merge core-8-5-branch

38 files changed, 2195 insertions, 1664 deletions

diff --git a/doc/clock.n b/doc/clock.n
index 7c4c3df..a0cc63e 100644
--- a/doc/clock.n
+++ b/doc/clock.n
@@ -626,8 +626,9 @@ On output, produces a locale-dependent time of day representation on a
 12-hour clock. On input, accepts whatever \fB%r\fR produces.
 .TP
 \fB%R\fR
-On output, produces a locale-dependent time of day representation on a
-24-hour clock. On input, accepts whatever \fB%R\fR produces.
+On output, the time in 24-hour notation (%H:%M). For a version
+including the seconds, see \fB%T\fR below. On input, accepts whatever
+\fB%R\fR produces.
 .TP
 \fB%s\fR
 On output, simply formats the \fItimeVal\fR argument as a decimal
diff --git a/doc/tclvars.n b/doc/tclvars.n
index b3e1bee..84823e0 100644
--- a/doc/tclvars.n
+++ b/doc/tclvars.n
@@ -284,8 +284,8 @@ was compiled with threads enabled.
 \fBuser\fR
 This identifies the
 current user based on the login information available on the platform.
-This comes from the USER or LOGNAME environment variable on Unix,
-and the value from GetUserName on Windows.
+This value comes from the getuid() and getpwuid() system calls on Unix,
+and the value from the GetUserName() system call on Windows.
 .TP
 \fBwordSize\fR
 This gives the size of the native-machine word in bytes (strictly, it
diff --git a/generic/tclBinary.c b/generic/tclBinary.c
index dbb296b..68289f2 100644
--- a/generic/tclBinary.c
+++ b/generic/tclBinary.c
@@ -549,6 +549,98 @@ UpdateStringOfByteArray(
 /*
  *----------------------------------------------------------------------
  *
+ * TclAppendBytesToByteArray --
+ *
+ *	This function appends an array of bytes to a byte array object. Note
+ *	that the object *must* be unshared, and the array of bytes *must not*
+ *	refer to the object being appended to.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Allocates enough memory for an array of bytes of the requested total
+ *	size, or possibly larger. [Bug 2992970]
+ *
+ *----------------------------------------------------------------------
+ */
+
+#define TCL_MIN_GROWTH 1024
+void
+TclAppendBytesToByteArray(
+    Tcl_Obj *objPtr,
+    const unsigned char *bytes,
+    int len)
+{
+    ByteArray *byteArrayPtr;
+    int needed;
+
+    if (Tcl_IsShared(objPtr)) {
+	Tcl_Panic("%s called with shared object","TclAppendBytesToByteArray");
+    }
+    if (len < 0) {
+	Tcl_Panic("%s must be called with definite number of bytes to append",
+		"TclAppendBytesToByteArray");
+    }
+    if (len == 0) {
+	/* Append zero bytes is a no-op. */
+	return;
+    }
+    if (objPtr->typePtr != &tclByteArrayType) {
+	SetByteArrayFromAny(NULL, objPtr);
+    }
+    byteArrayPtr = GET_BYTEARRAY(objPtr);
+
+    if (len > INT_MAX - byteArrayPtr->used) {
+	Tcl_Panic("max size for a Tcl value (%d bytes) exceeded", INT_MAX);
+    }
+
+    needed = byteArrayPtr->used + len;
+    /*
+     * If we need to, resize the allocated space in the byte array.
+     */
+
+    if (needed > byteArrayPtr->allocated) {
+	ByteArray *ptr = NULL;
+	int attempt;
+
+	if (needed <= INT_MAX/2) {
+	    /* Try to allocate double the total space that is needed. */
+	    attempt = 2 * needed;
+	    ptr = (ByteArray *) attemptckrealloc((void *) byteArrayPtr,
+		    BYTEARRAY_SIZE(attempt));
+	}
+	if (ptr == NULL) {
+	    /* Try to allocate double the increment that is needed (plus). */
+	    unsigned int limit = INT_MAX - needed;
+	    unsigned int extra = len + TCL_MIN_GROWTH;
+	    int growth = (int) ((extra > limit) ? limit : extra);
+
+	    attempt = needed + growth;
+	    ptr = (ByteArray *) attemptckrealloc((void *) byteArrayPtr,
+		    BYTEARRAY_SIZE(attempt));
+	}
+	if (ptr == NULL) {
+	    /* Last chance: Try to allocate exactly what is needed. */
+	    attempt = needed;
+	    ptr = (ByteArray *) ckrealloc((void *)byteArrayPtr,
+		    BYTEARRAY_SIZE(attempt));
+	}
+	byteArrayPtr = ptr;
+	byteArrayPtr->allocated = attempt;
+	SET_BYTEARRAY(objPtr, byteArrayPtr);
+    }
+
+    if (bytes) {
+	memcpy(byteArrayPtr->bytes + byteArrayPtr->used, bytes, len);
+    }
+    byteArrayPtr->used += len;
+    TclInvalidateStringRep(objPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * Tcl_BinaryObjCmd --
  *
  *	This procedure implements the "binary" Tcl command.
diff --git a/generic/tclClock.c b/generic/tclClock.c
index 5b95ae6..3ec94fb 100644
--- a/generic/tclClock.c
+++ b/generic/tclClock.c
@@ -548,19 +548,22 @@ 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;
@@ -639,21 +642,21 @@ 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;
diff --git a/generic/tclCmdMZ.c b/generic/tclCmdMZ.c
index 6fd468c..70943e9 100644
--- a/generic/tclCmdMZ.c
+++ b/generic/tclCmdMZ.c
@@ -1345,7 +1345,7 @@ StringIndexCmd(
      * Unicode string rep to get the index'th char.
      */
 
-    if (objv[1]->typePtr == &tclByteArrayType) {
+    if (TclIsPureByteArray(objv[1])) {
 	const unsigned char *string =
 		Tcl_GetByteArrayFromObj(objv[1], &length);
 
@@ -2086,7 +2086,7 @@ StringRangeCmd(
      * Unicode string rep to get the range.
      */
 
-    if (objv[1]->typePtr == &tclByteArrayType) {
+    if (TclIsPureByteArray(objv[1])) {
 	string = Tcl_GetByteArrayFromObj(objv[1], &length);
 	length--;
     } else {
@@ -2537,8 +2537,8 @@ StringEqualCmd(
 	return TCL_OK;
     }
 
-    if (!nocase && objv[0]->typePtr == &tclByteArrayType &&
-	    objv[1]->typePtr == &tclByteArrayType) {
+    if (!nocase && TclIsPureByteArray(objv[0]) &&
+	    TclIsPureByteArray(objv[1])) {
 	/*
 	 * Use binary versions of comparisons since that won't cause undue
 	 * type conversions and it is much faster. Only do this if we're
@@ -2684,8 +2684,8 @@ StringCmpCmd(
 	return TCL_OK;
     }
 
-    if (!nocase && objv[0]->typePtr == &tclByteArrayType &&
-	    objv[1]->typePtr == &tclByteArrayType) {
+    if (!nocase && TclIsPureByteArray(objv[0]) &&
+	    TclIsPureByteArray(objv[1])) {
 	/*
 	 * Use binary versions of comparisons since that won't cause undue
 	 * type conversions and it is much faster. Only do this if we're
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 2e396e8..c4f9836 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -4235,8 +4235,8 @@ TclExecuteByteCode(
 	     */
 
 	    iResult = s1len = s2len = 0;
-	} else if ((valuePtr->typePtr == &tclByteArrayType)
-		&& (value2Ptr->typePtr == &tclByteArrayType)) {
+	} else if (TclIsPureByteArray(valuePtr)
+		&& TclIsPureByteArray(value2Ptr)) {
 	    s1 = (char *) Tcl_GetByteArrayFromObj(valuePtr, &s1len);
 	    s2 = (char *) Tcl_GetByteArrayFromObj(value2Ptr, &s2len);
 	    iResult = memcmp(s1, s2,
@@ -4354,7 +4354,7 @@ TclExecuteByteCode(
 	 * use the Unicode string rep to get the index'th char.
 	 */
 
-	if (valuePtr->typePtr == &tclByteArrayType) {
+	if (TclIsPureByteArray(valuePtr)) {
 	    bytes = (char *)Tcl_GetByteArrayFromObj(valuePtr, &length);
 	} else {
 	    /*
@@ -4370,7 +4370,7 @@ TclExecuteByteCode(
 	}
 
 	if ((index >= 0) && (index < length)) {
-	    if (valuePtr->typePtr == &tclByteArrayType) {
+	    if (TclIsPureByteArray(valuePtr)) {
 		objResultPtr = Tcl_NewByteArrayObj((unsigned char *)
 			(&bytes[index]), 1);
 	    } else if (valuePtr->bytes && length == valuePtr->length) {
@@ -4422,7 +4422,7 @@ TclExecuteByteCode(
 	    ustring2 = Tcl_GetUnicodeFromObj(value2Ptr, &length2);
 	    match = TclUniCharMatch(ustring1, length1, ustring2, length2,
 		    nocase);
-	} else if ((valuePtr->typePtr == &tclByteArrayType) && !nocase) {
+	} else if (TclIsPureByteArray(valuePtr) && !nocase) {
 	    unsigned char *string1, *string2;
 	    int length1, length2;
 
diff --git a/generic/tclIO.c b/generic/tclIO.c
index 3636861..0716074 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,
@@ -173,8 +178,6 @@ static void		CleanupChannelHandlers(Tcl_Interp *interp,
 static int		CloseChannel(Tcl_Interp *interp, Channel *chanPtr,
 			    int errorCode);
 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);
@@ -188,7 +191,7 @@ 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);
+static int		DoRead(Channel *chanPtr, char *dst, int bytesToRead);
 static int		DoReadChars(Channel *chan, Tcl_Obj *objPtr, int toRead,
 			    int appendFlag);
 static int		FilterInputBytes(Channel *chanPtr,
@@ -205,16 +208,16 @@ 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,
@@ -281,7 +284,7 @@ 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)
 
@@ -295,6 +298,7 @@ static int WillRead(Channel *chanPtr);
 
 #define SetFlag(statePtr, flag)		((statePtr)->flags |= (flag))
 #define ResetFlag(statePtr, flag)	((statePtr)->flags &= ~(flag))
+#define GotFlag(statePtr, flag)		((statePtr)->flags & (flag))
 
 /*
  * Macro for testing whether a string (in optionName, length len) matches a
@@ -342,21 +346,78 @@ static Tcl_ObjType chanObjType = {
 #define MAX_CHANNEL_BUFFER_SIZE (1024*1024)
 
 /*
- * ChanRead, dropped here by a time traveler, see 8.6
+ *---------------------------------------------------------------------------
+ *
+ * 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 inline int
+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
@@ -459,7 +520,7 @@ TclFinalizeIOSubsystem(void)
 		statePtr != NULL;
 		statePtr = statePtr->nextCSPtr) {
 	    chanPtr = statePtr->topChanPtr;
-	    if (!(statePtr->flags & (CHANNEL_INCLOSE|CHANNEL_CLOSED|CHANNEL_DEAD))) {
+	    if (!GotFlag(statePtr, CHANNEL_INCLOSE|CHANNEL_CLOSED|CHANNEL_DEAD)) {
 		active = 1;
 		break;
 	    }
@@ -556,6 +617,7 @@ Tcl_SetStdChannel(
     int type)			/* One of TCL_STDIN, TCL_STDOUT, TCL_STDERR. */
 {
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
     switch (type) {
     case TCL_STDIN:
 	tsdPtr->stdinInitialized = 1;
@@ -672,11 +734,9 @@ Tcl_CreateCloseHandler(
     ClientData clientData)	/* Arbitrary data to pass to the close
 				 * callback. */
 {
-    ChannelState *statePtr;
+    ChannelState *statePtr = ((Channel *) chan)->state;
     CloseCallback *cbPtr;
 
-    statePtr = ((Channel *) chan)->state;
-
     cbPtr = (CloseCallback *) ckalloc(sizeof(CloseCallback));
     cbPtr->proc = proc;
     cbPtr->clientData = clientData;
@@ -712,10 +772,9 @@ Tcl_DeleteCloseHandler(
     ClientData clientData)	/* The callback data for the callback to
 				 * remove. */
 {
-    ChannelState *statePtr;
+    ChannelState *statePtr = ((Channel *) chan)->state;
     CloseCallback *cbPtr, *cbPrevPtr;
 
-    statePtr = ((Channel *) chan)->state;
     for (cbPtr = statePtr->closeCbPtr, cbPrevPtr = NULL;
 	    cbPtr != NULL; cbPtr = cbPtr->nextPtr) {
 	if ((cbPtr->proc == proc) && (cbPtr->clientData == clientData)) {
@@ -869,7 +928,7 @@ DeleteChannelTable(
 	SetFlag(statePtr, CHANNEL_TAINTED);
 	statePtr->refCount--;
 	if (statePtr->refCount <= 0) {
-	    if (!(statePtr->flags & BG_FLUSH_SCHEDULED)) {
+	    if (!GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 		(void) Tcl_Close(interp, (Tcl_Channel) chanPtr);
 	    }
 	}
@@ -1060,7 +1119,7 @@ Tcl_UnregisterChannel(
 
     statePtr = ((Channel *) chan)->state->bottomChanPtr->state;
 
-    if (statePtr->flags & CHANNEL_INCLOSE) {
+    if (GotFlag(statePtr, CHANNEL_INCLOSE)) {
 	if (interp != NULL) {
 	    Tcl_AppendResult(interp, "Illegal recursive call to close "
 		    "through close-handler of channel", NULL);
@@ -1089,22 +1148,13 @@ 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((ClientData)statePtr);
-	if (!(statePtr->flags & BG_FLUSH_SCHEDULED)) {
+	if (!GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	    /*
 	     * We don't want to re-enter Tcl_Close().
 	     */
 
-	    if (!(statePtr->flags & CHANNEL_CLOSED)) {
+	    if (!GotFlag(statePtr, CHANNEL_CLOSED)) {
 		if (Tcl_Close(interp, chan) != TCL_OK) {
 		    SetFlag(statePtr, CHANNEL_CLOSED);
 		    Tcl_Release((ClientData)statePtr);
@@ -1313,7 +1363,7 @@ Tcl_GetChannel(
     chanPtr = Tcl_GetHashValue(hPtr);
     chanPtr = chanPtr->state->bottomChanPtr;
     if (modePtr != NULL) {
-	*modePtr = (chanPtr->state->flags & (TCL_READABLE|TCL_WRITABLE));
+	*modePtr = GotFlag(chanPtr->state, TCL_READABLE|TCL_WRITABLE);
     }
 
     return (Tcl_Channel) chanPtr;
@@ -1361,7 +1411,7 @@ TclGetChannelFromObj(
     *channelPtr = (Tcl_Channel) (statePtr->bottomChanPtr);
 
     if (modePtr != NULL) {
-	*modePtr = (statePtr->flags & (TCL_READABLE|TCL_WRITABLE));
+	*modePtr = GotFlag(statePtr, TCL_READABLE|TCL_WRITABLE);
     }
 
     return TCL_OK;
@@ -1624,7 +1674,7 @@ Tcl_StackChannel(
      *	--+---+---+---+----+
      */
 
-    if ((mask & (statePtr->flags & (TCL_READABLE | TCL_WRITABLE))) == 0) {
+    if ((mask & (GotFlag(statePtr, TCL_READABLE | TCL_WRITABLE))) == 0) {
 	if (interp) {
 	    Tcl_AppendResult(interp,
 		    "reading and writing both disallowed for channel \"",
@@ -1641,15 +1691,16 @@ Tcl_StackChannel(
      */
 
     if ((mask & TCL_WRITABLE) != 0) {
-        CopyState *csPtrR;
-        CopyState *csPtrW;
+	CopyState *csPtrR = statePtr->csPtrR;
+	CopyState *csPtrW = statePtr->csPtrW;
 
-        csPtrR           = statePtr->csPtrR;
 	statePtr->csPtrR = NULL;
-
-        csPtrW           = statePtr->csPtrW;
 	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;
@@ -1680,17 +1731,17 @@ 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;
@@ -1782,6 +1833,13 @@ Tcl_UnstackChannel(
 	 * 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;
 
 	/*
@@ -1792,14 +1850,11 @@ Tcl_UnstackChannel(
 	 * CheckForChannelErrors inside.
 	 */
 
-	if (statePtr->flags & TCL_WRITABLE) {
-	    CopyState *csPtrR;
-	    CopyState *csPtrW;
+	if (GotFlag(statePtr, TCL_WRITABLE)) {
+	    CopyState *csPtrR = statePtr->csPtrR;
+	    CopyState *csPtrW = statePtr->csPtrW;
 
-	    csPtrR           = statePtr->csPtrR;
 	    statePtr->csPtrR = NULL;
-
-	    csPtrW           = statePtr->csPtrW;
 	    statePtr->csPtrW = NULL;
 
 	    if (Tcl_Flush((Tcl_Channel) chanPtr) != TCL_OK) {
@@ -1836,16 +1891,14 @@ Tcl_UnstackChannel(
 	 * 'DiscardInputQueued' on that.
 	 */
 
-	if ((((statePtr->flags & TCL_READABLE) != 0)) &&
+	if (GotFlag(statePtr, TCL_READABLE) &&
 		((statePtr->inQueueHead != NULL) ||
 		(chanPtr->inQueueHead != NULL))) {
-
 	    if ((statePtr->inQueueHead != NULL) &&
 		    (chanPtr->inQueueHead != NULL)) {
 		statePtr->inQueueTail->nextPtr = chanPtr->inQueueHead;
 		statePtr->inQueueTail = chanPtr->inQueueTail;
 		statePtr->inQueueHead = statePtr->inQueueTail;
-
 	    } else if (chanPtr->inQueueHead != NULL) {
 		statePtr->inQueueHead = chanPtr->inQueueHead;
 		statePtr->inQueueTail = chanPtr->inQueueTail;
@@ -1902,7 +1955,7 @@ Tcl_UnstackChannel(
 	 */
 
 	Tcl_EventuallyFree(chanPtr, TCL_DYNAMIC);
-	UpdateInterest(downChanPtr);
+	UpdateInterest(statePtr->topChanPtr);
 
 	if (result != 0) {
 	    Tcl_SetErrno(result);
@@ -2105,7 +2158,7 @@ Tcl_GetChannelMode(
     ChannelState *statePtr = ((Channel *) chan)->state;
 				/* State of actual channel. */
 
-    return (statePtr->flags & (TCL_READABLE | TCL_WRITABLE));
+    return GotFlag(statePtr, TCL_READABLE | TCL_WRITABLE);
 }
 
 /*
@@ -2216,8 +2269,33 @@ AllocChannelBuffer(
     bufPtr->nextRemoved	= BUFFER_PADDING;
     bufPtr->bufLength	= length + BUFFER_PADDING;
     bufPtr->nextPtr	= NULL;
+    bufPtr->refCount	= 1;
     return bufPtr;
 }
+
+static void
+PreserveChannelBuffer(
+    ChannelBuffer *bufPtr)
+{
+    bufPtr->refCount++;
+}
+
+static void
+ReleaseChannelBuffer(
+    ChannelBuffer *bufPtr)
+{
+    if (--bufPtr->refCount) {
+	return;
+    }
+    ckfree((char *) bufPtr);
+}
+
+static int
+IsShared(
+    ChannelBuffer *bufPtr)
+{
+    return bufPtr->refCount > 1;
+}
 
 /*
  *----------------------------------------------------------------------
@@ -2248,20 +2326,23 @@ RecycleBuffer(
     /*
      * Do we have to free the buffer to the OS?
      */
+    if (IsShared(bufPtr)) {
+	mustDiscard = 1;
+    }
 
     if (mustDiscard) {
-	ckfree((char *) 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((char *) bufPtr);
+    if ((bufPtr->bufLength - BUFFER_PADDING) != statePtr->bufSize) {
+	ReleaseChannelBuffer(bufPtr);
 	return;
     }
 
@@ -2269,7 +2350,7 @@ RecycleBuffer(
      * Only save buffers for the input queue if the channel is readable.
      */
 
-    if (statePtr->flags & TCL_READABLE) {
+    if (GotFlag(statePtr, TCL_READABLE)) {
 	if (statePtr->inQueueHead == NULL) {
 	    statePtr->inQueueHead = bufPtr;
 	    statePtr->inQueueTail = bufPtr;
@@ -2285,7 +2366,7 @@ RecycleBuffer(
      * Only save buffers for the output queue if the channel is writable.
      */
 
-    if (statePtr->flags & TCL_WRITABLE) {
+    if (GotFlag(statePtr, TCL_WRITABLE)) {
 	if (statePtr->curOutPtr == NULL) {
 	    statePtr->curOutPtr = bufPtr;
 	    goto keepBuffer;
@@ -2296,7 +2377,7 @@ RecycleBuffer(
      * If we reached this code we return the buffer to the OS.
      */
 
-    ckfree((char *) bufPtr);
+    ReleaseChannelBuffer(bufPtr);
     return;
 
   keepBuffer:
@@ -2358,7 +2439,7 @@ CheckForDeadChannel(
     Tcl_Interp *interp,		/* For error reporting (can be NULL) */
     ChannelState *statePtr)	/* The channel state to check. */
 {
-    if (statePtr->flags & CHANNEL_DEAD) {
+    if (GotFlag(statePtr, CHANNEL_DEAD)) {
 	Tcl_SetErrno(EINVAL);
 	if (interp) {
 	    Tcl_AppendResult(interp,
@@ -2400,8 +2481,6 @@ 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
@@ -2421,62 +2500,57 @@ 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.
      */
 
-    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))
-		|| ((statePtr->flags & 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) &&
-		(statePtr->flags & BG_FLUSH_SCHEDULED)) {
-	    return 0;
-	}
+    /*
+     * 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.
+     */
+
+    while (statePtr->outQueueHead) {
+	bufPtr = statePtr->outQueueHead;
 
 	/*
 	 * Produce the output on the channel.
 	 */
 
-	toWrite = BytesLeft(bufPtr);
-	if (toWrite == 0) {
-	    written = 0;
-	} else {
-	    written = (chanPtr->typePtr->outputProc)(chanPtr->instanceData,
-		RemovePoint(bufPtr), toWrite, &errorCode);
-	}
+	PreserveChannelBuffer(bufPtr);
+	written = (chanPtr->typePtr->outputProc)(chanPtr->instanceData,
+		RemovePoint(bufPtr), BytesLeft(bufPtr), &errorCode);
 
 	/*
 	 * If the write failed completely attempt to start the asynchronous
@@ -2491,6 +2565,7 @@ FlushChannel(
 
 	    if (errorCode == EINTR) {
 		errorCode = 0;
+		ReleaseChannelBuffer(bufPtr);
 		continue;
 	    }
 
@@ -2507,11 +2582,12 @@ FlushChannel(
 		 * it's a tty channel (dup'ed underneath)
 		 */
 
-		if (!(statePtr->flags & BG_FLUSH_SCHEDULED)) {
+		if (!GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 		    SetFlag(statePtr, BG_FLUSH_SCHEDULED);
 		    UpdateInterest(chanPtr);
 		}
 		errorCode = 0;
+		ReleaseChannelBuffer(bufPtr);
 		break;
 	    }
 
@@ -2579,8 +2655,11 @@ 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;
 	}
 
@@ -2597,7 +2676,8 @@ 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.
@@ -2606,13 +2686,19 @@ FlushChannel(
      * data has been flushed at the system level.
      */
 
-    if (statePtr->flags & BG_FLUSH_SCHEDULED) {
+    if (GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	if (wroteSome) {
 	    return errorCode;
 	} else if (statePtr->outQueueHead == NULL) {
 	    ResetFlag(statePtr, BG_FLUSH_SCHEDULED);
 	    (chanPtr->typePtr->watchProc)(chanPtr->instanceData,
 		    statePtr->interestMask);
+	} else {
+	    /* TODO: If code reaches this point, it means a writable
+	     * event is being handled on the channel, but the channel
+	     * could not in fact be written to.  This ought not happen,
+	     * but Unix pipes appear to act this way (see io-53.4).
+	     * Also can imagine broken reflected channels. */
 	}
     }
 
@@ -2622,7 +2708,7 @@ FlushChannel(
      * current output buffer.
      */
 
-    if ((statePtr->flags & CHANNEL_CLOSED) && (statePtr->refCount <= 0) &&
+    if (GotFlag(statePtr, CHANNEL_CLOSED) && (statePtr->refCount <= 0) &&
 	    (statePtr->outQueueHead == NULL) &&
 	    ((statePtr->curOutPtr == NULL) ||
 	    IsBufferEmpty(statePtr->curOutPtr))) {
@@ -2681,7 +2767,7 @@ CloseChannel(
      */
 
     if (statePtr->curOutPtr != NULL) {
-	ckfree((char *) statePtr->curOutPtr);
+	ReleaseChannelBuffer(statePtr->curOutPtr);
 	statePtr->curOutPtr = NULL;
     }
 
@@ -2698,7 +2784,7 @@ CloseChannel(
      * device.
      */
 
-    if ((statePtr->outEofChar != 0) && (statePtr->flags & TCL_WRITABLE)) {
+    if ((statePtr->outEofChar != 0) && GotFlag(statePtr, TCL_WRITABLE)) {
 	int dummy;
 	char c = (char) statePtr->outEofChar;
 
@@ -3103,7 +3189,7 @@ Tcl_Close(
 	Tcl_Panic("called Tcl_Close on channel with refCount > 0");
     }
 
-    if (statePtr->flags & CHANNEL_INCLOSE) {
+    if (GotFlag(statePtr, CHANNEL_INCLOSE)) {
 	if (interp) {
 	    Tcl_AppendResult(interp, "Illegal recursive call to close "
 		    "through close-handler of channel", NULL);
@@ -3119,7 +3205,8 @@ Tcl_Close(
 
     stickyError = 0;
 
-    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;
 	if (WriteChars(chanPtr, "", 0) < 0) {
@@ -3157,14 +3244,6 @@ 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.
      */
@@ -3209,7 +3288,17 @@ 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;
@@ -3556,12 +3645,25 @@ static void WillWrite(Channel *chanPtr)
 
 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;
         }
@@ -3612,7 +3714,7 @@ Write(
 
     endEncoding = ((statePtr->outputEncodingFlags & TCL_ENCODING_END) != 0);
 
-    if ((statePtr->flags & CHANNEL_LINEBUFFERED)
+    if (GotFlag(statePtr, CHANNEL_LINEBUFFERED)
 	    || (statePtr->outputTranslation != TCL_TRANSLATE_LF)) {
 	nextNewLine = memchr(src, '\n', srcLen);
     }
@@ -3642,6 +3744,7 @@ Write(
 	    bufPtr->nextAdded += saved;
 	    saved = 0;
 	}
+	PreserveChannelBuffer(bufPtr);
 	dst = InsertPoint(bufPtr);
 	dstLen = SpaceLeft(bufPtr);
 
@@ -3655,6 +3758,7 @@ 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;
@@ -3697,9 +3801,7 @@ 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++;
@@ -3731,6 +3833,7 @@ Write(
 
 	if (IsBufferFull(bufPtr)) {
 	    if (FlushChannel(NULL, chanPtr, 0) != 0) {
+		ReleaseChannelBuffer(bufPtr);
 		return -1;
 	    }
 	    flushed += statePtr->bufSize;
@@ -3738,10 +3841,10 @@ Write(
 		needNlFlush = 0;
 	    }
 	}
+	ReleaseChannelBuffer(bufPtr);
     }
-    if ((flushed < total) && (statePtr->flags & CHANNEL_UNBUFFERED ||
-	    (needNlFlush && statePtr->flags & CHANNEL_LINEBUFFERED))) {
-	SetFlag(statePtr, BUFFER_READY);
+    if ((flushed < total) && (GotFlag(statePtr, CHANNEL_UNBUFFERED) ||
+	    (needNlFlush && GotFlag(statePtr, CHANNEL_LINEBUFFERED)))) {
 	if (FlushChannel(NULL, chanPtr, 0) != 0) {
 	    return -1;
 	}
@@ -3852,6 +3955,7 @@ Tcl_GetsObj(
      */
 
     chanPtr = statePtr->topChanPtr;
+    Tcl_Preserve(chanPtr);
 
     bufPtr = statePtr->inQueueHead;
     encoding = statePtr->encoding;
@@ -3984,7 +4088,7 @@ Tcl_GetsObj(
 	case TCL_TRANSLATE_AUTO:
 	    eol = dst;
 	    skip = 1;
-	    if (statePtr->flags & INPUT_SAW_CR) {
+	    if (GotFlag(statePtr, INPUT_SAW_CR)) {
 		ResetFlag(statePtr, INPUT_SAW_CR);
 		if ((eol < dstEnd) && (*eol == '\n')) {
 		    /*
@@ -4052,7 +4156,7 @@ Tcl_GetsObj(
 	    SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF);
 	    statePtr->inputEncodingFlags |= TCL_ENCODING_END;
 	}
-	if (statePtr->flags & CHANNEL_EOF) {
+	if (GotFlag(statePtr, CHANNEL_EOF)) {
 	    skip = 0;
 	    eol = dstEnd;
 	    if (eol == objPtr->bytes + oldLength) {
@@ -4064,6 +4168,7 @@ Tcl_GetsObj(
 		Tcl_SetObjLength(objPtr, oldLength);
 		CommonGetsCleanup(chanPtr);
 		copiedTotal = -1;
+		ResetFlag(statePtr, CHANNEL_BLOCKED);
 		goto done;
 	    }
 	    goto gotEOL;
@@ -4080,6 +4185,17 @@ Tcl_GetsObj(
      */
 
   gotEOL:
+    /*
+     * 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);
+    }
+
     bufPtr = gs.bufPtr;
     if (bufPtr == NULL) {
 	Tcl_Panic("Tcl_GetsObj: gotEOL reached with bufPtr==NULL");
@@ -4108,13 +4224,22 @@ Tcl_GetsObj(
      */
 
   restore:
+    /*
+     * 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);
+    }
     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);
@@ -4143,7 +4268,17 @@ Tcl_GetsObj(
      */
 
   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);
+    }
     UpdateInterest(chanPtr);
+    Tcl_Release(chanPtr);
     return copiedTotal;
 }
 
@@ -4189,6 +4324,7 @@ TclGetsObjBinary(
      */
 
     chanPtr = statePtr->topChanPtr;
+    Tcl_Preserve(chanPtr);
 
     bufPtr = statePtr->inQueueHead;
 
@@ -4232,16 +4368,17 @@ TclGetsObjBinary(
 	     * device. Side effect is to allocate another channel buffer.
 	     */
 
-	    if (statePtr->flags & CHANNEL_BLOCKED) {
-		if (statePtr->flags & 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);
@@ -4284,7 +4421,7 @@ TclGetsObjBinary(
 	    SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF);
 	    statePtr->inputEncodingFlags |= TCL_ENCODING_END;
 	}
-	if (statePtr->flags & CHANNEL_EOF) {
+	if (GotFlag(statePtr, CHANNEL_EOF)) {
 	    skip = 0;
 	    eol = dstEnd;
 	    if ((dst == dstEnd) && (byteLen == oldLength)) {
@@ -4296,6 +4433,7 @@ TclGetsObjBinary(
 		byteArray = Tcl_SetByteArrayLength(objPtr, oldLength);
 		CommonGetsCleanup(chanPtr);
 		copiedTotal = -1;
+		ResetFlag(statePtr, CHANNEL_BLOCKED);
 		goto done;
 	    }
 	    goto gotEOL;
@@ -4354,12 +4492,12 @@ 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);
@@ -4388,6 +4526,7 @@ TclGetsObjBinary(
 
   done:
     UpdateInterest(chanPtr);
+    Tcl_Release(chanPtr);
     return copiedTotal;
 }
 
@@ -4464,7 +4603,7 @@ 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
@@ -4498,14 +4637,6 @@ FilterInputBytes(
 	 */
 
     read:
-	if (statePtr->flags & CHANNEL_BLOCKED) {
-	    if (statePtr->flags & CHANNEL_NONBLOCKING) {
-		gsPtr->charsWrote = 0;
-		gsPtr->rawRead = 0;
-		return -1;
-	    }
-	    ResetFlag(statePtr, CHANNEL_BLOCKED);
-	}
 	if (GetInput(chanPtr) != 0) {
 	    gsPtr->charsWrote = 0;
 	    gsPtr->rawRead = 0;
@@ -4513,6 +4644,11 @@ FilterInputBytes(
 	}
 	bufPtr = statePtr->inQueueTail;
 	gsPtr->bufPtr = bufPtr;
+	if (bufPtr == NULL) {
+	    gsPtr->charsWrote = 0;
+	    gsPtr->rawRead = 0;
+	    return -1;
+	}
     }
 
     /*
@@ -4521,8 +4657,7 @@ FilterInputBytes(
      * string rep if we need more space.
      */
 
-    rawStart = RemovePoint(bufPtr);
-    raw = rawStart;
+    raw = RemovePoint(bufPtr);
     rawLen = BytesLeft(bufPtr);
 
     dst = *gsPtr->dstPtr;
@@ -4579,7 +4714,7 @@ FilterInputBytes(
 		 * returning those UTF-8 characters because a EOL might be
 		 * present in them.
 		 */
-	    } else if (statePtr->flags & CHANNEL_EOF) {
+	    } else if (GotFlag(statePtr, CHANNEL_EOF)) {
 		/*
 		 * There was a partial character followed by EOF on the
 		 * device. Fall through, returning that nothing was found.
@@ -4589,9 +4724,15 @@ 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 {
@@ -4601,7 +4742,7 @@ FilterInputBytes(
 		statePtr->inQueueTail = nextPtr;
 	    }
 	    extra = rawLen - gsPtr->rawRead;
-	    memcpy(nextPtr->buf + BUFFER_PADDING - extra,
+	    memcpy(nextPtr->buf + (BUFFER_PADDING - extra),
 		    raw + gsPtr->rawRead, (size_t) extra);
 	    nextPtr->nextRemoved -= extra;
 	    bufPtr->nextAdded -= extra;
@@ -4668,7 +4809,7 @@ PeekAhead(
 
 		goto cleanup;
 	    }
-	    if ((statePtr->flags & CHANNEL_NONBLOCKING) == 0) {
+	    if (!GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
 		blockModeProc = Tcl_ChannelBlockModeProc(chanPtr->typePtr);
 		if (blockModeProc == NULL) {
 		    /*
@@ -4836,7 +4977,7 @@ Tcl_ReadRaw(
     Channel *chanPtr = (Channel *) chan;
     ChannelState *statePtr = chanPtr->state;
 				/* State info for channel */
-    int nread, result, copied, copiedNow;
+    int nread, copied, copiedNow = INT_MAX;
 
     /*
      * The check below does too much because it will reject a call to this
@@ -4860,108 +5001,33 @@ Tcl_ReadRaw(
      * requests more bytes.
      */
 
-    for (copied = 0; copied < bytesToRead; copied += copiedNow) {
-	copiedNow = CopyBuffer(chanPtr, bufPtr + copied,
-		bytesToRead - copied);
-	if (copiedNow == 0) {
-	    if (statePtr->flags & CHANNEL_EOF) {
-		goto done;
-	    }
-	    if (statePtr->flags & CHANNEL_BLOCKED) {
-		if (statePtr->flags & CHANNEL_NONBLOCKING) {
-		    goto done;
-		}
-		ResetFlag(statePtr, CHANNEL_BLOCKED);
-	    }
-
-#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 ((statePtr->flags & CHANNEL_NONBLOCKING) &&
-		    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
-		    !(statePtr->flags & CHANNEL_HAS_MORE_DATA)) {
-		/*
-		 * We bypass the driver; it would block as no data is
-		 * available.
-		 */
-
-		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.
-		 */
-
-		nread = ChanRead(chanPtr, bufPtr + copied,
-			bytesToRead - copied, &result);
-
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-	    }
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-
-	    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.
-		 */
-
-		if (nread < (bytesToRead - copied)) {
-		    SetFlag(statePtr, CHANNEL_BLOCKED);
-		}
-
-#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;
-		    }
+    Tcl_Preserve(chanPtr);
+    for (copied = 0; bytesToRead > 0 && copiedNow > 0;
+	    bufPtr+=copiedNow, bytesToRead-=copiedNow, copied+=copiedNow) {
+	copiedNow = CopyBuffer(chanPtr, bufPtr, bytesToRead);
+    }
 
-		    SetFlag(statePtr, CHANNEL_BLOCKED);
-		    result = EAGAIN;
-		}
+    if (bytesToRead > 0) {
+	/*
+	 * Now go to the driver to get as much as is possible to
+	 * fill the remaining request.  Since we're directly filling
+	 * the caller's buffer, retain the blocked flag.
+	 */
 
-		Tcl_SetErrno(result);
-		return -1;
+	nread = ChanRead(chanPtr, bufPtr, bytesToRead);
+	if (nread < 0) {
+	    if (!GotFlag(statePtr, CHANNEL_BLOCKED) || copied == 0) {
+		copied = -1;
 	    }
-
-	    return copied + nread;
+	} else {
+	    copied += nread;
+	}
+	if (copied != 0) {
+	    ResetFlag(statePtr, CHANNEL_EOF);
 	}
     }
 
-  done:
+    Tcl_Release(chanPtr);
     return copied;
 }
 
@@ -5058,8 +5124,9 @@ 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
 
     /*
@@ -5069,9 +5136,14 @@ 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);
@@ -5080,27 +5152,23 @@ 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);
 	    }
 
 	    /*
@@ -5121,22 +5189,24 @@ DoReadChars(
 	}
 
 	if (copiedNow < 0) {
-	    if (statePtr->flags & CHANNEL_EOF) {
+	    if (GotFlag(statePtr, CHANNEL_EOF)) {
 		break;
 	    }
-	    if (statePtr->flags & CHANNEL_BLOCKED) {
-		if (statePtr->flags & 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;
@@ -5144,20 +5214,31 @@ DoReadChars(
 	}
     }
 
-    ResetFlag(statePtr, CHANNEL_BLOCKED);
-    if (encoding == NULL) {
-	Tcl_SetByteArrayLength(objPtr, offset);
-    } else {
-	Tcl_SetObjLength(objPtr, offset);
+    /*
+     * 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);
+    }
+
+    /*
+     * 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);
     }
 
     /*
      * Update the notifier state so we don't block while there is still data
      * in the buffers.
      */
-
-  done:
     UpdateInterest(chanPtr);
+    Tcl_Release(chanPtr);
     return copied;
 }
 
@@ -5175,13 +5256,11 @@ 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.
  *
  *---------------------------------------------------------------------------
  */
@@ -5194,72 +5273,22 @@ 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;
+    ChannelBuffer *bufPtr = statePtr->inQueueHead;
+    int srcLen = BytesLeft(bufPtr);
+    int toRead = bytesToRead>srcLen || bytesToRead<0 ? srcLen : bytesToRead;
 
-    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.
-	 */
-
-	length = offset * 2;
-	if (offset < toRead) {
-	    length = offset + toRead + 1;
-	}
-	dst = (char *) Tcl_SetByteArrayLength(objPtr, length);
-    }
-    dst += offset;
-
-    if (statePtr->flags & 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;
 }
 
 /*
@@ -5303,263 +5332,344 @@ 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;
-
-    factor = *factorPtr;
-    offset = *offsetPtr;
+    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);
 
-    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 = ((unsigned) 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.
-     *
-     * 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.
+     * 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.
      *
-     * 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 (statePtr->flags & 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 (GotFlag(statePtr, 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.
+	     */
 
-	if (dstWrote == 0) {
-	    return -1;
+	    dstLimit = Tcl_UtfAtIndex(dst, charsToRead + 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;
+	    if (dst[0] == '\n') {
+		assert(statePtr->inputTranslation == TCL_TRANSLATE_AUTO);
+		assert(dstRead == 1);
 
-	eof = Tcl_UtfAtIndex(dst, toRead);
-	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);
+	}
 
-    bufPtr->nextRemoved += srcRead;
-    if (dstWrote > srcRead + 1) {
-	*factorPtr = dstWrote * UTF_EXPANSION_FACTOR / srcRead;
+	statePtr->inputEncodingFlags &= ~TCL_ENCODING_START;
+
+    consume:
+	bufPtr->nextRemoved += srcRead;
+	if (dstWrote > srcRead + 1) {
+	    *factorPtr = dstWrote * UTF_EXPANSION_FACTOR / srcRead;
+	}
+	Tcl_SetObjLength(objPtr, numBytes + dstWrote);
+	return numChars;
     }
-    *offsetPtr += dstWrote;
-    return numChars;
 }
 
 /*
@@ -5580,7 +5690,7 @@ ReadChars(
  *---------------------------------------------------------------------------
  */
 
-static int
+static void 
 TranslateInputEOL(
     ChannelState *statePtr,	/* Channel being read, for EOL translation and
 				 * EOF character. */
@@ -5589,133 +5699,138 @@ 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;
-
-	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;
-
-	dst = dstStart;
-	src = srcStart;
-	srcEnd = srcStart + dstLen;
-	srcMax = srcStart + *srcLenPtr;
+	const char *crFound, *src = srcStart;
+	char *dst = dstStart;
+	int lesser;
 
-	if ((statePtr->flags & INPUT_SAW_CR) && (src < srcMax)) {
-	    if (*src == '\n') {
-		src++;
-	    }
+	if (GotFlag(statePtr, 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
@@ -5724,12 +5839,8 @@ 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;
 }
 
 /*
@@ -5783,16 +5894,11 @@ 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 (statePtr->flags & 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);
@@ -5857,14 +5963,6 @@ 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;
@@ -5915,7 +6013,7 @@ DiscardInputQueued(
      */
 
     if (discardSavedBuffers && statePtr->saveInBufPtr != NULL) {
-	ckfree((char *) statePtr->saveInBufPtr);
+	ReleaseChannelBuffer(statePtr->saveInBufPtr);
 	statePtr->saveInBufPtr = NULL;
     }
 }
@@ -5927,6 +6025,9 @@ 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.
@@ -5959,21 +6060,28 @@ 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;
@@ -5994,21 +6102,20 @@ 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((char *) bufPtr);
+		&& (bufPtr->bufLength - BUFFER_PADDING != statePtr->bufSize)) {
+	    ReleaseChannelBuffer(bufPtr);
 	    bufPtr = NULL;
 	}
 
@@ -6017,21 +6124,8 @@ 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;
@@ -6039,80 +6133,22 @@ 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 (statePtr->flags & CHANNEL_EOF) {
-	return 0;
-    }
-
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-    /*
-     * [SF Tcl 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.
-     */
+    PreserveChannelBuffer(bufPtr);
+    nread = ChanRead(chanPtr, InsertPoint(bufPtr), toRead);
 
-    if ((statePtr->flags & CHANNEL_NONBLOCKING) &&
-	    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
-	    !(statePtr->flags & CHANNEL_HAS_MORE_DATA)) {
-	/*
-	 * Bypass the driver, it would block, as no data is available
-	 */
-
-	nread = -1;
-	result = EWOULDBLOCK;
+    if (nread < 0) {
+	result = Tcl_GetErrno();
     } else {
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-
-	nread = ChanRead(chanPtr, InsertPoint(bufPtr), toRead, &result);
-
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
-    }
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-
-    if (nread > 0) {
+	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) {
-	    /*
-	     * [SF Tcl 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;
 }
 
 /*
@@ -6227,28 +6263,19 @@ Tcl_Seek(
      */
 
     wasAsync = 0;
-    if (statePtr->flags & CHANNEL_NONBLOCKING) {
+    if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
 	wasAsync = 1;
 	result = StackSetBlockMode(chanPtr, TCL_MODE_BLOCKING);
 	if (result != 0) {
 	    return Tcl_LongAsWide(-1);
 	}
 	ResetFlag(statePtr, CHANNEL_NONBLOCKING);
-	if (statePtr->flags & BG_FLUSH_SCHEDULED) {
+	if (GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	    ResetFlag(statePtr, BG_FLUSH_SCHEDULED);
 	}
     }
 
     /*
-     * 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
@@ -6570,8 +6597,7 @@ CheckChannelErrors(
      * order to drain data from stacked channels.
      */
 
-    if ((statePtr->flags & CHANNEL_CLOSED) &&
-	    ((flags & CHANNEL_RAW_MODE) == 0)) {
+    if (GotFlag(statePtr, CHANNEL_CLOSED) && !(flags & CHANNEL_RAW_MODE)) {
 	Tcl_SetErrno(EACCES);
 	return -1;
     }
@@ -6580,7 +6606,7 @@ CheckChannelErrors(
      * Fail if the channel is not opened for desired operation.
      */
 
-    if ((statePtr->flags & direction) == 0) {
+    if (GotFlag(statePtr, direction) == 0) {
 	Tcl_SetErrno(EACCES);
 	return -1;
     }
@@ -6593,23 +6619,13 @@ CheckChannelErrors(
      * retrieving and transforming the data to copy.
      */
 
-    if (BUSY_STATE(statePtr,flags) && ((flags & CHANNEL_RAW_MODE) == 0)) {
+    if (BUSY_STATE(statePtr, flags) && ((flags & CHANNEL_RAW_MODE) == 0)) {
 	Tcl_SetErrno(EBUSY);
 	return -1;
     }
 
     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 ((statePtr->flags & CHANNEL_STICKY_EOF) == 0) {
-	    ResetFlag(statePtr, CHANNEL_EOF);
-	}
-	ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_NEED_MORE_DATA);
+	ResetFlag(statePtr, CHANNEL_NEED_MORE_DATA);
     }
 
     return 0;
@@ -6638,8 +6654,8 @@ Tcl_Eof(
     ChannelState *statePtr = ((Channel *) chan)->state;
 				/* State of real channel structure. */
 
-    return ((statePtr->flags & CHANNEL_STICKY_EOF) ||
-	    ((statePtr->flags & CHANNEL_EOF) &&
+    return (GotFlag(statePtr, CHANNEL_STICKY_EOF) ||
+	    (GotFlag(statePtr, CHANNEL_EOF) &&
 	    (Tcl_InputBuffered(chan) == 0))) ? 1 : 0;
 }
 
@@ -6666,7 +6682,7 @@ Tcl_InputBlocked(
     ChannelState *statePtr = ((Channel *) chan)->state;
 				/* State of real channel structure. */
 
-    return (statePtr->flags & CHANNEL_BLOCKED) ? 1 : 0;
+    return GotFlag(statePtr, CHANNEL_BLOCKED) ? 1 : 0;
 }
 
 /*
@@ -6825,7 +6841,27 @@ 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;
+    }
 }
 
 /*
@@ -7259,6 +7295,7 @@ Tcl_SetChannelOption(
 	    return TCL_ERROR;
 	}
 	Tcl_SetChannelBufferSize(chan, newBufferSize);
+	return TCL_OK;
     } else if (HaveOpt(2, "-encoding")) {
 	Tcl_Encoding encoding;
 
@@ -7276,7 +7313,8 @@ 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);
@@ -7289,6 +7327,7 @@ 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;
@@ -7308,10 +7347,10 @@ Tcl_SetChannelOption(
 		ckfree((char *) argv);
 		return TCL_ERROR;
 	    }
-	    if (statePtr->flags & TCL_READABLE) {
+	    if (GotFlag(statePtr, TCL_READABLE)) {
 		statePtr->inEofChar = inValue;
 	    }
-	    if (statePtr->flags & TCL_WRITABLE) {
+	    if (GotFlag(statePtr, TCL_WRITABLE)) {
 		statePtr->outEofChar = outValue;
 	    }
 	} else {
@@ -7345,11 +7384,11 @@ Tcl_SetChannelOption(
 	}
 
 	if (argc == 1) {
-	    readMode = (statePtr->flags & TCL_READABLE) ? argv[0] : NULL;
-	    writeMode = (statePtr->flags & TCL_WRITABLE) ? argv[0] : NULL;
+	    readMode = GotFlag(statePtr, TCL_READABLE) ? argv[0] : NULL;
+	    writeMode = GotFlag(statePtr, TCL_WRITABLE) ? argv[0] : NULL;
 	} else if (argc == 2) {
-	    readMode = (statePtr->flags & TCL_READABLE) ? argv[0] : NULL;
-	    writeMode = (statePtr->flags & TCL_WRITABLE) ? argv[1] : NULL;
+	    readMode = GotFlag(statePtr, TCL_READABLE) ? argv[0] : NULL;
+	    writeMode = GotFlag(statePtr, TCL_WRITABLE) ? argv[1] : NULL;
 	} else {
 	    if (interp) {
 		Tcl_AppendResult(interp,
@@ -7450,22 +7489,6 @@ 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;
 }
 
@@ -7557,21 +7580,6 @@ 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) &&
-	    (statePtr->flags & CHANNEL_NONBLOCKING) &&
-	    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
-	    !(statePtr->flags & 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.
@@ -7630,7 +7638,7 @@ Tcl_NotifyChannel(
      * don't call any write handlers before the flush is complete.
      */
 
-    if ((statePtr->flags & BG_FLUSH_SCHEDULED) && (mask & TCL_WRITABLE)) {
+    if (GotFlag(statePtr, BG_FLUSH_SCHEDULED) && (mask & TCL_WRITABLE)) {
 	FlushChannel(NULL, chanPtr, 1);
 	mask &= ~TCL_WRITABLE;
     }
@@ -7700,12 +7708,17 @@ 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.
      */
 
-    if (statePtr->flags & BG_FLUSH_SCHEDULED) {
+    if (GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	mask |= TCL_WRITABLE;
     }
 
@@ -7717,7 +7730,7 @@ UpdateInterest(
      */
 
     if (mask & TCL_READABLE) {
-	if (!(statePtr->flags & CHANNEL_NEED_MORE_DATA)
+	if (!GotFlag(statePtr, CHANNEL_NEED_MORE_DATA)
 		&& (statePtr->inQueueHead != NULL)
 		&& IsBufferReady(statePtr->inQueueHead)) {
 	    mask &= ~TCL_READABLE;
@@ -7796,7 +7809,7 @@ ChannelTimerProc(
     ChannelState *statePtr = chanPtr->state;
 				/* State info for channel */
 
-    if (!(statePtr->flags & CHANNEL_NEED_MORE_DATA)
+    if (!GotFlag(statePtr, CHANNEL_NEED_MORE_DATA)
 	    && (statePtr->interestMask & TCL_READABLE)
 	    && (statePtr->inQueueHead != NULL)
 	    && IsBufferReady(statePtr->inQueueHead)) {
@@ -7806,29 +7819,8 @@ ChannelTimerProc(
 	 */
 
 	statePtr->timer = Tcl_CreateTimerHandler(0, 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 ((statePtr->flags & 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_NotifyChannel((Tcl_Channel) chanPtr, TCL_READABLE);
 	Tcl_Release(statePtr);
     } else {
 	statePtr->timer = NULL;
@@ -8241,7 +8233,7 @@ Tcl_FileEventObjCmd(
     }
     chanPtr = (Channel *) chan;
     statePtr = chanPtr->state;
-    if ((statePtr->flags & mask) == 0) {
+    if (GotFlag(statePtr, mask) == 0) {
 	Tcl_AppendResult(interp, "channel is not ",
 		(mask == TCL_READABLE) ? "readable" : "writable", NULL);
 	return TCL_ERROR;
@@ -8751,13 +8743,24 @@ CopyData(
  *
  * DoRead --
  *
- *	Reads a given number of bytes from a channel.
+ *	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.
@@ -8768,288 +8771,151 @@ 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. */
 {
     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. */
+    char *p = dst;
 
-    /*
-     * 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.
-     */
+    Tcl_Preserve(chanPtr);
+    while (bytesToRead) {
+	/*
+	 * Each pass through the loop is intended to process up to 
+	 * one channel buffer.
+	 */
 
-    if (!(statePtr->flags & CHANNEL_STICKY_EOF)) {
-	ResetFlag(statePtr, CHANNEL_EOF);
-    }
-    ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_NEED_MORE_DATA);
+	int bytesRead, bytesWritten;
+	ChannelBuffer *bufPtr = statePtr->inQueueHead;
 
-    for (copied = 0; copied < toRead; copied += copiedNow) {
-	copiedNow = CopyAndTranslateBuffer(statePtr, bufPtr + copied,
-		toRead - copied);
-	if (copiedNow == 0) {
-	    if (statePtr->flags & CHANNEL_EOF) {
-		goto done;
-	    }
-	    if (statePtr->flags & CHANNEL_BLOCKED) {
-		if (statePtr->flags & CHANNEL_NONBLOCKING) {
-		    goto done;
-		}
-		ResetFlag(statePtr, CHANNEL_BLOCKED);
-	    }
-	    result = GetInput(chanPtr);
-	    if (result != 0) {
-		if (result != EAGAIN) {
-		    copied = -1;
-		}
-		goto done;
-	    }
-	}
-    }
+	/*
+	 * When there's no buffered data to read, and we're at EOF,
+	 * escape to the caller.
+	 */
 
-    ResetFlag(statePtr, CHANNEL_BLOCKED);
+	if (GotFlag(statePtr, CHANNEL_EOF)
+		&& (bufPtr == NULL || IsBufferEmpty(bufPtr))) {
+	    break;
+	}
 
-    /*
-     * Update the notifier state so we don't block while there is still data
-     * in the buffers.
-     */
+	/* If there is no full buffer, attempt to create and/or fill one. */
 
-  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.
- *
- *----------------------------------------------------------------------
- */
+	while (!IsBufferFull(bufPtr)) {
+	    int code;
 
-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. */
+	moreData:
+	    code = GetInput(chanPtr);
+	    bufPtr = statePtr->inQueueHead;
 
-    /*
-     * 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.
-     */
+	    assert (bufPtr != NULL);
 
-    if (statePtr->inQueueHead == NULL) {
-	return 0;
-    }
-    bufPtr = statePtr->inQueueHead;
-    bytesInBuffer = BytesLeft(bufPtr);
+	    if (GotFlag(statePtr, CHANNEL_EOF|CHANNEL_BLOCKED)) {
+		/* Further reads cannot do any more */
+		break;
+	    }
+	    
+	    if (code) {
+		/* Read error */
+		UpdateInterest(chanPtr);
+		Tcl_Release(chanPtr);
+		return -1;
+	    }
 
-    copied = 0;
-    switch (statePtr->inputTranslation) {
-    case TCL_TRANSLATE_LF:
-	if (bytesInBuffer == 0) {
-	    return 0;
+	    assert (IsBufferFull(bufPtr));
 	}
 
-	/*
-	 * Copy the current chunk into the result buffer.
-	 */
+	assert (bufPtr != NULL);
 
-	if (bytesInBuffer < space) {
-	    space = bytesInBuffer;
-	}
-	memcpy(result, RemovePoint(bufPtr), (size_t) space);
-	bufPtr->nextRemoved += space;
-	copied = space;
-	break;
-    case TCL_TRANSLATE_CR: {
-	char *end;
+	bytesRead = BytesLeft(bufPtr);
+	bytesWritten = bytesToRead;
 
-	if (bytesInBuffer == 0) {
-	    return 0;
-	}
+	TranslateInputEOL(statePtr, p, RemovePoint(bufPtr),
+		&bytesWritten, &bytesRead);
+	bufPtr->nextRemoved += bytesRead;
+	p += bytesWritten;
+	bytesToRead -= bytesWritten;
 
-	/*
-	 * Copy the current chunk into the result buffer, then replace all \r
-	 * with \n.
-	 */
-
-	if (bytesInBuffer < space) {
-	    space = bytesInBuffer;
-	}
-	memcpy(result, RemovePoint(bufPtr), (size_t) space);
-	bufPtr->nextRemoved += space;
-	copied = space;
+	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.
+	     */
 
-	for (end = result + copied; result < end; result++) {
-	    if (*result == '\r') {
-		*result = '\n';
+	    if (bytesToRead == 0) {
+		UpdateInterest(chanPtr);
+		break;
 	    }
-	}
-	break;
-    }
-    case TCL_TRANSLATE_CRLF: {
-	char *src, *end, *dst;
-	int curByte;
 
-	/*
-	 * If there is a held-back "\r" at EOF, produce it now.
-	 */
+	    /*
+	     * 1) We're @EOF because we saw eof char.
+	     */
 
-	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;
+	    if (statePtr->inEofChar
+		    && RemovePoint(bufPtr)[0] == statePtr->inEofChar) {
+		UpdateInterest(chanPtr);
+		break;
 	    }
-	    return 0;
-	}
 
-	/*
-	 * Copy the current chunk and replace "\r\n" with "\n" (but not
-	 * standalone "\r"!).
-	 */
-
-	if (bytesInBuffer < space) {
-	    space = bytesInBuffer;
-	}
-	memcpy(result, RemovePoint(bufPtr), (size_t) space);
-	bufPtr->nextRemoved += space;
-	copied = space;
-
-	end = result + copied;
-	dst = result;
-	for (src = result; src < end; src++) {
-	    curByte = *src;
-	    if (curByte == '\n') {
-		ResetFlag(statePtr, INPUT_SAW_CR);
-	    } else if (statePtr->flags & INPUT_SAW_CR) {
-		ResetFlag(statePtr, INPUT_SAW_CR);
-		*dst = '\r';
-		dst++;
-	    }
-	    if (curByte == '\r') {
-		SetFlag(statePtr, INPUT_SAW_CR);
-	    } else {
-		*dst = (char) curByte;
-		dst++;
-	    }
-	}
-	copied = dst - result;
-	break;
-    }
-    case TCL_TRANSLATE_AUTO: {
-	char *src, *end, *dst;
-	int curByte;
+	    /*
+	     * 2) The buffer holds a \r while in CRLF translation,
+	     *    followed by the end of the buffer.
+	     */
 
-	if (bytesInBuffer == 0) {
-	    return 0;
-	}
+	    assert(statePtr->inputTranslation == TCL_TRANSLATE_CRLF);
+	    assert(RemovePoint(bufPtr)[0] == '\r');
+	    assert(BytesLeft(bufPtr) == 1);
 
-	/*
-	 * Loop over the current buffer, converting "\r" and "\r\n" to "\n".
-	 */
+	    if (bufPtr->nextPtr == NULL) {
+		/* There's no more buffered data.... */
 
-	if (bytesInBuffer < space) {
-	    space = bytesInBuffer;
-	}
-	memcpy(result, RemovePoint(bufPtr), (size_t) space);
-	bufPtr->nextRemoved += space;
-	copied = space;
+		if (GotFlag(statePtr, CHANNEL_EOF)) {
+		    /* ...and there never will be. */
 
-	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') || !(statePtr->flags & INPUT_SAW_CR)) {
-		    *dst = (char) curByte;
-		    dst++;
+		    *p++ = '\r';
+		    bytesToRead--;
+		    bufPtr->nextRemoved++;
+		} else if (GotFlag(statePtr, 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;
 		}
-		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.
-     */
+	    if (bufPtr->nextPtr) {
+		/* There's a next buffer.  Shift orphan \r to it. */
 
-    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.
-		 */
+		ChannelBuffer *nextPtr = bufPtr->nextPtr;
 
-		SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF);
-		statePtr->inputEncodingFlags |= TCL_ENCODING_END;
-		copied = i;
-		break;
+		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)) {
-	statePtr->inQueueHead = bufPtr->nextPtr;
-	if (statePtr->inQueueHead == NULL) {
-	    statePtr->inQueueTail = NULL;
+	if (GotFlag(statePtr, CHANNEL_NONBLOCKING|CHANNEL_BLOCKED)
+		== (CHANNEL_NONBLOCKING|CHANNEL_BLOCKED)) {
+	    break;
 	}
-	RecycleBuffer(statePtr, bufPtr, 0);
+    }
+    if (bytesToRead == 0) {
+	ResetFlag(statePtr, CHANNEL_BLOCKED);
     }
 
-    /*
-     * 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;
+    Tcl_Release(chanPtr);
+    return (int)(p - dst);
 }
 
 /*
@@ -9259,12 +9125,15 @@ 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) {
@@ -10409,11 +10278,13 @@ 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.
 	 */
-	statePtr  = GET_CHANNELSTATE(objPtr);
-	if (statePtr->flags & (CHANNEL_TAINTED|CHANNEL_CLOSED)) {
+
+	statePtr = GET_CHANNELSTATE(objPtr);
+	if (GotFlag(statePtr, CHANNEL_TAINTED|CHANNEL_CLOSED)) {
 	    ResetFlag(statePtr, CHANNEL_TAINTED);
 	    Tcl_Release((ClientData) statePtr);
 	    objPtr->typePtr = NULL;
@@ -10483,20 +10354,14 @@ 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';
@@ -10511,5 +10376,7 @@ DumpFlags(
  * mode: c
  * c-basic-offset: 4
  * fill-column: 78
+ * tab-width: 8
+ * indent-tabs-mode: nil
  * End:
  */
diff --git a/generic/tclIO.h b/generic/tclIO.h
index ebf2ef7..59182ec 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 2958bc8..afd6272 100644
--- a/generic/tclIOCmd.c
+++ b/generic/tclIOCmd.c
@@ -177,6 +177,7 @@ Tcl_PutsObjCmd(
 	return TCL_ERROR;
     }
 
+    Tcl_Preserve(chan);
     result = Tcl_WriteObj(chan, string);
     if (result < 0) {
 	goto error;
@@ -187,6 +188,7 @@ Tcl_PutsObjCmd(
 	    goto error;
 	}
     }
+    Tcl_Release(chan);
     return TCL_OK;
 
     /*
@@ -202,6 +204,7 @@ Tcl_PutsObjCmd(
 		TclGetString(chanObjPtr), "\": ",
 		Tcl_PosixError(interp), NULL);
     }
+    Tcl_Release(chan);
     return TCL_ERROR;
 }
 
@@ -248,6 +251,7 @@ Tcl_FlushObjCmd(
 	return TCL_ERROR;
     }
 
+    Tcl_Preserve(chan);
     if (Tcl_Flush(chan) != TCL_OK) {
 	/*
 	 * TIP #219.
@@ -261,8 +265,10 @@ Tcl_FlushObjCmd(
 		    TclGetString(chanObjPtr), "\": ",
 		    Tcl_PosixError(interp), NULL);
 	}
+	Tcl_Release(chan);
 	return TCL_ERROR;
     }
+    Tcl_Release(chan);
     return TCL_OK;
 }
 
@@ -295,6 +301,7 @@ 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?");
@@ -310,6 +317,7 @@ Tcl_GetsObjCmd(
 	return TCL_ERROR;
     }
 
+    Tcl_Preserve(chan);
     linePtr = Tcl_NewObj();
     lineLen = Tcl_GetsObj(chan, linePtr);
     if (lineLen < 0) {
@@ -329,21 +337,24 @@ Tcl_GetsObjCmd(
 			TclGetString(chanObjPtr), "\": ",
 			Tcl_PosixError(interp), NULL);
 	    }
-	    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));
-	return TCL_OK;
     } else {
 	Tcl_SetObjResult(interp, linePtr);
     }
-    return TCL_OK;
+  done:
+    Tcl_Release(chan);
+    return code;
 }
 
 /*
@@ -447,6 +458,7 @@ Tcl_ReadObjCmd(
 
     resultPtr = Tcl_NewObj();
     Tcl_IncrRefCount(resultPtr);
+    Tcl_Preserve(chan);
     charactersRead = Tcl_ReadChars(chan, resultPtr, toRead, 0);
     if (charactersRead < 0) {
 	/*
@@ -462,6 +474,7 @@ Tcl_ReadObjCmd(
 		    TclGetString(chanObjPtr), "\": ",
 		    Tcl_PosixError(interp), NULL);
 	}
+	Tcl_Release(chan);
 	Tcl_DecrRefCount(resultPtr);
 	return TCL_ERROR;
     }
@@ -480,6 +493,7 @@ Tcl_ReadObjCmd(
 	}
     }
     Tcl_SetObjResult(interp, resultPtr);
+    Tcl_Release(chan);
     Tcl_DecrRefCount(resultPtr);
     return TCL_OK;
 }
@@ -539,6 +553,7 @@ Tcl_SeekObjCmd(
 	mode = modeArray[optionIndex];
     }
 
+    Tcl_Preserve(chan);
     result = Tcl_Seek(chan, offset, mode);
     if (result == Tcl_LongAsWide(-1)) {
 	/*
@@ -552,8 +567,10 @@ Tcl_SeekObjCmd(
 		    TclGetString(objv[1]), "\": ",
 		    Tcl_PosixError(interp), NULL);
 	}
+	Tcl_Release(chan);
 	return TCL_ERROR;
     }
+    Tcl_Release(chan);
     return TCL_OK;
 }
 
@@ -584,6 +601,7 @@ Tcl_TellObjCmd(
 {
     Tcl_Channel chan;		/* The channel to tell on. */
     Tcl_WideInt newLoc;
+    int code;
 
     if (objc != 2) {
 	Tcl_WrongNumArgs(interp, 1, objv, "channelId");
@@ -599,6 +617,7 @@ Tcl_TellObjCmd(
 	return TCL_ERROR;
     }
 
+    Tcl_Preserve(chan);
     newLoc = Tcl_Tell(chan);
 
     /*
@@ -607,7 +626,10 @@ Tcl_TellObjCmd(
      * them into the regular interpreter result.
      */
 
-    if (TclChanCaughtErrorBypass(interp, chan)) {
+
+    code  = TclChanCaughtErrorBypass(interp, chan);
+    Tcl_Release(chan);
+    if (code) {
 	return TCL_ERROR;
     }
 
diff --git a/generic/tclIOGT.c b/generic/tclIOGT.c
index eed21fb..fe0a880 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((char *) 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 = (TransformChannelData *) 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_AppendResult(interp, "\nfailed to stack channel \"",
 		Tcl_GetChannelName(chan), "\"", NULL);
-	Tcl_DecrRefCount(dataPtr->command);
-	ResultClear(&dataPtr->result);
-	ckfree((char *) 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((char *) 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;
 	}
 
 	/*
@@ -656,43 +683,41 @@ 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.
-	     */
 
-	    if ((Tcl_GetErrno() == EAGAIN) && (gotBytes > 0)) {
-		return gotBytes;
+	    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.
+		 */
+
+		break;
 	    }
 
+	    /*
+	     * 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.
+	     */
+
 	    *errorCodePtr = Tcl_GetErrno();
-	    return -1;
+	    gotBytes = -1;
+	    break;
 	} 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.
+	     * Zero returned from Tcl_ReadRaw() always indicates EOF
+	     * on the down channel.
 	     */
 
-	    if (!Tcl_Eof(downChan)) {
-		if ((gotBytes == 0) && (dataPtr->flags & CHANNEL_ASYNC)) {
-		    *errorCodePtr = EWOULDBLOCK;
-		    return -1;
-		}
-		return gotBytes;
-	    }
-
 	    if (dataPtr->readIsFlushed) {
 		/*
 		 * Already flushed, nothing to do anymore.
 		 */
 
-		return gotBytes;
+		break;
 	    }
 
 	    dataPtr->readIsFlushed = 1;
@@ -704,7 +729,7 @@ TransformInputProc(
 		 * We had nothing to flush.
 		 */
 
-		return gotBytes;
+		break;
 	    }
 
 	    continue;		/* at: while (toRead > 0) */
@@ -718,9 +743,11 @@ 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;
 }
@@ -762,11 +789,13 @@ 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;
 }
@@ -819,6 +848,7 @@ TransformSeekProc(
      * request down, unchanged.
      */
 
+    PreserveData(dataPtr);
     if (dataPtr->mode & TCL_WRITABLE) {
 	ExecuteCallback(dataPtr, NULL, A_FLUSH_WRITE, NULL, 0, TRANSMIT_DOWN,
 		P_NO_PRESERVE);
@@ -830,6 +860,7 @@ TransformSeekProc(
 	ResultClear(&dataPtr->result);
 	dataPtr->readIsFlushed = 0;
     }
+    ReleaseData(dataPtr);
 
     return parentSeekProc(Tcl_GetChannelInstanceData(parent), offset, mode,
 	    errorCodePtr);
@@ -890,6 +921,7 @@ TransformWideSeekProc(
      * request down, unchanged.
      */
 
+    PreserveData(dataPtr);
     if (dataPtr->mode & TCL_WRITABLE) {
 	ExecuteCallback(dataPtr, NULL, A_FLUSH_WRITE, NULL, 0, TRANSMIT_DOWN,
 		P_NO_PRESERVE);
@@ -901,6 +933,7 @@ TransformWideSeekProc(
 	ResultClear(&dataPtr->result);
 	dataPtr->readIsFlushed = 0;
     }
+    ReleaseData(dataPtr);
 
     /*
      * If we have a wide seek capability, we should stick with that.
@@ -1055,6 +1088,9 @@ 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 ca3ab4b..3107f9e 100644
--- a/generic/tclIORChan.c
+++ b/generic/tclIORChan.c
@@ -91,31 +91,9 @@ typedef struct {
 #ifdef TCL_THREADS
     Tcl_ThreadId thread;	/* Thread the 'interp' belongs to. */
 #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
@@ -439,7 +417,7 @@ static ReflectedChannel * NewReflectedChannel(Tcl_Interp *interp,
 static Tcl_Obj *	NextHandle(void);
 static void		FreeReflectedChannel(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);
@@ -454,16 +432,14 @@ 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}";
 
 /*
@@ -568,10 +544,6 @@ 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.
@@ -585,7 +557,7 @@ 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) {
 	UnmarshallErrorResult(interp, resObj);
@@ -674,7 +646,11 @@ 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) {
 	/*
@@ -737,12 +713,10 @@ 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
@@ -1045,6 +1019,7 @@ ReflectClose(
     Tcl_Obj *resObj;		/* Result data for 'close' */
     ReflectedChannelMap* rcmPtr; /* Map of reflected channels with handlers in this interp */
     Tcl_HashEntry* hPtr;         /* Entry in the above map */
+    Tcl_ChannelType *tctPtr;
 
     if (TclInThreadExit()) {
 	/*
@@ -1081,18 +1056,11 @@ ReflectClose(
 	}
 #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;
     }
@@ -1118,7 +1086,7 @@ ReflectClose(
 	}
     } 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);
 	}
@@ -1156,6 +1124,11 @@ 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
     }
@@ -1193,18 +1166,6 @@ 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?
      */
 
@@ -1242,7 +1203,7 @@ 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) {
@@ -1308,18 +1269,6 @@ 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?
      */
 
@@ -1353,11 +1302,12 @@ 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) {
@@ -1369,6 +1319,14 @@ 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;
@@ -1398,6 +1356,7 @@ ReflectOutput(
  stop:
     Tcl_DecrRefCount(bufObj);
     Tcl_DecrRefCount(resObj);		/* Remove reference held from invoke */
+    Tcl_Release(rcPtr->interp);
     Tcl_Release(rcPtr);
     return written;
  invalid:
@@ -1470,7 +1429,7 @@ 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;
     }
@@ -1541,8 +1500,6 @@ ReflectWatch(
     ReflectedChannel *rcPtr = (ReflectedChannel *) 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.
@@ -1585,7 +1542,7 @@ 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);
@@ -1644,7 +1601,7 @@ 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 {
@@ -1718,7 +1675,7 @@ 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);
     }
@@ -1763,7 +1720,7 @@ 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?
@@ -1802,14 +1759,14 @@ 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);
     }
@@ -2021,16 +1978,13 @@ NewReflectedChannel(
     Tcl_Obj *handleObj)
 {
     ReflectedChannel *rcPtr;
-    int i, listc;
-    Tcl_Obj **listv;
+    MethodName mn = METH_BLOCKING;
 
     rcPtr = (ReflectedChannel *) 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;
 #ifdef TCL_THREADS
     rcPtr->thread = Tcl_GetCurrentThread();
@@ -2038,54 +1992,17 @@ 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 = (Tcl_Obj **) 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;
 }
 
@@ -2136,28 +2053,11 @@ FreeReflectedChannel(
     ReflectedChannel *rcPtr)
 {
     Channel *chanPtr = (Channel *) rcPtr->chan;
-    int i, n;
-
-    if (chanPtr->typePtr != &tclRChannelType) {
-	/*
-	 * Delete a cloned ChannelType structure.
-	 */
-
-	ckfree((char*) chanPtr->typePtr);
-    }
-
-    n = rcPtr->argc - 2;
-    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]);
 
-    ckfree((char*) rcPtr->argv);
+    Tcl_Release(chanPtr);
+    Tcl_DecrRefCount(rcPtr->name);
+    Tcl_DecrRefCount(rcPtr->methods);
+    Tcl_DecrRefCount(rcPtr->cmd);
     ckfree((char*) rcPtr);
 }
 
@@ -2188,16 +2088,16 @@ 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->interp) {
 	/*
@@ -2220,32 +2120,25 @@ 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
      * behind the channel id. If specified.
      */
 
-    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);
 	}
     }
 
@@ -2254,9 +2147,10 @@ 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_GlobalEvalObj(rcPtr->interp, cmd);
 
     /*
      * We do not try to extract the result information if the caller has no
@@ -2282,7 +2176,6 @@ InvokeTclMethod(
 	     */
 
 	    if (result != TCL_ERROR) {
-		Tcl_Obj *cmd = Tcl_NewListObj(cmdc, rcPtr->argv);
 		int cmdLen;
 		const char *cmdString = Tcl_GetStringFromObj(cmd, &cmdLen);
 
@@ -2296,25 +2189,17 @@ 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).
@@ -2827,17 +2712,19 @@ ForwardProc(
 	 * call upon for the driver.
 	 */
 
-    case ForwardedClose:
+    case ForwardedClose: {
 	/*
 	 * No parameters/results.
 	 */
 
-	if (InvokeTclMethod(rcPtr, "finalize", NULL, NULL, &resObj)!=TCL_OK) {
+	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
 	 *
@@ -2856,15 +2743,21 @@ ForwardProc(
 				  Tcl_GetChannelName (rcPtr->chan));
 	Tcl_DeleteHashEntry (hPtr);
 
+	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) {
@@ -2904,7 +2797,7 @@ 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) {
@@ -2945,7 +2838,7 @@ 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 {
@@ -2979,7 +2872,7 @@ 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;
@@ -2990,7 +2883,7 @@ 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);
 	}
@@ -3006,7 +2899,7 @@ 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);
 	}
@@ -3025,7 +2918,7 @@ 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 {
 	    Tcl_DStringAppend(paramPtr->getOpt.value,
@@ -3042,7 +2935,7 @@ 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/tclIOUtil.c b/generic/tclIOUtil.c
index 295e313..82ffd88 100644
--- a/generic/tclIOUtil.c
+++ b/generic/tclIOUtil.c
@@ -24,6 +24,12 @@
 #endif
 #include "tclFileSystem.h"
 
+#ifdef TCL_TEMPLOAD_NO_UNLINK
+#ifndef NO_FSTATFS
+#include <sys/statfs.h>
+#endif
+#endif
+
 /*
  * struct FilesystemRecord --
  *
@@ -3149,6 +3155,82 @@ Tcl_FSLoadFile(
 typedef int (Tcl_FSLoadFileProc2) (Tcl_Interp *interp, Tcl_Obj *pathPtr,
 	Tcl_LoadHandle *handlePtr, Tcl_FSUnloadFileProc **unloadProcPtr, int flags);
 
+/*
+ * 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
 TclLoadFile(
     Tcl_Interp *interp,		/* Used for error reporting. */
@@ -3353,7 +3435,9 @@ TclLoadFile(
      * 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 1348340..b30650d 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -2480,6 +2480,8 @@ MODULE_SCOPE char	tclEmptyString;
  *----------------------------------------------------------------
  */
 
+MODULE_SCOPE void	TclAppendBytesToByteArray(Tcl_Obj *objPtr,
+			    const unsigned char *bytes, int len);
 MODULE_SCOPE void       TclAdvanceContinuations(int* line, int** next, int loc);
 MODULE_SCOPE void       TclAdvanceLines(int *line, const char *start,
 			    const char *end);
@@ -2550,6 +2552,7 @@ 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(mp_int *a);
@@ -2570,6 +2573,8 @@ MODULE_SCOPE int	TclGetOpenModeEx(Tcl_Interp *interp,
 			    int *binaryPtr);
 MODULE_SCOPE Tcl_Obj *	TclGetProcessGlobalValue(ProcessGlobalValue *pgvPtr);
 MODULE_SCOPE const char *TclGetSrcInfoForCmd(Interp *iPtr, int *lenPtr);
+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);
@@ -3667,6 +3672,24 @@ MODULE_SCOPE void	TclDbInitNewObj(Tcl_Obj *objPtr, CONST char *file,
 
 /*
  *----------------------------------------------------------------
+ * Macro that encapsulates the logic that determines when it is safe to
+ * interpret a string as a byte array directly. In summary, the object must be
+ * a byte array and must not have a string representation (as the operations
+ * that it is used in are defined on strings, not byte arrays). Theoretically
+ * it is possible to also be efficient in the case where the object's bytes
+ * field is filled by generation from the byte array (c.f. list canonicality)
+ * but we don't do that at the moment since this is purely about efficiency.
+ * The ANSI C "prototype" for this macro is:
+ *
+ * MODULE_SCOPE int	TclIsPureByteArray(Tcl_Obj *objPtr);
+ *----------------------------------------------------------------
+ */
+
+#define TclIsPureByteArray(objPtr) \
+	(((objPtr)->typePtr==&tclByteArrayType) && ((objPtr)->bytes==NULL))
+
+/*
+ *----------------------------------------------------------------
  * Macro used by the Tcl core to compare Unicode strings. On big-endian
  * systems we can use the more efficient memcmp, but this would not be
  * lexically correct on little-endian systems. The ANSI C "prototype" for
diff --git a/generic/tclIntPlatDecls.h b/generic/tclIntPlatDecls.h
index 80dd2ad..fc20d09 100644
--- a/generic/tclIntPlatDecls.h
+++ b/generic/tclIntPlatDecls.h
@@ -847,9 +847,15 @@ extern TclIntPlatStubs *tclIntPlatStubsPtr;
 #undef TclpLocaltime_unix
 #undef TclpGmtime_unix
 
-#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/tclStringObj.c b/generic/tclStringObj.c
index a929d04..8c6a376 100644
--- a/generic/tclStringObj.c
+++ b/generic/tclStringObj.c
@@ -1139,7 +1139,8 @@ 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;
     }
 
     /*
@@ -1386,7 +1387,8 @@ AppendUnicodeToUnicodeRep(
 	 * due to the reallocs below.
 	 */
 	int offset = -1;
-	if (unicode >= stringPtr->unicode && unicode <= stringPtr->unicode 
+	if (unicode && unicode >= stringPtr->unicode
+		&& unicode <= stringPtr->unicode
 		+ stringPtr->uallocated / sizeof(Tcl_UniChar)) {
 	    offset = unicode - stringPtr->unicode;
 	}
@@ -1405,8 +1407,10 @@ AppendUnicodeToUnicodeRep(
      * trailing null.
      */
 
-    memcpy(stringPtr->unicode + stringPtr->numChars, unicode,
-	    appendNumChars * sizeof(Tcl_UniChar));
+    if (unicode) {
+	memcpy(stringPtr->unicode + stringPtr->numChars, unicode,
+		appendNumChars * sizeof(Tcl_UniChar));
+    }
     stringPtr->unicode[numChars] = 0;
     stringPtr->numChars = numChars;
     stringPtr->allocated = 0;
@@ -1478,8 +1482,8 @@ AppendUtfToUnicodeRep(
     int numBytes)		/* Number of bytes of "bytes" to convert. */
 {
     Tcl_DString dsPtr;
-    int numChars;
-    Tcl_UniChar *unicode;
+    int numChars = numBytes;
+    Tcl_UniChar *unicode = NULL;
 
     if (numBytes < 0) {
 	numBytes = (bytes ? strlen(bytes) : 0);
@@ -1489,8 +1493,11 @@ AppendUtfToUnicodeRep(
     }
 
     Tcl_DStringInit(&dsPtr);
-    numChars = Tcl_NumUtfChars(bytes, numBytes);
-    unicode = (Tcl_UniChar *)Tcl_UtfToUniCharDString(bytes, numBytes, &dsPtr);
+    if (bytes) {
+	numChars = Tcl_NumUtfChars(bytes, numBytes);
+	unicode = (Tcl_UniChar *) Tcl_UtfToUniCharDString(bytes, numBytes,
+		&dsPtr);
+    }
     AppendUnicodeToUnicodeRep(objPtr, unicode, numChars);
     Tcl_DStringFree(&dsPtr);
 }
@@ -1547,7 +1554,7 @@ AppendUtfToUtfRep(
 	 * due to the reallocs below.
 	 */
 	int offset = -1;
-	if (bytes >= objPtr->bytes
+	if (bytes && bytes >= objPtr->bytes
 		&& bytes <= objPtr->bytes + objPtr->length) {
 	    offset = bytes - objPtr->bytes;
 	}
@@ -1585,7 +1592,9 @@ AppendUtfToUtfRep(
     stringPtr->numChars = -1;
     stringPtr->hasUnicode = 0;
 
-    memcpy(objPtr->bytes + oldLength, bytes, (size_t) numBytes);
+    if (bytes) {
+	memcpy(objPtr->bytes + oldLength, bytes, (size_t) numBytes);
+    }
     objPtr->bytes[newLength] = 0;
     objPtr->length = newLength;
 }
@@ -2702,6 +2711,38 @@ 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.
diff --git a/generic/tclStubInit.c b/generic/tclStubInit.c
index 99f3e4b..6499bc2 100644
--- a/generic/tclStubInit.c
+++ b/generic/tclStubInit.c
@@ -33,6 +33,9 @@
 #undef Tcl_CreateHashEntry
 #undef TclpGetPid
 #undef TclSockMinimumBuffers
+#undef TclWinGetServByName
+#undef TclWinGetSockOpt
+#undef TclWinSetSockOpt
 #define TclUnusedStubEntry NULL
 
 /*
@@ -104,7 +107,8 @@ TclpIsAtty(int fd)
     return isatty(fd);
 }
 
-int
+#define TclWinGetPlatformId winGetPlatformId
+static int
 TclWinGetPlatformId()
 {
     /* Don't bother to determine the real platform on cygwin,
@@ -120,27 +124,31 @@ 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;
diff --git a/generic/tclThread.c b/generic/tclThread.c
index 8384107..d6b5bcb 100644
--- a/generic/tclThread.c
+++ b/generic/tclThread.c
@@ -338,8 +338,9 @@ 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.
@@ -354,6 +355,9 @@ void
 TclFinalizeThreadData(void)
 {
     TclpFinalizeThreadDataThread();
+#if defined(TCL_THREADS) && defined(USE_THREAD_ALLOC)
+    TclFinalizeThreadAllocThread();
+#endif
 }
 
 /*
diff --git a/generic/tclThreadAlloc.c b/generic/tclThreadAlloc.c
index 2e74fa7..106e908 100644
--- a/generic/tclThreadAlloc.c
+++ b/generic/tclThreadAlloc.c
@@ -1012,6 +1012,33 @@ 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/tclUtil.c b/generic/tclUtil.c
index 5f4cdae..8c6adfe 100644
--- a/generic/tclUtil.c
+++ b/generic/tclUtil.c
@@ -2334,7 +2334,7 @@ TclStringMatchObj(
 	udata = Tcl_GetUnicodeFromObj(strObj, &length);
 	uptn  = Tcl_GetUnicodeFromObj(ptnObj, &plen);
 	match = TclUniCharMatch(udata, length, uptn, plen, flags);
-    } else if ((strObj->typePtr == &tclByteArrayType) && !flags) {
+    } else if (TclIsPureByteArray(strObj) && !flags) {
 	unsigned char *data, *ptn;
 
 	data = Tcl_GetByteArrayFromObj(strObj, &length);
diff --git a/tests/chanio.test b/tests/chanio.test
index b195f7b..2f2540e 100644
--- a/tests/chanio.test
+++ b/tests/chanio.test
@@ -41,7 +41,7 @@ namespace eval ::tcl::test::io {
 
     # You need a *very* special environment to do some tests.  In
     # particular, many file systems do not support large-files...
-    testConstraint largefileSupport 0
+    testConstraint largefileSupport [expr {$::tcl_platform(os) ne "Darwin"}]
 
     # some tests can only be run is umask is 2
     # if "umask" cannot be run, the tests will be skipped.
@@ -4427,10 +4427,10 @@ test chan-io-34.21 {Tcl_Seek and Tcl_Tell on large files} {largefileSupport} {
     chan puts -nonewline $f abcdef
     lappend l [chan tell $f]
     chan close $f
-    lappend l [file size $f]
+    lappend l [file size $path(test3)]
     # truncate...
     chan close [open $path(test3) w]
-    lappend l [file size $f]
+    lappend l [file size $path(test3)]
     set l
 } {0 6 6 4294967296 4294967302 4294967302 0}
 
diff --git a/tests/clock.test b/tests/clock.test
index fea1fc9..7d62a60 100644
--- a/tests/clock.test
+++ b/tests/clock.test
@@ -36927,6 +36927,15 @@ test clock-67.1 {clock format, %% with a letter following [Bug 2819334]} {
     clock format [clock seconds] -format %%r
 } %r
 
+test clock-67.2 {Bug d19a30db57} -body {
+    # error, not segfault
+    tcl::clock::GetJulianDayFromEraYearMonthDay {} 2361222
+} -returnCodes error -match glob -result *
+test clock-67.3 {Bug d19a30db57} -body {
+    # error, not segfault
+    tcl::clock::GetJulianDayFromEraYearWeekDay {} 2361222
+} -returnCodes error -match glob -result *
+
 # cleanup
 
 namespace delete ::testClock
diff --git a/tests/cmdAH.test b/tests/cmdAH.test
index dc61ac6..4ca90c6 100644
--- a/tests/cmdAH.test
+++ b/tests/cmdAH.test
@@ -104,6 +104,9 @@ test cmdAH-2.6.1 {Tcl_CdObjCmd} {
     list [catch {cd ""} msg] $msg
 } {1 {couldn't change working directory to "": no such file or directory}}
 
+test cmdAH-2.6.3 {Tcl_CdObjCmd, bug #3118489} -returnCodes error -body {
+    cd .\0
+} -result "couldn't change working directory to \".\0\": no such file or directory"
 test cmdAH-2.7 {Tcl_ConcatObjCmd} {
     concat
 } {}
diff --git a/tests/io.test b/tests/io.test
index 4791280..f1248b9 100644
--- a/tests/io.test
+++ b/tests/io.test
@@ -41,7 +41,7 @@ testConstraint testthread       [llength [info commands testthread]]
 
 # You need a *very* special environment to do some tests.  In
 # particular, many file systems do not support large-files...
-testConstraint largefileSupport 0
+testConstraint largefileSupport [expr {$::tcl_platform(os) ne "Darwin"}]
 
 # some tests can only be run is umask is 2
 # if "umask" cannot be run, the tests will be skipped.
@@ -1559,6 +1559,45 @@ test io-13.8 {TranslateInputEOL: auto mode: \r\n} {
     close $f
     set x
 } "abcd\ndef"
+test io-13.8.1 {TranslateInputEOL: auto mode: \r\n} {
+    set f [open $path(test1) w]
+    fconfigure $f -translation lf
+    puts -nonewline $f "abcd\r\ndef"
+    close $f
+    set f [open $path(test1)]
+    fconfigure $f -translation auto
+    set x {}
+    lappend x [read $f 5]
+    lappend x [read $f]
+    close $f
+    set x
+} [list "abcd\n" "def"]
+test io-13.8.2 {TranslateInputEOL: auto mode: \r\n} {
+    set f [open $path(test1) w]
+    fconfigure $f -translation lf
+    puts -nonewline $f "abcd\r\ndef"
+    close $f
+    set f [open $path(test1)]
+    fconfigure $f -translation auto -buffersize 6
+    set x {}
+    lappend x [read $f 5]
+    lappend x [read $f]
+    close $f
+    set x
+} [list "abcd\n" "def"]
+test io-13.8.3 {TranslateInputEOL: auto mode: \r\n} {
+    set f [open $path(test1) w]
+    fconfigure $f -translation lf
+    puts -nonewline $f "abcd\r\n\r\ndef"
+    close $f
+    set f [open $path(test1)]
+    fconfigure $f -translation auto -buffersize 7
+    set x {}
+    lappend x [read $f 5]
+    lappend x [read $f]
+    close $f
+    set x
+} [list "abcd\n" "\ndef"]
 test io-13.9 {TranslateInputEOL: auto mode: \r followed by not \n} {
     set f [open $path(test1) w]
     fconfigure $f -translation lf
@@ -2747,7 +2786,7 @@ test io-29.34 {Tcl_Close, async flush on close, using sockets} {socket tempNotMa
     variable x running
     set l abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz
     proc writelots {s l} {
-	for {set i 0} {$i < 2000} {incr i} {
+	for {set i 0} {$i < 9000} {incr i} {
 	    puts $s $l
 	}
     }
@@ -2778,7 +2817,7 @@ test io-29.34 {Tcl_Close, async flush on close, using sockets} {socket tempNotMa
     close $ss
     vwait [namespace which -variable x]
     set c
-} 2000
+} 9000
 test io-29.35 {Tcl_Close vs fileevent vs multiple interpreters} {socket tempNotMac fileevent} {
     # On Mac, this test screws up sockets such that subsequent tests using port 2828
     # either cause errors or panic().
@@ -3960,6 +3999,46 @@ test io-32.11 {Tcl_Read from a pipe} {stdio openpipe} {
 } {{hello
 } {hello
 }}
+test io-32.11.1 {Tcl_Read from a pipe} {stdio openpipe} {
+    file delete $path(pipe)
+    set f1 [open $path(pipe) w]
+    puts $f1 {chan configure stdout -translation crlf}
+    puts $f1 {puts [gets stdin]}
+    puts $f1 {puts [gets stdin]}
+    close $f1
+    set f1 [open "|[list [interpreter] $path(pipe)]" r+]
+    puts $f1 hello
+    flush $f1
+    set x ""
+    lappend x [read $f1 6]
+    puts $f1 hello
+    flush $f1
+    lappend x [read $f1]
+    close $f1
+    set x
+} {{hello
+} {hello
+}}
+test io-32.11.1 {Tcl_Read from a pipe} {stdio openpipe} {
+    file delete $path(pipe)
+    set f1 [open $path(pipe) w]
+    puts $f1 {chan configure stdout -translation crlf}
+    puts $f1 {puts [gets stdin]}
+    puts $f1 {puts [gets stdin]}
+    close $f1
+    set f1 [open "|[list [interpreter] $path(pipe)]" r+]
+    puts $f1 hello
+    flush $f1
+    set x ""
+    lappend x [read $f1 6]
+    puts $f1 hello
+    flush $f1
+    lappend x [read $f1]
+    close $f1
+    set x
+} {{hello
+} {hello
+}}
 test io-32.12 {Tcl_Read, -nonewline} {
     file delete $path(test1)
     set f1 [open $path(test1) w]
@@ -4433,10 +4512,10 @@ test io-34.21 {Tcl_Seek and Tcl_Tell on large files} {largefileSupport} {
     puts -nonewline $f abcdef
     lappend l [tell $f]
     close $f
-    lappend l [file size $f]
+    lappend l [file size $path(test3)]
     # truncate...
     close [open $path(test3) w]
-    lappend l [file size $f]
+    lappend l [file size $path(test3)]
     set l
 } {0 6 6 4294967296 4294967302 4294967302 0}
 
@@ -4729,7 +4808,7 @@ test io-35.18a {Tcl_Eof, eof char, cr write, crlf read} -body {
     close $f
     list $s $l $e [scan [string index $in end] %c]
 } -result {9 8 1 13}
-test io-35.18b {Tcl_Eof, eof char, cr write, crlf read} -constraints knownBug -body {
+test io-35.18b {Tcl_Eof, eof char, cr write, crlf read} -body {
     file delete $path(test1)
     set f [open $path(test1) w]
     fconfigure $f -translation cr -eofchar \x1a
@@ -4772,6 +4851,21 @@ test io-35.19 {Tcl_Eof, eof char in middle, cr write, crlf read} -body {
     close $f
     list $c $l $e [scan [string index $in end] %c]
 } -result {17 8 1 13}
+test io-35.20 {Tcl_Eof, eof char in middle, cr write, crlf read} {
+    file delete $path(test1)
+    set f [open $path(test1) w]
+    fconfigure $f -translation cr -eofchar {}
+    set i [format \n%cqrsuvw 26]
+    puts $f $i
+    close $f
+    set c [file size $path(test1)]
+    set f [open $path(test1) r]
+    fconfigure $f -translation crlf -eofchar \x1a
+    set l [string length [set in [read $f]]]
+    set e [eof $f]
+    close $f
+    list $c $l $e [scan [string index $in end] %c]
+} {9 1 1 13}
 
 # Test Tcl_InputBlocked
 
@@ -6611,11 +6705,23 @@ test io-52.4 {TclCopyChannel} {fcopy} {
     fconfigure $f1 -translation lf -blocking 0
     fconfigure $f2 -translation cr -blocking 0
     fcopy $f1 $f2 -size 40
-    set result [list [fconfigure $f1 -blocking] [fconfigure $f2 -blocking]]
+    set result [list [fblocked $f1] [fconfigure $f1 -blocking] [fconfigure $f2 -blocking]]
+    close $f1
+    close $f2
+    lappend result [file size $path(test1)]
+} {0 0 0 40}
+test io-52.4.1 {TclCopyChannel} {fcopy} {
+    file delete $path(test1)
+    set f1 [open $thisScript]
+    set f2 [open $path(test1) w]
+    fconfigure $f1 -translation lf -blocking 0 -buffersize 10000000
+    fconfigure $f2 -translation cr -blocking 0
+    fcopy $f1 $f2 -size 40
+    set result [list [fblocked $f1] [fconfigure $f1 -blocking] [fconfigure $f2 -blocking]]
     close $f1
     close $f2
     lappend result [file size $path(test1)]
-} {0 0 40}
+} {0 0 0 40}
 test io-52.5 {TclCopyChannel, all} {fcopy} {
     file delete $path(test1)
     set f1 [open $thisScript]
@@ -6801,6 +6907,150 @@ test io-52.11 {TclCopyChannel & encodings} {fcopy} {
     file size $path(kyrillic.txt)
 } 3
 
+test io-52.12 {coverage of -translation auto} {
+    file delete $path(test1) $path(test2)
+    set out [open $path(test1) wb]
+    chan configure $out -translation lf
+    puts -nonewline $out abcdefg\rhijklmn\nopqrstu\r\nvwxyz
+    close $out
+    set in [open $path(test1)]
+    chan configure $in -buffersize 8
+    set out [open $path(test2) w]
+    chan configure $out -translation lf
+    fcopy $in $out
+    close $in
+    close $out
+    file size $path(test2)
+} 29
+test io-52.13 {coverage of -translation cr} {
+    file delete $path(test1) $path(test2)
+    set out [open $path(test1) wb]
+    chan configure $out -translation lf
+    puts -nonewline $out abcdefg\rhijklmn\nopqrstu\r\nvwxyz
+    close $out
+    set in [open $path(test1)]
+    chan configure $in -buffersize 8 -translation cr
+    set out [open $path(test2) w]
+    chan configure $out -translation lf
+    fcopy $in $out
+    close $in
+    close $out
+    file size $path(test2)
+} 30
+test io-52.14 {coverage of -translation crlf} {
+    file delete $path(test1) $path(test2)
+    set out [open $path(test1) wb]
+    chan configure $out -translation lf
+    puts -nonewline $out abcdefg\rhijklmn\nopqrstu\r\nvwxyz
+    close $out
+    set in [open $path(test1)]
+    chan configure $in -buffersize 8 -translation crlf
+    set out [open $path(test2) w]
+    chan configure $out -translation lf
+    fcopy $in $out
+    close $in
+    close $out
+    file size $path(test2)
+} 29
+test io-52.14.1 {coverage of -translation crlf} {
+    file delete $path(test1) $path(test2)
+    set out [open $path(test1) wb]
+    chan configure $out -translation lf
+    puts -nonewline $out abcdefg\rhijklmn\nopqrstu\r\nvwxyz
+    close $out
+    set in [open $path(test1)]
+    chan configure $in -buffersize 8 -translation crlf
+    set out [open $path(test2) w]
+    fcopy $in $out -size 2
+    close $in
+    close $out
+    file size $path(test2)
+} 2
+test io-52.14.2 {coverage of -translation crlf} {
+    file delete $path(test1) $path(test2)
+    set out [open $path(test1) wb]
+    chan configure $out -translation lf
+    puts -nonewline $out abcdefg\rhijklmn\nopqrstu\r\nvwxyz
+    close $out
+    set in [open $path(test1)]
+    chan configure $in -translation crlf
+    set out [open $path(test2) w]
+    fcopy $in $out -size 9
+    close $in
+    close $out
+    file size $path(test2)
+} 9
+test io-52.15 {coverage of -translation crlf} {
+    file delete $path(test1) $path(test2)
+    set out [open $path(test1) wb]
+    chan configure $out -translation lf
+    puts -nonewline $out abcdefg\r
+    close $out
+    set in [open $path(test1)]
+    chan configure $in -buffersize 8 -translation crlf
+    set out [open $path(test2) w]
+    fcopy $in $out
+    close $in
+    close $out
+    file size $path(test2)
+} 8
+test io-52.16 {coverage of eofChar handling} {
+    file delete $path(test1) $path(test2)
+    set out [open $path(test1) wb]
+    chan configure $out -translation lf
+    puts -nonewline $out abcdefg\rhijklmn\nopqrstu\r\nvwxyz
+    close $out
+    set in [open $path(test1)]
+    chan configure $in -buffersize 8 -translation lf -eofchar a
+    set out [open $path(test2) w]
+    fcopy $in $out
+    close $in
+    close $out
+    file size $path(test2)
+} 0
+test io-52.17 {coverage of eofChar handling} {
+    file delete $path(test1) $path(test2)
+    set out [open $path(test1) wb]
+    chan configure $out -translation lf
+    puts -nonewline $out abcdefg\rhijklmn\nopqrstu\r\nvwxyz
+    close $out
+    set in [open $path(test1)]
+    chan configure $in -buffersize 8 -translation lf -eofchar d
+    set out [open $path(test2) w]
+    fcopy $in $out
+    close $in
+    close $out
+    file size $path(test2)
+} 3
+test io-52.18 {coverage of eofChar handling} {
+    file delete $path(test1) $path(test2)
+    set out [open $path(test1) wb]
+    chan configure $out -translation lf
+    puts -nonewline $out abcdefg\rhijklmn\nopqrstu\r\nvwxyz
+    close $out
+    set in [open $path(test1)]
+    chan configure $in -buffersize 8 -translation crlf -eofchar h
+    set out [open $path(test2) w]
+    fcopy $in $out
+    close $in
+    close $out
+    file size $path(test2)
+} 8
+test io-52.19 {coverage of eofChar handling} {
+    file delete $path(test1) $path(test2)
+    set out [open $path(test1) wb]
+    chan configure $out -translation lf
+    puts -nonewline $out abcdefg\rhijklmn\nopqrstu\r\nvwxyz
+    close $out
+    set in [open $path(test1)]
+    chan configure $in -buffersize 10 -translation crlf -eofchar h
+    set out [open $path(test2) w]
+    fcopy $in $out
+    close $in
+    close $out
+    file size $path(test2)
+} 8
+
 test io-53.1 {CopyData} {fcopy} {
     file delete $path(test1)
     set f1 [open $thisScript]
@@ -6870,17 +7120,17 @@ test io-53.4 {CopyData: background write overflow} {stdio unix openpipe fileeven
     for {set x 0} {$x < 12} {incr x} {
 	append big $big
     }
-    file delete $path(test1)
+#    file delete $path(test1)
     file delete $path(pipe)
     set f1 [open $path(pipe) w]
     puts $f1 {
 	puts ready
 	fcopy stdin stdout -command { set x }
 	vwait x
-	set f [open $path(test1) w]
-	fconfigure $f -translation lf
-	puts $f "done"
-	close $f
+#	set f [open $path(test1) w]
+#	fconfigure $f -translation lf
+#	puts $f "done"
+#	close $f
     }
     close $f1
     set f1 [open "|[list [interpreter] $path(pipe)]" r+]
diff --git a/tests/ioCmd.test b/tests/ioCmd.test
index 768a748..5a76d48 100644
--- a/tests/ioCmd.test
+++ b/tests/ioCmd.test
@@ -755,6 +755,90 @@ test iocmd-21.19 {chan create, init failure -> no channel, no finalize} -match g
     rename foo {}
     set res
 } -result {{} {initialize rc* {read write}} 1 {*all required methods*} {}}
+test iocmd-21.20 {Bug 88aef05cda} -setup {
+    proc foo {method chan args} {
+	switch -- $method blocking {
+	    chan configure $chan -blocking [lindex $args 0]
+	    return
+	} initialize {
+	    return {initialize finalize watch blocking read write
+		    configure cget cgetall}
+	} finalize {
+	    return
+	}
+    }
+    set ch [chan create {read write} foo]
+} -body {
+    list [catch {chan configure $ch -blocking 0} m] $m
+} -cleanup {
+    close $ch
+    rename foo {}
+} -match glob -result {1 {*nested eval*}}
+test iocmd-21.21 {[close] in [read] segfaults} -setup {
+    proc foo {method chan args} {
+	switch -- $method initialize {
+	    return {initialize finalize watch read}
+	} finalize {} watch {} read {
+	    close $chan
+	    return a
+	}
+    }
+    set ch [chan create read foo]
+} -body {
+    read $ch 0
+} -cleanup {
+    close $ch
+    rename foo {}
+} -result {}
+test iocmd-21.22 {[close] in [read] segfaults} -setup {
+    proc foo {method chan args} {
+	switch -- $method initialize {
+	    return {initialize finalize watch read}
+	} finalize {} watch {} read {
+	    catch {close $chan}
+	    return a
+	}
+    }
+    set ch [chan create read foo]
+} -body {
+    read $ch 1
+} -returnCodes error -cleanup {
+    catch {close $ch}
+    rename foo {}
+} -match glob -result {*invalid argument*}
+test iocmd-21.23 {[close] in [gets] segfaults} -setup {
+    proc foo {method chan args} {
+	switch -- $method initialize {
+	    return {initialize finalize watch read}
+	} finalize {} watch {} read {
+	    catch {close $chan}
+	    return \n
+	}
+    }
+    set ch [chan create read foo]
+} -body {
+    gets $ch
+} -cleanup {
+    catch {close $ch}
+    rename foo {}
+} -result {}
+test iocmd-21.24 {[close] in binary [gets] segfaults} -setup {
+    proc foo {method chan args} {
+	switch -- $method initialize {
+	    return {initialize finalize watch read}
+	} finalize {} watch {} read {
+	    catch {close $chan}
+	    return \n
+	}
+    }
+    set ch [chan create read foo]
+} -body {
+    chan configure $ch -translation binary
+    gets $ch
+} -cleanup {
+    catch {close $ch}
+    rename foo {}
+} -result {}
 
 # --- --- --- --------- --------- ---------
 # Helper commands to record the arguments to handler methods.
@@ -1013,6 +1097,20 @@ test iocmd-23.10 {chan read, EAGAIN means no data, yet no eof either} -match glo
     rename foo {}
     unset res
 } -result {{read rc* 4096} {} 0}
+test iocmd-23.11 {chan read, close pulls the rug out} -match glob -body {
+    set res {}
+    proc foo {args} {
+	oninit; onfinal; track
+	set args [lassign $args sub id]
+	if {$sub ne "read"} {return}
+	close $id
+	return {}
+    }
+    set c [chan create {r} foo]
+    note [read $c]
+    rename foo {}
+    set res
+} -result {{read rc* 4096} {}}
 
 # --- === *** ###########################
 # method write
@@ -1940,13 +2038,13 @@ test iocmd-32.1 {origin interpreter of moved channel destroyed during access} -m
 	proc foo {args} {
 	    oninit; onfinal; track;
 	    # destroy interpreter during channel access
-	    # Actually not possible for an interp to destroy itself.
-	    interp delete {}
-	    return}
+	    suicide
+	}
 	set chan [chan create {r w} foo]
 	fconfigure $chan -buffering none
 	set chan
     }]
+    interp alias $ida suicide {} interp delete $ida
 
     # Move channel to 2nd thread.
     interp eval $ida [list testchannel cut    $chan]
@@ -1965,8 +2063,7 @@ test iocmd-32.1 {origin interpreter of moved channel destroyed during access} -m
 	set res
     }]
     set res
-} -constraints {testchannel impossible} \
-    -result {Owner lost}
+} -constraints {testchannel} -result {Owner lost}
 
 test iocmd-32.2 {delete interp of reflected chan} {
     # Bug 3034840
diff --git a/tests/iogt.test b/tests/iogt.test
index 3882ecc..5fe3dc2 100644
--- a/tests/iogt.test
+++ b/tests/iogt.test
@@ -159,8 +159,8 @@ proc fevent {fdelay idelay blocks script data} {
 
     #puts stdout ">>>>>" ; flush stdout
 
-    uplevel #0 set sock $sk
-    set res [uplevel #0 $script]
+    uplevel 1 set sock $sk
+    set res [uplevel 1 $script]
 
     catch {close $sk}
     return $res
@@ -242,6 +242,36 @@ proc id_fulltrail {var op data} {
     return $res
 }
 
+proc id_torture {chan op data} {
+    switch -- $op {
+	create/write -
+	create/read  -
+	delete/write -
+	delete/read  -
+	clear_read   {;#ignore}
+	flush/write -
+	flush/read  {}
+	write       {
+	    global level
+	    if {$level} {
+		return
+	    }
+	    incr level
+	    testchannel unstack $chan
+	    testchannel transform $chan \
+		-command [namespace code [list id_torture $chan]]
+	    return $data
+	}
+	read        {
+	    testchannel unstack $chan
+	    testchannel transform $chan \
+		-command [namespace code [list id_torture $chan]]
+	    return $data
+	}
+	query/maxRead {return -1}
+    }
+}
+
 proc counter {var op data} {
     variable $var
     upvar 0 $var n
@@ -364,6 +394,10 @@ proc audit_flow {var -attach channel} {
     testchannel transform $channel -command [namespace code [list id_fulltrail $var]]
 }
 
+proc torture {-attach channel} {
+    testchannel transform $channel -command [namespace code [list id_torture $channel]]
+}
+
 proc stopafter {var n -attach channel} {
     variable $var
     upvar 0 $var vn
@@ -518,6 +552,7 @@ query/maxRead
 read
 query/maxRead
 flush/read
+query/maxRead
 delete/read
 --------
 create/write
@@ -570,6 +605,7 @@ read {
 }
 query/maxRead {} -1
 flush/read {} {}
+query/maxRead {} -1
 delete/read {} *ignored*
 --------
 create/write {} *ignored*
@@ -624,6 +660,7 @@ read {%^&*()_+-=
 }
 query/maxRead {} -1
 flush/read {} {}
+query/maxRead {} -1
 write %^&*()_+-= %^&*()_+-=
 write {
 } {
@@ -632,9 +669,27 @@ delete/read {} *ignored*
 flush/write {} {}
 delete/write {} *ignored*}
 
+test iogt-2.4 {basic I/O, mixed trail} {testchannel} {
+    set fh [open $path(dummy) r]
+    torture -attach $fh
+    chan configure $fh -buffersize 2
+    set x [read $fh]
+    testchannel unstack $fh
+    close   $fh
+    set x
+} {}
+test iogt-2.5 {basic I/O, mixed trail} {testchannel} {
+    set ::level 0
+    set fh [open $path(dummyout) w]
+    torture -attach $fh
+    puts -nonewline $fh abcdef
+    flush $fh
+    testchannel unstack $fh
+    close   $fh
+} {}
 
 test iogt-3.0 {Tcl_Channel valid after stack/unstack, fevent handling} \
-	{testchannel unknownFailure} {
+	{testchannel knownBug} {
     # This test to check the validity of aquired Tcl_Channel references is
     # not possible because even a backgrounded fcopy will immediately start
     # to copy data, without waiting for the event loop. This is done only in
@@ -651,6 +706,7 @@ test iogt-3.0 {Tcl_Channel valid after stack/unstack, fevent handling} \
     set fin  [open $path(dummy) r]
 
     fevent 1000 500 {20 20 20 10 1 1} {
+	variable copy
 	close $fin
 
 	set          fout [open dummyout w]
@@ -688,7 +744,7 @@ test iogt-3.0 {Tcl_Channel valid after stack/unstack, fevent handling} \
 } {1 {create/write create/read write flush/write flush/read delete/write delete/read}}
 
 
-test iogt-4.0 {fileevent readable, after transform} {testchannel unknownFailure} {
+test iogt-4.0 {fileevent readable, after transform} {testchannel knownBug} {
     set fin  [open $path(dummy) r]
     set data [read $fin]
     close $fin
@@ -718,10 +774,11 @@ test iogt-4.0 {fileevent readable, after transform} {testchannel unknownFailure}
     }
 
     fevent 1000 500 {20 20 20 10 1} {
+	variable stop
 	audit_flow trail   -attach $sock
 	rblocks_t  rbuf trail 23 -attach $sock
 
-	fileevent $sock readable [list Get $sock]
+	fileevent $sock readable [namespace code [list Get $sock]]
 
 	flush $sock ; # now, or fcopy will error us out
 	# But the 1 second delay should be enough to
@@ -819,7 +876,7 @@ delete/write {} *ignored*
 delete/read {} *ignored*}  ; # catch unescaped quote "
 
 
-test iogt-5.0 {EOF simulation} {testchannel unknownFailure} {
+test iogt-5.0 {EOF simulation} {testchannel knownBug} {
     set fin  [open $path(dummy)    r]
     set fout [open $path(dummyout) w]
 
@@ -916,6 +973,15 @@ test iogt-6.0 {Push back} testchannel {
 } {xxx}
 
 test iogt-6.1 {Push back and up} {testchannel knownBug} {
+
+    # This test demonstrates the bug/misfeature in the stacked
+    # channel implementation that data can be discarded if it is
+    # read into the buffers of one channel in the stack, and then
+    # that channel is popped before anything above it reads.
+    #
+    # This bug can be worked around by always setting -buffersize
+    # to 1, but who wants to do that?
+
     set f [open $path(dummy) r]
 
     # contents of dummy = "abcdefghi..."
diff --git a/tests/socket.test b/tests/socket.test
index 218cce4..1b7c5fa 100644
--- a/tests/socket.test
+++ b/tests/socket.test
@@ -67,6 +67,10 @@ namespace import -force ::tcltest::*
 testConstraint testthread [llength [info commands testthread]]
 testConstraint exec [llength [info commands exec]]
 
+# Produce a random port number in the Dynamic/Private range
+# from 49152 through 65535.
+proc randport {} { expr {int(rand()*16383+49152)} }
+
 # If remoteServerIP or remoteServerPort are not set, check in the
 # environment variables for externally set values.
 #
@@ -910,22 +914,6 @@ test socket-8.1 {testing -async flag on sockets} {socket} {
     set z
 } bye
 
-test socket-8.2 {testing writable event when quick failure} {socket win} {
-    # Test for bug 336441ed59 where a quick background fail was ignored
-
-    # Test only for windows as socket -async 255.255.255.255 fails directly
-    # on unix
-    
-    # The following connect should fail very quickly
-    set a1 [after 2000 {set x timeout}]
-    set s [socket -async 255.255.255.255 43434]
-    fileevent $s writable {set x writable}
-    vwait x
-    catch {close $s}
-    after cancel $a1
-    set x
-} writable
-
 test socket-9.1 {testing spurious events} {socket} {
     set len 0
     set spurious 0
@@ -1699,6 +1687,37 @@ if {[string match sock* $commandSocket] == 1} {
 }
 catch {close $commandSocket}
 catch {close $remoteProcChan}
+test socket-14.13 {testing writable event when quick failure} -constraints {socket win supported_inet} -body {
+    # Test for bug 336441ed59 where a quick background fail was ignored
+    
+    # Test only for windows as socket -async 255.255.255.255 fails
+    # directly on unix
+    
+    # The following connect should fail very quickly
+    set a1 [after 2000 {set x timeout}]
+    set s [socket -async 255.255.255.255 43434]
+    fileevent $s writable {set x writable}
+    vwait x
+    set x
+} -cleanup {
+    catch {close $s}
+    after cancel $a1
+} -result writable
+
+test socket-14.14 {testing fileevent readable on failed async socket connect} -constraints [list socket] -body {
+    # Test for bug 581937ab1e
+    
+    set a1 [after 5000 {set x timeout}]
+    # This connect should fail
+    set s [socket -async localhost [randport]]
+    fileevent $s readable {set x readable}
+    vwait x
+    set x
+} -cleanup {
+    catch {close $s}
+    after cancel $a1
+} -result readable
+
 ::tcltest::cleanupTests
 flush stdout
 return
diff --git a/unix/Makefile.in b/unix/Makefile.in
index c7caf5b..746abde 100644
--- a/unix/Makefile.in
+++ b/unix/Makefile.in
@@ -736,6 +736,9 @@ install-binaries: binaries
 	    @INSTALL_STUB_LIB@ ; \
 	fi
 	@EXTRA_INSTALL_BINARIES@
+	@echo "Installing pkg-config file to $(LIB_INSTALL_DIR)/pkgconfig/"
+	@mkdir -p $(LIB_INSTALL_DIR)/pkgconfig
+	@$(INSTALL_DATA) tcl.pc $(LIB_INSTALL_DIR)/pkgconfig/tcl.pc
 
 install-libraries: libraries $(INSTALL_TZDATA) install-msgs
 	@for i in "$(INCLUDE_INSTALL_DIR)" "$(SCRIPT_INSTALL_DIR)"; \
@@ -905,7 +908,8 @@ clean:
 
 distclean: clean
 	rm -rf Makefile config.status config.cache config.log tclConfig.sh \
-		$(PACKAGE).* prototype tclConfig.h *.plist Tcl.framework
+		$(PACKAGE).* prototype tclConfig.h *.plist Tcl.framework \
+		tcl.pc
 	cd dltest ; $(MAKE) distclean
 
 depend:
@@ -1657,7 +1661,7 @@ $(UNIX_DIR)/tclConfig.h.in: $(MAC_OSX_DIR)/configure
 	cd $(MAC_OSX_DIR); autoheader; touch $@
 
 EOLFIX=$(NATIVE_TCLSH) $(TOOL_DIR)/eolFix.tcl
-dist: $(UNIX_DIR)/configure $(UNIX_DIR)/tclConfig.h.in $(MAC_OSX_DIR)/configure genstubs
+dist: $(UNIX_DIR)/configure $(UNIX_DIR)/tclConfig.h.in $(UNIX_DIR)/tcl.pc.in $(MAC_OSX_DIR)/configure genstubs
 	rm -rf $(DISTDIR)
 	mkdir -p $(DISTDIR)/unix
 	cp -p $(UNIX_DIR)/*.[ch] $(DISTDIR)/unix
@@ -1668,7 +1672,7 @@ dist: $(UNIX_DIR)/configure $(UNIX_DIR)/tclConfig.h.in $(MAC_OSX_DIR)/configure
 		$(UNIX_DIR)/tclConfig.sh.in $(UNIX_DIR)/install-sh \
 		$(UNIX_DIR)/README $(UNIX_DIR)/ldAix $(UNIX_DIR)/tcl.spec \
 		$(UNIX_DIR)/installManPage $(UNIX_DIR)/tclConfig.h.in \
-		$(DISTDIR)/unix
+		$(UNIX_DIR)/tcl.pc.in $(DISTDIR)/unix
 	chmod 775 $(DISTDIR)/unix/configure $(DISTDIR)/unix/configure.in
 	chmod 775 $(DISTDIR)/unix/ldAix
 	@mkdir $(DISTDIR)/generic
diff --git a/unix/configure b/unix/configure
index 1b2ea41..d268647 100755
--- a/unix/configure
+++ b/unix/configure
@@ -7010,9 +7010,9 @@ echo "$as_me: error: CYGWIN compile is only supported with --enable-threads" >&2
 	    fi
 	    do64bit_ok=yes
 	    if test "x${SHARED_BUILD}" = "x1"; then
-		echo "running cd ../win; ${CONFIG_SHELL-/bin/sh} ./configure $ac_configure_args"
+		echo "running cd ${TCL_SRC_DIR}/win; ${CONFIG_SHELL-/bin/sh} ./configure $ac_configure_args"
 		# The eval makes quoting arguments work.
-		if cd ../win; eval ${CONFIG_SHELL-/bin/sh} ./configure $ac_configure_args; cd ../unix
+		if cd ${TCL_SRC_DIR}/win; eval ${CONFIG_SHELL-/bin/sh} ./configure $ac_configure_args; cd ../unix
 		then :
 		else
 		    { echo "configure: error: configure failed for ../win" 1>&2; exit 1; }
@@ -18915,7 +18915,7 @@ TCL_SHARED_BUILD=${SHARED_BUILD}
 
 
 
-                              ac_config_files="$ac_config_files Makefile:../unix/Makefile.in dltest/Makefile:../unix/dltest/Makefile.in tclConfig.sh:../unix/tclConfig.sh.in"
+                              ac_config_files="$ac_config_files Makefile:../unix/Makefile.in dltest/Makefile:../unix/dltest/Makefile.in tclConfig.sh:../unix/tclConfig.sh.in tcl.pc:../unix/tcl.pc.in"
 
 cat >confcache <<\_ACEOF
 # This file is a shell script that caches the results of configure
@@ -19469,6 +19469,7 @@ do
   "Makefile" ) CONFIG_FILES="$CONFIG_FILES Makefile:../unix/Makefile.in" ;;
   "dltest/Makefile" ) CONFIG_FILES="$CONFIG_FILES dltest/Makefile:../unix/dltest/Makefile.in" ;;
   "tclConfig.sh" ) CONFIG_FILES="$CONFIG_FILES tclConfig.sh:../unix/tclConfig.sh.in" ;;
+  "tcl.pc" ) CONFIG_FILES="$CONFIG_FILES tcl.pc:../unix/tcl.pc.in" ;;
   "Tcl.framework" ) CONFIG_COMMANDS="$CONFIG_COMMANDS Tcl.framework" ;;
   *) { { echo "$as_me:$LINENO: error: invalid argument: $ac_config_target" >&5
 echo "$as_me: error: invalid argument: $ac_config_target" >&2;}
diff --git a/unix/configure.in b/unix/configure.in
index b5a09dd..318bcf8 100644
--- a/unix/configure.in
+++ b/unix/configure.in
@@ -940,5 +940,6 @@ AC_CONFIG_FILES([
     Makefile:../unix/Makefile.in
     dltest/Makefile:../unix/dltest/Makefile.in
     tclConfig.sh:../unix/tclConfig.sh.in
+    tcl.pc:../unix/tcl.pc.in
 ])
 AC_OUTPUT
diff --git a/unix/tcl.m4 b/unix/tcl.m4
index 10408a8..b6c86b6 100644
--- a/unix/tcl.m4
+++ b/unix/tcl.m4
@@ -1266,9 +1266,9 @@ AC_DEFUN([SC_CONFIG_CFLAGS], [
 	    fi
 	    do64bit_ok=yes
 	    if test "x${SHARED_BUILD}" = "x1"; then
-		echo "running cd ../win; ${CONFIG_SHELL-/bin/sh} ./configure $ac_configure_args"
+		echo "running cd ${TCL_SRC_DIR}/win; ${CONFIG_SHELL-/bin/sh} ./configure $ac_configure_args"
 		# The eval makes quoting arguments work.
-		if cd ../win; eval ${CONFIG_SHELL-/bin/sh} ./configure $ac_configure_args; cd ../unix
+		if cd ${TCL_SRC_DIR}/win; eval ${CONFIG_SHELL-/bin/sh} ./configure $ac_configure_args; cd ../unix
 		then :
 		else
 		    { echo "configure: error: configure failed for ../win" 1>&2; exit 1; }
diff --git a/unix/tcl.pc.in b/unix/tcl.pc.in
new file mode 100644
index 0000000..b750300
--- /dev/null
+++ b/unix/tcl.pc.in
@@ -0,0 +1,14 @@
+# tcl pkg-config source file
+
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: Tool Command Language
+Description: Tcl is a powerful, easy-to-learn dynamic programming language, suitable for a wide range of uses.
+URL: http://www.tcl.tk/
+Version: @TCL_VERSION@@TCL_PATCH_LEVEL@
+Libs: -L${libdir} @TCL_LIB_FLAG@
+Libs.private: @TCL_LIBS@
+Cflags: -I${includedir}
diff --git a/unix/tclUnixFile.c b/unix/tclUnixFile.c
index 29f1aba..c5f75a7 100644
--- a/unix/tclUnixFile.c
+++ b/unix/tclUnixFile.c
@@ -1111,6 +1111,12 @@ TclNativeCreateNativeRep(
     str = Tcl_GetStringFromObj(validPathPtr, &len);
     Tcl_UtfToExternalDString(NULL, str, len, &ds);
     len = Tcl_DStringLength(&ds) + sizeof(char);
+    if (strlen(Tcl_DStringValue(&ds)) < len - sizeof(char)) {
+	/* See bug [3118489]: NUL in filenames */
+	Tcl_DecrRefCount(validPathPtr);
+	Tcl_DStringFree(&ds);
+	return NULL;
+    }
     Tcl_DecrRefCount(validPathPtr);
     nativePathPtr = ckalloc((unsigned) len);
     memcpy((void*)nativePathPtr, (void*)Tcl_DStringValue(&ds), (size_t) len);
diff --git a/unix/tclUnixThrd.c b/unix/tclUnixThrd.c
index ad36242..d30791d 100644
--- a/unix/tclUnixThrd.c
+++ b/unix/tclUnixThrd.c
@@ -814,6 +814,7 @@ TclpFreeAllocCache(
 	 */
 
 	TclFreeAllocCache(ptr);
+	pthread_setspecific(key, NULL);
 
     } else if (initialized) {
 	/*
diff --git a/win/tclWinFCmd.c b/win/tclWinFCmd.c
index 8999831..441337e 100644
--- a/win/tclWinFCmd.c
+++ b/win/tclWinFCmd.c
@@ -1156,7 +1156,12 @@ DoRemoveJustDirectory(
 
   end:
     if (errorPtr != NULL) {
+	char *p;
 	Tcl_WinTCharToUtf(nativePath, -1, errorPtr);
+	p = Tcl_DStringValue(errorPtr);
+	for (; *p; ++p) {
+	    if (*p == '\\') *p = '/';
+	}
     }
     return TCL_ERROR;
 
diff --git a/win/tclWinFile.c b/win/tclWinFile.c
index 676c443..9bf63b1 100644
--- a/win/tclWinFile.c
+++ b/win/tclWinFile.c
@@ -1856,6 +1856,9 @@ TclpObjChdir(
 
     nativePath = (const TCHAR *) Tcl_FSGetNativePath(pathPtr);
 
+    if (!nativePath) {
+	return -1;
+    }
     result = (*tclWinProcs->setCurrentDirectoryProc)(nativePath);
 
     if (result == 0) {
@@ -3197,19 +3200,72 @@ TclNativeCreateNativeRep(
     }
 
     str = Tcl_GetStringFromObj(validPathPtr, &len);
-    if (str[0] == '/' && str[1] == '/' && str[2] == '?' && str[3] == '/') {
-	char *p;
-
-	for (p = str; p && *p; ++p) {
-	    if (*p == '/') {
-		*p = '\\';
-	    }
-	}
-    }
     Tcl_WinUtfToTChar(str, len, &ds);
     if (tclWinProcs->useWide) {
+	WCHAR *wp = (WCHAR *) Tcl_DStringValue(&ds);
+	len = Tcl_DStringLength(&ds)>>1;
+	/*
+	** If path starts with "//?/" or "\\?\" (extended path), translate
+	** any slashes to backslashes but accept the '?' as being valid.
+	*/
+	if ((str[0]=='\\' || str[0]=='/') && (str[1]=='\\' || str[1]=='/')
+		&& str[2]=='?' && (str[3]=='\\' || str[3]=='/')) {
+	    wp[0] = wp[1] = wp[3] = '\\';
+	    str += 4;
+	    wp += 4;
+	    len -= 4;
+	}
+	/*
+	** If there is a drive prefix, the ':' must be considered valid.
+	**/
+	if (((str[0]>='A'&&str[0]<='Z') || (str[0]>='a'&&str[0]<='z'))
+		&& str[1]==':') {
+	    wp += 2;
+	    len -= 2;
+	}
+	while (len-->0) {
+	    if ((*wp < ' ') || wcschr(L"\"*:<>?|", *wp)) {
+		Tcl_DecrRefCount(validPathPtr);
+		Tcl_DStringFree(&ds);
+		return NULL;
+	    } else if (*wp=='/') {
+		*wp = '\\';
+	    }
+	    ++wp;
+	}
 	len = Tcl_DStringLength(&ds) + sizeof(WCHAR);
     } else {
+	char *p = Tcl_DStringValue(&ds);
+	len = Tcl_DStringLength(&ds);
+	/*
+	** If path starts with "//?/" or "\\?\" (extended path), translate
+	** any slashes to backslashes but accept the '?' as being valid.
+	*/
+	if ((str[0]=='\\' || str[0]=='/') && (str[1]=='\\' || str[1]=='/')
+		&& str[2]=='?' && (str[3]=='\\' || str[3]=='/')) {
+	    p[0] = p[1] = p[3] = '\\';
+	    str += 4;
+	    p += 4;
+	    len -= 4;
+	}
+	/*
+	** If there is a drive prefix, the ':' must be considered valid.
+	**/
+	if (((str[0]>='A'&&str[0]<='Z') || (str[0]>='a'&&str[0]<='z'))
+		&& str[1]==':') {
+	    p += 2;
+	    len -= 2;
+	}
+	while (len-->0) {
+	    if ((*p < ' ') || strchr("\"*:<>?|", *p)) {
+		Tcl_DecrRefCount(validPathPtr);
+		Tcl_DStringFree(&ds);
+		return NULL;
+	    } else if (*p=='/') {
+		*p = '\\';
+	    }
+	    ++p;
+	}
 	len = Tcl_DStringLength(&ds) + sizeof(char);
     }
     Tcl_DecrRefCount(validPathPtr);
diff --git a/win/tclWinInit.c b/win/tclWinInit.c
index 2f3c7e8..4e860b2 100644
--- a/win/tclWinInit.c
+++ b/win/tclWinInit.c
@@ -113,8 +113,8 @@ static int		ToUtf(CONST WCHAR *wSrc, char *dst);
  *
  * TclpInitPlatform --
  *
- *	Initialize all the platform-dependant things like signals and
- *	floating-point error handling.
+ *	Initialize all the platform-dependant things like signals,
+ *	floating-point error handling and sockets.
  *
  *	Called at process initialization time.
  *
@@ -130,20 +130,16 @@ static int		ToUtf(CONST WCHAR *wSrc, char *dst);
 void
 TclpInitPlatform(void)
 {
-    tclPlatform = TCL_PLATFORM_WINDOWS;
+    WSADATA wsaData;
+    WORD wVersionRequested = MAKEWORD(2, 2);
 
-    /*
-     * The following code stops Windows 3.X and Windows NT 3.51 from
-     * automatically putting up Sharing Violation dialogs, e.g, when someone
-     * tries to access a file that is locked or a drive with no disk in it.
-     * Tcl already returns the appropriate error to the caller, and they can
-     * decide to put up their own dialog in response to that failure.
-     *
-     * Under 95 and NT 4.0, this is a NOOP because the system doesn't
-     * automatically put up dialogs when the above operations fail.
-     */
+    tclPlatform = TCL_PLATFORM_WINDOWS;
 
-    SetErrorMode(SetErrorMode(0) | SEM_FAILCRITICALERRORS);
+	/*
+	 * Initialize the winsock library. On Windows XP and higher this
+	 * can never fail.
+	 */
+	WSAStartup(wVersionRequested, &wsaData);
 
 #ifdef STATIC_BUILD
     /*
diff --git a/win/tclWinPort.h b/win/tclWinPort.h
index ec9e867..ea6d8f8 100644
--- a/win/tclWinPort.h
+++ b/win/tclWinPort.h
@@ -448,15 +448,6 @@ typedef DWORD_PTR * PDWORD_PTR;
 #define TclpSysRealloc(ptr, size)	((void*)HeapReAlloc(GetProcessHeap(), \
 					    (DWORD)0, (LPVOID)ptr, (DWORD)size))
 
-/*
- * The following defines map from standard socket names to our internal
- * wrappers that redirect through the winSock function table (see the
- * file tclWinSock.c).
- */
-
-#define getservbyname	TclWinGetServByName
-#define getsockopt	TclWinGetSockOpt
-#define setsockopt	TclWinSetSockOpt
 /* This type is not defined in the Windows headers */
 #define socklen_t       int
 
diff --git a/win/tclWinSock.c b/win/tclWinSock.c
index e7b086a..e18a3dd 100644
--- a/win/tclWinSock.c
+++ b/win/tclWinSock.c
@@ -263,8 +263,6 @@ static void
 InitSockets(void)
 {
     DWORD id;
-    WSADATA wsaData;
-    DWORD err;
     ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
 	    TclThreadDataKeyGet(&dataKey);
 
@@ -295,38 +293,6 @@ InitSockets(void)
 	    goto initFailure;
 	}
 
-	/*
-	 * Initialize the winsock library and check the interface version
-	 * actually loaded. We only ask for the 1.1 interface and do require
-	 * that it not be less than 1.1.
-	 */
-
-#define WSA_VERSION_MAJOR 1
-#define WSA_VERSION_MINOR 1
-#define WSA_VERSION_REQD  MAKEWORD(WSA_VERSION_MAJOR, WSA_VERSION_MINOR)
-
-	err = WSAStartup((WORD)WSA_VERSION_REQD, &wsaData);
-	if (err != 0) {
-	    TclWinConvertWSAError(err);
-	    goto initFailure;
-	}
-
-	/*
-	 * Note the byte positions are swapped for the comparison, so that
-	 * 0x0002 (2.0, MAKEWORD(2,0)) doesn't look less than 0x0101 (1.1).
-	 * We want the comparison to be 0x0200 < 0x0101.
-	 */
-
-	if (MAKEWORD(HIBYTE(wsaData.wVersion), LOBYTE(wsaData.wVersion))
-		< MAKEWORD(WSA_VERSION_MINOR, WSA_VERSION_MAJOR)) {
-	    TclWinConvertWSAError(WSAVERNOTSUPPORTED);
-	    WSACleanup();
-	    goto initFailure;
-	}
-
-#undef WSA_VERSION_REQD
-#undef WSA_VERSION_MAJOR
-#undef WSA_VERSION_MINOR
     }
 
     /*
@@ -434,7 +400,6 @@ SocketExitHandler(
 
     TclpFinalizeSockets();
     UnregisterClass("TclSocket", TclWinGetTclInstance());
-    WSACleanup();
     initialized = 0;
     Tcl_MutexUnlock(&socketMutex);
 }
@@ -719,44 +684,52 @@ SocketEventProc(
 	Tcl_SetMaxBlockTime(&blockTime);
 	mask |= TCL_READABLE|TCL_WRITABLE;
     } else if (events & FD_READ) {
-	fd_set readFds;
-	struct timeval timeout;
-
 	/*
-	 * We must check to see if data is really available, since someone
-	 * could have consumed the data in the meantime. Turn off async
-	 * notification so select will work correctly. If the socket is still
-	 * readable, notify the channel driver, otherwise reset the async
-	 * select handler and keep waiting.
+	 * Throw the readable event if an async connect failed.
 	 */
 
-	SendMessage(tsdPtr->hwnd, SOCKET_SELECT,
-		(WPARAM) UNSELECT, (LPARAM) infoPtr);
-
-	FD_ZERO(&readFds);
-	FD_SET(infoPtr->socket, &readFds);
-	timeout.tv_usec = 0;
-	timeout.tv_sec = 0;
+	if (infoPtr->lastError) {
 
-	if (select(0, &readFds, NULL, NULL, &timeout) != 0) {
 	    mask |= TCL_READABLE;
+	    
 	} else {
-	    infoPtr->readyEvents &= ~(FD_READ);
-	    SendMessage(tsdPtr->hwnd, SOCKET_SELECT,
-		    (WPARAM) SELECT, (LPARAM) infoPtr);
-	}
-    }
-    if (events & (FD_WRITE | FD_CONNECT)) {
-	mask |= TCL_WRITABLE;
-	if (events & FD_CONNECT && infoPtr->lastError != NO_ERROR) {
+	    fd_set readFds;
+	    struct timeval timeout;
+
 	    /*
-	     * Connect errors should also fire the readable handler.
+	     * We must check to see if data is really available, since someone
+	     * could have consumed the data in the meantime. Turn off async
+	     * notification so select will work correctly. If the socket is still
+	     * readable, notify the channel driver, otherwise reset the async
+	     * select handler and keep waiting.
 	     */
 
-	    mask |= TCL_READABLE;
+	    SendMessage(tsdPtr->hwnd, SOCKET_SELECT,
+		    (WPARAM) UNSELECT, (LPARAM) infoPtr);
+
+	    FD_ZERO(&readFds);
+	    FD_SET(infoPtr->socket, &readFds);
+	    timeout.tv_usec = 0;
+	    timeout.tv_sec = 0;
+
+	    if (select(0, &readFds, NULL, NULL, &timeout) != 0) {
+		mask |= TCL_READABLE;
+	    } else {
+		infoPtr->readyEvents &= ~(FD_READ);
+		SendMessage(tsdPtr->hwnd, SOCKET_SELECT,
+			(WPARAM) SELECT, (LPARAM) infoPtr);
+	    }
 	}
     }
 
+    /*
+     * writable event
+     */
+
+    if (events & FD_WRITE) {
+	mask |= TCL_WRITABLE;
+    }
+
     if (mask) {
 	Tcl_NotifyChannel(infoPtr->channel, mask);
     }
@@ -2409,19 +2382,18 @@ SocketProc(
 		 */
 
 		if (error != ERROR_SUCCESS) {
+		    /* Async Connect error */
 		    TclWinConvertWSAError((DWORD) error);
 		    infoPtr->lastError = Tcl_GetErrno();
+		    /* Fire also readable event on connect failure */
+		    infoPtr->readyEvents |= FD_READ;
 		}
-	    }
 
-	    if (infoPtr->flags & SOCKET_ASYNC_CONNECT) {
-		infoPtr->flags &= ~(SOCKET_ASYNC_CONNECT);
-		if (error != ERROR_SUCCESS) {
-		    TclWinConvertWSAError((DWORD) error);
-		    infoPtr->lastError = Tcl_GetErrno();
-		}
+		/* fire writable event on connect */
 		infoPtr->readyEvents |= FD_WRITE;
+
 	    }
+
 	    infoPtr->readyEvents |= event;
 
 	    /*
@@ -2557,71 +2529,34 @@ InitializeHostName(
  *----------------------------------------------------------------------
  */
 
+#undef TclWinGetSockOpt
 int
 TclWinGetSockOpt(SOCKET s, int level, int optname, char *optval,
 	int *optlen)
 {
-    /*
-     * Check that WinSock is initialized; do not call it if not, to prevent
-     * system crashes. This can happen at exit time if the exit handler for
-     * WinSock ran before other exit handlers that want to use sockets.
-     */
-
-    if (!SocketsEnabled()) {
-	return SOCKET_ERROR;
-    }
-
     return getsockopt(s, level, optname, optval, optlen);
 }
 
+#undef TclWinSetSockOpt
 int
 TclWinSetSockOpt(SOCKET s, int level, int optname, const char *optval,
     int optlen)
 {
-    /*
-     * Check that WinSock is initialized; do not call it if not, to prevent
-     * system crashes. This can happen at exit time if the exit handler for
-     * WinSock ran before other exit handlers that want to use sockets.
-     */
-
-    if (!SocketsEnabled()) {
-	return SOCKET_ERROR;
-    }
-
     return setsockopt(s, level, optname, optval, optlen);
 }
 
 char *
 TclpInetNtoa(struct in_addr addr)
 {
-    /*
-     * Check that WinSock is initialized; do not call it if not, to prevent
-     * system crashes. This can happen at exit time if the exit handler for
-     * WinSock ran before other exit handlers that want to use sockets.
-     */
-
-    if (!SocketsEnabled()) {
-        return NULL;
-    }
-
     return inet_ntoa(addr);
 }
 
+#undef TclWinGetServByName
 struct servent *
 TclWinGetServByName(
     const char *name,
     const char *proto)
 {
-    /*
-     * Check that WinSock is initialized; do not call it if not, to prevent
-     * system crashes. This can happen at exit time if the exit handler for
-     * WinSock ran before other exit handlers that want to use sockets.
-     */
-
-    if (!SocketsEnabled()) {
-	return NULL;
-    }
-
     return getservbyname(name, proto);
 }