	Tcl_GetClassAsObject(Tcl_Class clazz);
 /* 2 */
-EXTERN Tcl_Class	Tcl_GetObjectAsClass(Tcl_Object object);
+TCLAPI Tcl_Class	Tcl_GetObjectAsClass(Tcl_Object object);
 /* 3 */
-EXTERN Tcl_Command	Tcl_GetObjectCommand(Tcl_Object object);
+TCLAPI Tcl_Command	Tcl_GetObjectCommand(Tcl_Object object);
 /* 4 */
-EXTERN Tcl_Object	Tcl_GetObjectFromObj(Tcl_Interp *interp,
+TCLAPI Tcl_Object	Tcl_GetObjectFromObj(Tcl_Interp *interp,
 				Tcl_Obj *objPtr);
 /* 5 */
-EXTERN Tcl_Namespace *	Tcl_GetObjectNamespace(Tcl_Object object);
+TCLAPI Tcl_Namespace *	Tcl_GetObjectNamespace(Tcl_Object object);
 /* 6 */
-EXTERN Tcl_Class	Tcl_MethodDeclarerClass(Tcl_Method method);
+TCLAPI Tcl_Class	Tcl_MethodDeclarerClass(Tcl_Method method);
 /* 7 */
-EXTERN Tcl_Object	Tcl_MethodDeclarerObject(Tcl_Method method);
+TCLAPI Tcl_Object	Tcl_MethodDeclarerObject(Tcl_Method method);
 /* 8 */
-EXTERN int		Tcl_MethodIsPublic(Tcl_Method method);
+TCLAPI int		Tcl_MethodIsPublic(Tcl_Method method);
 /* 9 */
-EXTERN int		Tcl_MethodIsType(Tcl_Method method,
+TCLAPI int		Tcl_MethodIsType(Tcl_Method method,
 				const Tcl_MethodType *typePtr,
 				ClientData *clientDataPtr);
 /* 10 */
-EXTERN Tcl_Obj *	Tcl_MethodName(Tcl_Method method);
+TCLAPI Tcl_Obj *	Tcl_MethodName(Tcl_Method method);
 /* 11 */
-EXTERN Tcl_Method	Tcl_NewInstanceMethod(Tcl_Interp *interp,
+TCLAPI Tcl_Method	Tcl_NewInstanceMethod(Tcl_Interp *interp,
 				Tcl_Object object, Tcl_Obj *nameObj,
 				int isPublic, const Tcl_MethodType *typePtr,
 				ClientData clientData);
 /* 12 */
-EXTERN Tcl_Method	Tcl_NewMethod(Tcl_Interp *interp, Tcl_Class cls,
+TCLAPI Tcl_Method	Tcl_NewMethod(Tcl_Interp *interp, Tcl_Class cls,
 				Tcl_Obj *nameObj, int isPublic,
 				const Tcl_MethodType *typePtr,
 				ClientData clientData);
 /* 13 */
-EXTERN Tcl_Object	Tcl_NewObjectInstance(Tcl_Interp *interp,
+TCLAPI Tcl_Object	Tcl_NewObjectInstance(Tcl_Interp *interp,
 				Tcl_Class cls, const char *nameStr,
 				const char *nsNameStr, int objc,
 				Tcl_Obj *const *objv, int skip);
 /* 14 */
-EXTERN int		Tcl_ObjectDeleted(Tcl_Object object);
+TCLAPI int		Tcl_ObjectDeleted(Tcl_Object object);
 /* 15 */
-EXTERN int		Tcl_ObjectContextIsFiltering(
+TCLAPI int		Tcl_ObjectContextIsFiltering(
 				Tcl_ObjectContext context);
 /* 16 */
-EXTERN Tcl_Method	Tcl_ObjectContextMethod(Tcl_ObjectContext context);
+TCLAPI Tcl_Method	Tcl_ObjectContextMethod(Tcl_ObjectContext context);
 /* 17 */
-EXTERN Tcl_Object	Tcl_ObjectContextObject(Tcl_ObjectContext context);
+TCLAPI Tcl_Object	Tcl_ObjectContextObject(Tcl_ObjectContext context);
 /* 18 */
-EXTERN int		Tcl_ObjectContextSkippedArgs(
+TCLAPI int		Tcl_ObjectContextSkippedArgs(
 				Tcl_ObjectContext context);
 /* 19 */
-EXTERN ClientData	Tcl_ClassGetMetadata(Tcl_Class clazz,
+TCLAPI ClientData	Tcl_ClassGetMetadata(Tcl_Class clazz,
 				const Tcl_ObjectMetadataType *typePtr);
 /* 20 */
-EXTERN void		Tcl_ClassSetMetadata(Tcl_Class clazz,
+TCLAPI void		Tcl_ClassSetMetadata(Tcl_Class clazz,
 				const Tcl_ObjectMetadataType *typePtr,
 				ClientData metadata);
 /* 21 */
-EXTERN ClientData	Tcl_ObjectGetMetadata(Tcl_Object object,
+TCLAPI ClientData	Tcl_ObjectGetMetadata(Tcl_Object object,
 				const Tcl_ObjectMetadataType *typePtr);
 /* 22 */
-EXTERN void		Tcl_ObjectSetMetadata(Tcl_Object object,
+TCLAPI void		Tcl_ObjectSetMetadata(Tcl_Object object,
 				const Tcl_ObjectMetadataType *typePtr,
 				ClientData metadata);
 /* 23 */
-EXTERN int		Tcl_ObjectContextInvokeNext(Tcl_Interp *interp,
+TCLAPI int		Tcl_ObjectContextInvokeNext(Tcl_Interp *interp,
 				Tcl_ObjectContext context, int objc,
 				Tcl_Obj *const *objv, int skip);
 /* 24 */
-EXTERN Tcl_ObjectMapMethodNameProc * Tcl_ObjectGetMethodNameMapper(
+TCLAPI Tcl_ObjectMapMethodNameProc * Tcl_ObjectGetMethodNameMapper(
 				Tcl_Object object);
 /* 25 */
-EXTERN void		Tcl_ObjectSetMethodNameMapper(Tcl_Object object,
+TCLAPI void		Tcl_ObjectSetMethodNameMapper(Tcl_Object object,
 				Tcl_ObjectMapMethodNameProc *mapMethodNameProc);
 /* 26 */
-EXTERN void		Tcl_ClassSetConstructor(Tcl_Interp *interp,
+TCLAPI void		Tcl_ClassSetConstructor(Tcl_Interp *interp,
 				Tcl_Class clazz, Tcl_Method method);
 /* 27 */
-EXTERN void		Tcl_ClassSetDestructor(Tcl_Interp *interp,
+TCLAPI void		Tcl_ClassSetDestructor(Tcl_Interp *interp,
 				Tcl_Class clazz, Tcl_Method method);
 /* 28 */
-EXTERN Tcl_Obj *	Tcl_GetObjectName(Tcl_Interp *interp,
+TCLAPI Tcl_Obj *	Tcl_GetObjectName(Tcl_Interp *interp,
 				Tcl_Object object);
 
 typedef struct {
@@ -231,6 +231,4 @@ extern const TclOOStubs *tclOOStubsPtr;
 
 /* !END!: Do not edit above this line. */
 
-#undef TCL_STORAGE_CLASS
-#define TCL_STORAGE_CLASS DLLIMPORT
 #endif /* _TCLOODECLS */
diff --git a/generic/tclOOIntDecls.h b/generic/tclOOIntDecls.h
index 4f70e5b..74a8d81 100644
--- a/generic/tclOOIntDecls.h
+++ b/generic/tclOOIntDecls.h
@@ -5,17 +5,6 @@
 #ifndef _TCLOOINTDECLS
 #define _TCLOOINTDECLS
 
-#undef TCL_STORAGE_CLASS
-#ifdef BUILD_tcl
-#   define TCL_STORAGE_CLASS DLLEXPORT
-#else
-#   ifdef USE_TCL_STUBS
-#      define TCL_STORAGE_CLASS
-#   else
-#      define TCL_STORAGE_CLASS DLLIMPORT
-#   endif
-#endif
-
 /* !BEGIN!: Do not edit below this line. */
 
 #ifdef __cplusplus
@@ -27,46 +16,46 @@ extern "C" {
  */
 
 /* 0 */
-EXTERN Tcl_Object	TclOOGetDefineCmdContext(Tcl_Interp *interp);
+TCLAPI Tcl_Object	TclOOGetDefineCmdContext(Tcl_Interp *interp);
 /* 1 */
-EXTERN Tcl_Method	TclOOMakeProcInstanceMethod(Tcl_Interp *interp,
+TCLAPI Tcl_Method	TclOOMakeProcInstanceMethod(Tcl_Interp *interp,
 				Object *oPtr, int flags, Tcl_Obj *nameObj,
 				Tcl_Obj *argsObj, Tcl_Obj *bodyObj,
 				const Tcl_MethodType *typePtr,
 				ClientData clientData, Proc **procPtrPtr);
 /* 2 */
-EXTERN Tcl_Method	TclOOMakeProcMethod(Tcl_Interp *interp,
+TCLAPI Tcl_Method	TclOOMakeProcMethod(Tcl_Interp *interp,
 				Class *clsPtr, int flags, Tcl_Obj *nameObj,
 				const char *namePtr, Tcl_Obj *argsObj,
 				Tcl_Obj *bodyObj,
 				const Tcl_MethodType *typePtr,
 				ClientData clientData, Proc **procPtrPtr);
 /* 3 */
-EXTERN Method *		TclOONewProcInstanceMethod(Tcl_Interp *interp,
+TCLAPI Method *		TclOONewProcInstanceMethod(Tcl_Interp *interp,
 				Object *oPtr, int flags, Tcl_Obj *nameObj,
 				Tcl_Obj *argsObj, Tcl_Obj *bodyObj,
 				ProcedureMethod **pmPtrPtr);
 /* 4 */
-EXTERN Method *		TclOONewProcMethod(Tcl_Interp *interp, Class *clsPtr,
+TCLAPI Method *		TclOONewProcMethod(Tcl_Interp *interp, Class *clsPtr,
 				int flags, Tcl_Obj *nameObj,
 				Tcl_Obj *argsObj, Tcl_Obj *bodyObj,
 				ProcedureMethod **pmPtrPtr);
 /* 5 */
-EXTERN int		TclOOObjectCmdCore(Object *oPtr, Tcl_Interp *interp,
+TCLAPI int		TclOOObjectCmdCore(Object *oPtr, Tcl_Interp *interp,
 				int objc, Tcl_Obj *const *objv,
 				int publicOnly, Class *startCls);
 /* 6 */
-EXTERN int		TclOOIsReachable(Class *targetPtr, Class *startPtr);
+TCLAPI int		TclOOIsReachable(Class *targetPtr, Class *startPtr);
 /* 7 */
-EXTERN Method *		TclOONewForwardMethod(Tcl_Interp *interp,
+TCLAPI Method *		TclOONewForwardMethod(Tcl_Interp *interp,
 				Class *clsPtr, int isPublic,
 				Tcl_Obj *nameObj, Tcl_Obj *prefixObj);
 /* 8 */
-EXTERN Method *		TclOONewForwardInstanceMethod(Tcl_Interp *interp,
+TCLAPI Method *		TclOONewForwardInstanceMethod(Tcl_Interp *interp,
 				Object *oPtr, int isPublic, Tcl_Obj *nameObj,
 				Tcl_Obj *prefixObj);
 /* 9 */
-EXTERN Tcl_Method	TclOONewProcInstanceMethodEx(Tcl_Interp *interp,
+TCLAPI Tcl_Method	TclOONewProcInstanceMethodEx(Tcl_Interp *interp,
 				Tcl_Object oPtr,
 				TclOO_PreCallProc *preCallPtr,
 				TclOO_PostCallProc *postCallPtr,
@@ -75,7 +64,7 @@ EXTERN Tcl_Method	TclOONewProcInstanceMethodEx(Tcl_Interp *interp,
 				Tcl_Obj *argsObj, Tcl_Obj *bodyObj,
 				int flags, void **internalTokenPtr);
 /* 10 */
-EXTERN Tcl_Method	TclOONewProcMethodEx(Tcl_Interp *interp,
+TCLAPI Tcl_Method	TclOONewProcMethodEx(Tcl_Interp *interp,
 				Tcl_Class clsPtr,
 				TclOO_PreCallProc *preCallPtr,
 				TclOO_PostCallProc *postCallPtr,
@@ -84,22 +73,22 @@ EXTERN Tcl_Method	TclOONewProcMethodEx(Tcl_Interp *interp,
 				Tcl_Obj *argsObj, Tcl_Obj *bodyObj,
 				int flags, void **internalTokenPtr);
 /* 11 */
-EXTERN int		TclOOInvokeObject(Tcl_Interp *interp,
+TCLAPI int		TclOOInvokeObject(Tcl_Interp *interp,
 				Tcl_Object object, Tcl_Class startCls,
 				int publicPrivate, int objc,
 				Tcl_Obj *const *objv);
 /* 12 */
-EXTERN void		TclOOObjectSetFilters(Object *oPtr, int numFilters,
+TCLAPI void		TclOOObjectSetFilters(Object *oPtr, int numFilters,
 				Tcl_Obj *const *filters);
 /* 13 */
-EXTERN void		TclOOClassSetFilters(Tcl_Interp *interp,
+TCLAPI void		TclOOClassSetFilters(Tcl_Interp *interp,
 				Class *classPtr, int numFilters,
 				Tcl_Obj *const *filters);
 /* 14 */
-EXTERN void		TclOOObjectSetMixins(Object *oPtr, int numMixins,
+TCLAPI void		TclOOObjectSetMixins(Object *oPtr, int numMixins,
 				Class *const *mixins);
 /* 15 */
-EXTERN void		TclOOClassSetMixins(Tcl_Interp *interp,
+TCLAPI void		TclOOClassSetMixins(Tcl_Interp *interp,
 				Class *classPtr, int numMixins,
 				Class *const *mixins);
 
@@ -174,6 +163,4 @@ extern const TclOOIntStubs *tclOOIntStubsPtr;
 
 /* !END!: Do not edit above this line. */
 
-#undef TCL_STORAGE_CLASS
-#define TCL_STORAGE_CLASS DLLIMPORT
 #endif /* _TCLOOINTDECLS */
diff --git a/generic/tclPathObj.c b/generic/tclPathObj.c
index b7f3dcf..fe6063f 100644
--- a/generic/tclPathObj.c
+++ b/generic/tclPathObj.c
@@ -512,7 +512,7 @@ TclFSGetPathType(
 
     if (PATHFLAGS(pathPtr) == 0) {
 	/* The path is not absolute... */
-#ifdef __WIN32__
+#ifdef _WIN32
 	/* ... on Windows we must make another call to determine whether
 	 * it's relative or volumerelative [Bug 2571597]. */
 	return TclGetPathType(pathPtr, filesystemPtrPtr, driveNameLengthPtr,
@@ -1956,7 +1956,7 @@ Tcl_FSGetNormalizedPath(
 		/*
 		 * We have a refCount on the cwd.
 		 */
-#ifdef __WIN32__
+#ifdef _WIN32
 	    } else if (type == TCL_PATH_VOLUME_RELATIVE) {
 		/*
 		 * Only Windows has volume-relative paths.
@@ -1969,7 +1969,7 @@ Tcl_FSGetNormalizedPath(
 		    return NULL;
 		}
 		pureNormalized = 0;
-#endif /* __WIN32__ */
+#endif /* _WIN32 */
 	    }
 	}
 
diff --git a/generic/tclPlatDecls.h b/generic/tclPlatDecls.h
index 681854d..abc8ee8 100644
--- a/generic/tclPlatDecls.h
+++ b/generic/tclPlatDecls.h
@@ -50,7 +50,7 @@ extern "C" {
  * Exported function declarations:
  */
 
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
 /* 0 */
 EXTERN TCHAR *		Tcl_WinUtfToTChar(const char *str, int len,
 				Tcl_DString *dsPtr);
@@ -75,7 +75,7 @@ typedef struct TclPlatStubs {
     int magic;
     void *hooks;
 
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
     TCHAR * (*tcl_WinUtfToTChar) (const char *str, int len, Tcl_DString *dsPtr); /* 0 */
     char * (*tcl_WinTCharToUtf) (const TCHAR *str, int len, Tcl_DString *dsPtr); /* 1 */
 #endif /* WIN */
@@ -97,7 +97,7 @@ extern const TclPlatStubs *tclPlatStubsPtr;
  * Inline function declarations:
  */
 
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
 #define Tcl_WinUtfToTChar \
 	(tclPlatStubsPtr->tcl_WinUtfToTChar) /* 0 */
 #define Tcl_WinTCharToUtf \
diff --git a/generic/tclStringObj.c b/generic/tclStringObj.c
index dffa38c..c04944d 100644
--- a/generic/tclStringObj.c
+++ b/generic/tclStringObj.c
@@ -1123,7 +1123,8 @@ Tcl_AppendLimitedToObj(
 	if (ellipsis == NULL) {
 	    ellipsis = "...";
 	}
-	toCopy = Tcl_UtfPrev(bytes+limit+1-strlen(ellipsis), bytes) - bytes;
+	toCopy = (bytes == NULL) ? limit
+		: Tcl_UtfPrev(bytes+limit+1-strlen(ellipsis), bytes) - bytes;
     }
 
     /*
@@ -1435,7 +1436,7 @@ AppendUnicodeToUnicodeRep(
 	 * the reallocs below.
 	 */
 
-	if (unicode >= stringPtr->unicode
+	if (unicode && unicode >= stringPtr->unicode
 		&& unicode <= stringPtr->unicode + stringPtr->maxChars) {
 	    offset = unicode - stringPtr->unicode;
 	}
@@ -1457,8 +1458,10 @@ AppendUnicodeToUnicodeRep(
      * trailing null.
      */
 
-    memmove(stringPtr->unicode + stringPtr->numChars, unicode,
-	    appendNumChars * sizeof(Tcl_UniChar));
+    if (unicode) {
+	memmove(stringPtr->unicode + stringPtr->numChars, unicode,
+		appendNumChars * sizeof(Tcl_UniChar));
+    }
     stringPtr->unicode[numChars] = 0;
     stringPtr->numChars = numChars;
     stringPtr->allocated = 0;
@@ -1597,7 +1600,7 @@ AppendUtfToUtfRep(
 	 * the reallocs below.
 	 */
 
-	if (bytes >= objPtr->bytes
+	if (bytes && bytes >= objPtr->bytes
 		&& bytes <= objPtr->bytes + objPtr->length) {
 	    offset = bytes - objPtr->bytes;
 	}
@@ -1625,7 +1628,9 @@ AppendUtfToUtfRep(
     stringPtr->numChars = -1;
     stringPtr->hasUnicode = 0;
 
-    memmove(objPtr->bytes + oldLength, bytes, numBytes);
+    if (bytes) {
+	memmove(objPtr->bytes + oldLength, bytes, numBytes);
+    }
     objPtr->bytes[newLength] = 0;
     objPtr->length = newLength;
 }
@@ -2658,6 +2663,38 @@ Tcl_ObjPrintf(
 /*
  *---------------------------------------------------------------------------
  *
+ * TclGetStringStorage --
+ *
+ *	Returns the string storage space of a Tcl_Obj.
+ *
+ * Results:
+ *	The pointer value objPtr->bytes is returned and the number of bytes
+ *	allocated there is written to *sizePtr (if known).
+ *
+ * Side effects:
+ *	May set objPtr->bytes.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+char *
+TclGetStringStorage(
+    Tcl_Obj *objPtr,
+    unsigned int *sizePtr)
+{
+    String *stringPtr;
+
+    if (objPtr->typePtr != &tclStringType || objPtr->bytes == NULL) {
+	return TclGetStringFromObj(objPtr, (int *)sizePtr);
+    }
+
+    stringPtr = GET_STRING(objPtr);
+    *sizePtr = stringPtr->allocated;
+    return objPtr->bytes;
+}
+/*
+ *---------------------------------------------------------------------------
+ *
  * TclStringObjReverse --
  *
  *	Implements the [string reverse] operation.
@@ -2848,7 +2885,11 @@ ExtendUnicodeRepWithString(
     }
 
     stringPtr->hasUnicode = 1;
-    stringPtr->numChars = needed;
+    if (bytes) {
+	stringPtr->numChars = needed;
+    } else {
+	numAppendChars = 0;
+    }
     for (dst=stringPtr->unicode + numOrigChars; numAppendChars-- > 0; dst++) {
 	bytes += TclUtfToUniChar(bytes, dst);
     }
diff --git a/generic/tclStubInit.c b/generic/tclStubInit.c
index e1918ef..7a84cba 100644
--- a/generic/tclStubInit.c
+++ b/generic/tclStubInit.c
@@ -44,6 +44,9 @@
 #define TclBackgroundException Tcl_BackgroundException
 #undef Tcl_SetIntObj
 #undef TclpInetNtoa
+#undef TclWinGetServByName
+#undef TclWinGetSockOpt
+#undef TclWinSetSockOpt
 
 /* See bug 510001: TclSockMinimumBuffers needs plat imp */
 #ifdef _WIN64
@@ -90,7 +93,7 @@ static unsigned short TclWinNToHS(unsigned short ns) {
 }
 #endif
 
-#ifdef __WIN32__
+#ifdef _WIN32
 #   define TclUnixWaitForFile 0
 #   define TclUnixCopyFile 0
 #   define TclUnixOpenTemporaryFile 0
@@ -111,7 +114,8 @@ TclpIsAtty(int fd)
     return isatty(fd);
 }
 
-int
+#define TclWinGetPlatformId winGetPlatformId
+static int
 TclWinGetPlatformId()
 {
     /* Don't bother to determine the real platform on cygwin,
@@ -127,27 +131,31 @@ void *TclWinGetTclInstance()
     return hInstance;
 }
 
-int
+#define TclWinSetSockOpt winSetSockOpt
+static int
 TclWinSetSockOpt(SOCKET s, int level, int optname,
 	    const char *optval, int optlen)
 {
     return setsockopt((int) s, level, optname, optval, optlen);
 }
 
-int
+#define TclWinGetSockOpt winGetSockOpt
+static int
 TclWinGetSockOpt(SOCKET s, int level, int optname,
 	    char *optval, int *optlen)
 {
     return getsockopt((int) s, level, optname, optval, optlen);
 }
 
-struct servent *
+#define TclWinGetServByName winGetServByName
+static struct servent *
 TclWinGetServByName(const char *name, const char *proto)
 {
     return getservbyname(name, proto);
 }
 
-char *
+#define TclWinNoBackslash winNoBackslash
+static char *
 TclWinNoBackslash(char *path)
 {
     char *p;
@@ -557,7 +565,7 @@ static const TclIntStubs tclIntStubs = {
 static const TclIntPlatStubs tclIntPlatStubs = {
     TCL_STUB_MAGIC,
     0,
-#if !defined(__WIN32__) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
     TclGetAndDetachPids, /* 0 */
     TclpCloseFile, /* 1 */
     TclpCreateCommandChannel, /* 2 */
@@ -590,7 +598,7 @@ static const TclIntPlatStubs tclIntPlatStubs = {
     TclWinCPUID, /* 29 */
     TclUnixOpenTemporaryFile, /* 30 */
 #endif /* UNIX */
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
     TclWinConvertError, /* 0 */
     TclWinConvertWSAError, /* 1 */
     TclWinGetServByName, /* 2 */
@@ -661,7 +669,7 @@ static const TclIntPlatStubs tclIntPlatStubs = {
 static const TclPlatStubs tclPlatStubs = {
     TCL_STUB_MAGIC,
     0,
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
     Tcl_WinUtfToTChar, /* 0 */
     Tcl_WinTCharToUtf, /* 1 */
 #endif /* WIN */
@@ -758,19 +766,19 @@ const TclStubs tclStubs = {
     Tcl_DbCkalloc, /* 6 */
     Tcl_DbCkfree, /* 7 */
     Tcl_DbCkrealloc, /* 8 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     Tcl_CreateFileHandler, /* 9 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     0, /* 9 */
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
     Tcl_CreateFileHandler, /* 9 */
 #endif /* MACOSX */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     Tcl_DeleteFileHandler, /* 10 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     0, /* 10 */
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
@@ -932,10 +940,10 @@ const TclStubs tclStubs = {
     Tcl_GetMaster, /* 164 */
     Tcl_GetNameOfExecutable, /* 165 */
     Tcl_GetObjResult, /* 166 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     Tcl_GetOpenFile, /* 167 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     0, /* 167 */
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
diff --git a/generic/tclTest.c b/generic/tclTest.c
index f121d0d..a27c95a 100644
--- a/generic/tclTest.c
+++ b/generic/tclTest.c
@@ -414,7 +414,7 @@ static int		TestNRELevels(ClientData clientData,
 static int		TestInterpResolverCmd(ClientData clientData,
 			    Tcl_Interp *interp, int objc,
 			    Tcl_Obj *const objv[]);
-#if defined(HAVE_CPUID) || defined(__WIN32__)
+#if defined(HAVE_CPUID) || defined(_WIN32)
 static int		TestcpuidCmd(ClientData dummy,
 			    Tcl_Interp* interp, int objc,
 			    Tcl_Obj *const objv[]);
@@ -681,7 +681,7 @@ Tcltest_Init(
 	    NULL, NULL);
     Tcl_CreateCommand(interp, "testexitmainloop", TestexitmainloopCmd,
 	    NULL, NULL);
-#if defined(HAVE_CPUID) || defined(__WIN32__)
+#if defined(HAVE_CPUID) || defined(_WIN32)
     Tcl_CreateObjCommand(interp, "testcpuid", TestcpuidCmd,
 	    (ClientData) 0, NULL);
 #endif
@@ -6648,7 +6648,7 @@ TestNumUtfCharsCmd(
     return TCL_OK;
 }
 
-#if defined(HAVE_CPUID) || defined(__WIN32__)
+#if defined(HAVE_CPUID) || defined(_WIN32)
 /*
  *----------------------------------------------------------------------
  *
diff --git a/generic/tclThread.c b/generic/tclThread.c
index d1f2691..8c972a8 100644
--- a/generic/tclThread.c
+++ b/generic/tclThread.c
@@ -339,8 +339,9 @@ Tcl_ConditionFinalize(
  *
  * TclFinalizeThreadData --
  *
- *	This function cleans up the thread-local storage. This is called once
- *	for each thread.
+ *	This function cleans up the thread-local storage. Secondary, it cleans
+ *	thread alloc cache.
+ *	This is called once for each thread before thread exits.
  *
  * Results:
  *	None.
@@ -355,6 +356,9 @@ void
 TclFinalizeThreadData(void)
 {
     TclFinalizeThreadDataThread();
+#if defined(TCL_THREADS) && defined(USE_THREAD_ALLOC)
+    TclFinalizeThreadAllocThread();
+#endif
 }
 
 /*
diff --git a/generic/tclThreadAlloc.c b/generic/tclThreadAlloc.c
index abd5af5..ddf888a 100644
--- a/generic/tclThreadAlloc.c
+++ b/generic/tclThreadAlloc.c
@@ -1023,6 +1023,33 @@ TclFinalizeThreadAlloc(void)
     TclpFreeAllocCache(NULL);
 }
 
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclFinalizeThreadAllocThread --
+ *
+ *	This procedure is used to destroy single thread private resources used
+ *	in this file. 
+ * Called in TclpFinalizeThreadData when a thread exits (Tcl_FinalizeThread).
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclFinalizeThreadAllocThread(void)
+{
+    Cache *cachePtr = TclpGetAllocCache();
+    if (cachePtr != NULL) {
+	TclpFreeAllocCache(cachePtr);
+    }
+}
+
 #else /* !(TCL_THREADS && USE_THREAD_ALLOC) */
 /*
  *----------------------------------------------------------------------
diff --git a/generic/tclThreadJoin.c b/generic/tclThreadJoin.c
index 4b09e1c..5c70a62 100644
--- a/generic/tclThreadJoin.c
+++ b/generic/tclThreadJoin.c
@@ -14,7 +14,7 @@
 
 #include "tclInt.h"
 
-#ifdef WIN32
+#ifdef _WIN32
 
 /*
  * The information about each joinable thread is remembered in a structure as
@@ -305,7 +305,7 @@ TclSignalExitThread(
 
     Tcl_MutexUnlock(&threadPtr->threadMutex);
 }
-#endif /* WIN32 */
+#endif /* _WIN32 */
 
 /*
  * Local Variables:
diff --git a/generic/tclUtil.c b/generic/tclUtil.c
index 2d00adf..ae3adae 100644
--- a/generic/tclUtil.c
+++ b/generic/tclUtil.c
@@ -111,7 +111,11 @@ static Tcl_HashTable *	GetThreadHash(Tcl_ThreadDataKey *keyPtr);
 static int		SetEndOffsetFromAny(Tcl_Interp *interp,
 			    Tcl_Obj *objPtr);
 static void		UpdateStringOfEndOffset(Tcl_Obj *objPtr);
-
+static int		FindElement(Tcl_Interp *interp, const char *string,
+			    int stringLength, const char *typeStr,
+			    const char *typeCode, const char **elementPtr,
+			    const char **nextPtr, int *sizePtr,
+			    int *literalPtr);
 /*
  * The following is the Tcl object type definition for an object that
  * represents a list index in the form, "end-offset". It is used as a
@@ -237,7 +241,7 @@ const Tcl_ObjType tclEndOffsetType = {
  *   of either braces or quotes to delimit it.
  *
  * This collection of parsing rules is implemented in the routine
- * TclFindElement().
+ * FindElement().
  *
  * In order to produce lists that can be parsed by these rules, we need the
  * ability to distinguish between characters that are part of a list element
@@ -505,9 +509,70 @@ TclFindElement(
 				 * does not/does require a call to 
 				 * TclCopyAndCollapse() by the caller. */
 {
-    const char *p = list;
+    return FindElement(interp, list, listLength, "list", "LIST", elementPtr,
+	    nextPtr, sizePtr, literalPtr);
+}
+
+int
+TclFindDictElement(
+    Tcl_Interp *interp,		/* Interpreter to use for error reporting. If
+				 * NULL, then no error message is left after
+				 * errors. */
+    const char *dict,		/* Points to the first byte of a string
+				 * containing a Tcl dictionary with zero or
+				 * more keys and values (possibly in
+				 * braces). */
+    int dictLength,		/* Number of bytes in the dict's string. */
+    const char **elementPtr,	/* Where to put address of first significant
+				 * character in the first element (i.e., key
+				 * or value) of dict. */
+    const char **nextPtr,	/* Fill in with location of character just
+				 * after all white space following end of
+				 * element (next arg or end of list). */
+    int *sizePtr,		/* If non-zero, fill in with size of
+				 * element. */
+    int *literalPtr)		/* If non-zero, fill in with non-zero/zero to
+				 * indicate that the substring of *sizePtr
+				 * bytes starting at **elementPtr is/is not
+				 * the literal key or value and therefore
+				 * does not/does require a call to 
+				 * TclCopyAndCollapse() by the caller. */
+{
+    return FindElement(interp, dict, dictLength, "dict", "DICTIONARY",
+	    elementPtr, nextPtr, sizePtr, literalPtr);
+}
+
+static int
+FindElement(
+    Tcl_Interp *interp,		/* Interpreter to use for error reporting. If
+				 * NULL, then no error message is left after
+				 * errors. */
+    const char *string,		/* Points to the first byte of a string
+				 * containing a Tcl list or dictionary with
+				 * zero or more elements (possibly in
+				 * braces). */
+    int stringLength,		/* Number of bytes in the string. */
+    const char *typeStr,	/* The name of the type of thing we are
+				 * parsing, for error messages. */
+    const char *typeCode,	/* The type code for thing we are parsing, for
+				 * error messages. */
+    const char **elementPtr,	/* Where to put address of first significant
+				 * character in first element. */
+    const char **nextPtr,	/* Fill in with location of character just
+				 * after all white space following end of
+				 * argument (next arg or end of list/dict). */
+    int *sizePtr,		/* If non-zero, fill in with size of
+				 * element. */
+    int *literalPtr)		/* If non-zero, fill in with non-zero/zero to
+				 * indicate that the substring of *sizePtr
+				 * bytes starting at **elementPtr is/is not
+				 * the literal list/dict element and therefore
+				 * does not/does require a call to 
+				 * TclCopyAndCollapse() by the caller. */
+{
+    const char *p = string;
     const char *elemStart;	/* Points to first byte of first element. */
-    const char *limit;		/* Points just after list's last byte. */
+    const char *limit;		/* Points just after list/dict's last byte. */
     int openBraces = 0;		/* Brace nesting level during parse. */
     int inQuotes = 0;
     int size = 0;		/* lint. */
@@ -517,11 +582,11 @@ TclFindElement(
 
     /*
      * Skim off leading white space and check for an opening brace or quote.
-     * We treat embedded NULLs in the list as bytes belonging to a list
-     * element.
+     * We treat embedded NULLs in the list/dict as bytes belonging to a list 
+     * element (or dictionary key or value).
      */
 
-    limit = (list + listLength);
+    limit = (string + stringLength);
     while ((p < limit) && (TclIsSpaceProc(*p))) {
 	p++;
     }
@@ -582,9 +647,9 @@ TclFindElement(
 			p2++;
 		    }
 		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
-			    "list element in braces followed by \"%.*s\" "
-			    "instead of space", (int) (p2-p), p));
-		    Tcl_SetErrorCode(interp, "TCL", "VALUE", "LIST", "JUNK",
+			    "%s element in braces followed by \"%.*s\" "
+			    "instead of space", typeStr, (int) (p2-p), p));
+		    Tcl_SetErrorCode(interp, "TCL", "VALUE", typeCode, "JUNK",
 			    NULL);
 		}
 		return TCL_ERROR;
@@ -651,9 +716,9 @@ TclFindElement(
 			p2++;
 		    }
 		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
-			    "list element in quotes followed by \"%.*s\" "
-			    "instead of space", (int) (p2-p), p));
-		    Tcl_SetErrorCode(interp, "TCL", "VALUE", "LIST", "JUNK",
+			    "%s element in quotes followed by \"%.*s\" "
+			    "instead of space", typeStr, (int) (p2-p), p));
+		    Tcl_SetErrorCode(interp, "TCL", "VALUE", typeCode, "JUNK",
 			    NULL);
 		}
 		return TCL_ERROR;
@@ -664,23 +729,23 @@ TclFindElement(
     }
 
     /*
-     * End of list: terminate element.
+     * End of list/dict: terminate element.
      */
 
     if (p == limit) {
 	if (openBraces != 0) {
 	    if (interp != NULL) {
-		Tcl_SetObjResult(interp, Tcl_NewStringObj(
-			"unmatched open brace in list", -1));
-		Tcl_SetErrorCode(interp, "TCL", "VALUE", "LIST", "BRACE",
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"unmatched open brace in %s", typeStr));
+		Tcl_SetErrorCode(interp, "TCL", "VALUE", typeCode, "BRACE",
 			NULL);
 	    }
 	    return TCL_ERROR;
 	} else if (inQuotes) {
 	    if (interp != NULL) {
-		Tcl_SetObjResult(interp, Tcl_NewStringObj(
-			"unmatched open quote in list", -1));
-		Tcl_SetErrorCode(interp, "TCL", "VALUE", "LIST", "QUOTE",
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"unmatched open quote in %s", typeStr));
+		Tcl_SetErrorCode(interp, "TCL", "VALUE", typeCode, "QUOTE",
 			NULL);
 	    }
 	    return TCL_ERROR;
diff --git a/generic/tclZlib.c b/generic/tclZlib.c
index 9bceb4c..2e27303 100644
--- a/generic/tclZlib.c
+++ b/generic/tclZlib.c
@@ -2994,47 +2994,18 @@ ZlibTransformInput(
 	 */
 
 	if (readBytes < 0) {
-	    /*
-	     * Report errors to caller. The state of the seek system is
-	     * unchanged!
-	     */
-
-	    if ((Tcl_GetErrno() == EAGAIN) && (gotBytes > 0)) {
-		/*
-		 * EAGAIN is a special situation. If we had some data before
-		 * we report that instead of the request to re-try.
-		 */
 
+	    /* See ReflectInput() in tclIORTrans.c */
+	    if (Tcl_InputBlocked(cd->parent) && (gotBytes > 0)) {
 		return gotBytes;
 	    }
 
 	    *errorCodePtr = Tcl_GetErrno();
 	    return -1;
-	} else if (readBytes == 0) {
-	    /*
-	     * Check wether we hit on EOF in 'parent' or not. If not,
-	     * differentiate between blocking and non-blocking modes. In
-	     * non-blocking mode we ran temporarily out of data. Signal this
-	     * to the caller via EWOULDBLOCK and error return (-1). In the
-	     * other cases we simply return what we got and let the caller
-	     * wait for more. On the other hand, if we got an EOF we have to
-	     * convert and flush all waiting partial data.
-	     */
-
-	    if (!Tcl_Eof(cd->parent)) {
-		/*
-		 * The state of the seek system is unchanged!
-		 */
-
-		if ((gotBytes == 0) && (cd->flags & ASYNC)) {
-		    *errorCodePtr = EWOULDBLOCK;
-		    return -1;
-		}
-		return gotBytes;
-	    }
-
+	}
+	if (readBytes == 0) {
 	    /*
-	     * (Semi-)Eof in parent.
+	     * Eof in parent.
 	     *
 	     * Now this is a bit different. The partial data waiting is
 	     * converted and returned.
@@ -3052,12 +3023,6 @@ ZlibTransformInput(
 
 		return gotBytes;
 	    }
-
-	    /*
-	     * Reset eof, force caller to drain result buffer.
-	     */
-
-	    ((Channel *) cd->parent)->state->flags &= ~CHANNEL_EOF;
 	} else /* readBytes > 0 */ {
 	    /*
 	     * Transform the read chunk, which was not empty. Anything we get