Merge commit '05fa4c89f20e9769db0e6c0b429cef2590771ace' as 'tcl8.6'

1 files changed, 3167 insertions, 0 deletions

diff --git a/tcl8.6/win/tclWinPipe.c b/tcl8.6/win/tclWinPipe.c
new file mode 100644
index 0000000..382addd
--- /dev/null
+++ b/tcl8.6/win/tclWinPipe.c
@@ -0,0 +1,3167 @@
+/*
+ * tclWinPipe.c --
+ *
+ *	This file implements the Windows-specific exec pipeline functions, the
+ *	"pipe" channel driver, and the "pid" Tcl command.
+ *
+ * Copyright (c) 1996-1997 by Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution of
+ * this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ */
+
+#include "tclWinInt.h"
+
+/*
+ * The following variable is used to tell whether this module has been
+ * initialized.
+ */
+
+static int initialized = 0;
+
+/*
+ * The pipeMutex locks around access to the initialized and procList
+ * variables, and it is used to protect background threads from being
+ * terminated while they are using APIs that hold locks.
+ */
+
+TCL_DECLARE_MUTEX(pipeMutex)
+
+/*
+ * The following defines identify the various types of applications that run
+ * under windows. There is special case code for the various types.
+ */
+
+#define APPL_NONE	0
+#define APPL_DOS	1
+#define APPL_WIN3X	2
+#define APPL_WIN32	3
+
+/*
+ * The following constants and structures are used to encapsulate the state of
+ * various types of files used in a pipeline. This used to have a 1 && 2 that
+ * supported Win32s.
+ */
+
+#define WIN_FILE	3	/* Basic Win32 file. */
+
+/*
+ * This structure encapsulates the common state associated with all file types
+ * used in a pipeline.
+ */
+
+typedef struct {
+    int type;			/* One of the file types defined above. */
+    HANDLE handle;		/* Open file handle. */
+} WinFile;
+
+/*
+ * This list is used to map from pids to process handles.
+ */
+
+typedef struct ProcInfo {
+    HANDLE hProcess;
+    DWORD dwProcessId;
+    struct ProcInfo *nextPtr;
+} ProcInfo;
+
+static ProcInfo *procList;
+
+/*
+ * Bit masks used in the flags field of the PipeInfo structure below.
+ */
+
+#define PIPE_PENDING	(1<<0)	/* Message is pending in the queue. */
+#define PIPE_ASYNC	(1<<1)	/* Channel is non-blocking. */
+
+/*
+ * Bit masks used in the sharedFlags field of the PipeInfo structure below.
+ */
+
+#define PIPE_EOF	(1<<2)	/* Pipe has reached EOF. */
+#define PIPE_EXTRABYTE	(1<<3)	/* The reader thread has consumed one byte. */
+
+/*
+ * TODO: It appears the whole EXTRABYTE machinery is in place to support
+ * outdated Win 95 systems.  If this can be confirmed, much code can be
+ * deleted.
+ */
+
+/*
+ * This structure describes per-instance data for a pipe based channel.
+ */
+
+typedef struct PipeInfo {
+    struct PipeInfo *nextPtr;	/* Pointer to next registered pipe. */
+    Tcl_Channel channel;	/* Pointer to channel structure. */
+    int validMask;		/* OR'ed combination of TCL_READABLE,
+				 * TCL_WRITABLE, or TCL_EXCEPTION: indicates
+				 * which operations are valid on the file. */
+    int watchMask;		/* OR'ed combination of TCL_READABLE,
+				 * TCL_WRITABLE, or TCL_EXCEPTION: indicates
+				 * which events should be reported. */
+    int flags;			/* State flags, see above for a list. */
+    TclFile readFile;		/* Output from pipe. */
+    TclFile writeFile;		/* Input from pipe. */
+    TclFile errorFile;		/* Error output from pipe. */
+    int numPids;		/* Number of processes attached to pipe. */
+    Tcl_Pid *pidPtr;		/* Pids of attached processes. */
+    Tcl_ThreadId threadId;	/* Thread to which events should be reported.
+				 * This value is used by the reader/writer
+				 * threads. */
+    HANDLE writeThread;		/* Handle to writer thread. */
+    HANDLE readThread;		/* Handle to reader thread. */
+    HANDLE writable;		/* Manual-reset event to signal when the
+				 * writer thread has finished waiting for the
+				 * current buffer to be written. */
+    HANDLE readable;		/* Manual-reset event to signal when the
+				 * reader thread has finished waiting for
+				 * input. */
+    HANDLE startWriter;		/* Auto-reset event used by the main thread to
+				 * signal when the writer thread should
+				 * attempt to write to the pipe. */
+    HANDLE stopWriter;		/* Manual-reset event used to alert the reader
+				 * thread to fall-out and exit */
+    HANDLE startReader;		/* Auto-reset event used by the main thread to
+				 * signal when the reader thread should
+				 * attempt to read from the pipe. */
+    HANDLE stopReader;		/* Manual-reset event used to alert the reader
+				 * thread to fall-out and exit */
+    DWORD writeError;		/* An error caused by the last background
+				 * write. Set to 0 if no error has been
+				 * detected. This word is shared with the
+				 * writer thread so access must be
+				 * synchronized with the writable object.
+				 */
+    char *writeBuf;		/* Current background output buffer. Access is
+				 * synchronized with the writable object. */
+    int writeBufLen;		/* Size of write buffer. Access is
+				 * synchronized with the writable object. */
+    int toWrite;		/* Current amount to be written. Access is
+				 * synchronized with the writable object. */
+    int readFlags;		/* Flags that are shared with the reader
+				 * thread. Access is synchronized with the
+				 * readable object.  */
+    char extraByte;		/* Buffer for extra character consumed by
+				 * reader thread. This byte is shared with the
+				 * reader thread so access must be
+				 * synchronized with the readable object. */
+} PipeInfo;
+
+typedef struct {
+    /*
+     * The following pointer refers to the head of the list of pipes that are
+     * being watched for file events.
+     */
+
+    PipeInfo *firstPipePtr;
+} ThreadSpecificData;
+
+static Tcl_ThreadDataKey dataKey;
+
+/*
+ * The following structure is what is added to the Tcl event queue when pipe
+ * events are generated.
+ */
+
+typedef struct {
+    Tcl_Event header;		/* Information that is standard for all
+				 * events. */
+    PipeInfo *infoPtr;		/* Pointer to pipe info structure. Note that
+				 * we still have to verify that the pipe
+				 * exists before dereferencing this
+				 * pointer. */
+} PipeEvent;
+
+/*
+ * Declarations for functions used only in this file.
+ */
+
+static int		ApplicationType(Tcl_Interp *interp,
+			    const char *fileName, char *fullName);
+static void		BuildCommandLine(const char *executable, int argc,
+			    const char **argv, Tcl_DString *linePtr);
+static BOOL		HasConsole(void);
+static int		PipeBlockModeProc(ClientData instanceData, int mode);
+static void		PipeCheckProc(ClientData clientData, int flags);
+static int		PipeClose2Proc(ClientData instanceData,
+			    Tcl_Interp *interp, int flags);
+static int		PipeEventProc(Tcl_Event *evPtr, int flags);
+static int		PipeGetHandleProc(ClientData instanceData,
+			    int direction, ClientData *handlePtr);
+static void		PipeInit(void);
+static int		PipeInputProc(ClientData instanceData, char *buf,
+			    int toRead, int *errorCode);
+static int		PipeOutputProc(ClientData instanceData,
+			    const char *buf, int toWrite, int *errorCode);
+static DWORD WINAPI	PipeReaderThread(LPVOID arg);
+static void		PipeSetupProc(ClientData clientData, int flags);
+static void		PipeWatchProc(ClientData instanceData, int mask);
+static DWORD WINAPI	PipeWriterThread(LPVOID arg);
+static int		TempFileName(TCHAR name[MAX_PATH]);
+static int		WaitForRead(PipeInfo *infoPtr, int blocking);
+static void		PipeThreadActionProc(ClientData instanceData,
+			    int action);
+
+/*
+ * This structure describes the channel type structure for command pipe based
+ * I/O.
+ */
+
+static const Tcl_ChannelType pipeChannelType = {
+    "pipe",			/* Type name. */
+    TCL_CHANNEL_VERSION_5,	/* v5 channel */
+    TCL_CLOSE2PROC,		/* Close proc. */
+    PipeInputProc,		/* Input proc. */
+    PipeOutputProc,		/* Output proc. */
+    NULL,			/* Seek proc. */
+    NULL,			/* Set option proc. */
+    NULL,			/* Get option proc. */
+    PipeWatchProc,		/* Set up notifier to watch the channel. */
+    PipeGetHandleProc,		/* Get an OS handle from channel. */
+    PipeClose2Proc,		/* close2proc */
+    PipeBlockModeProc,		/* Set blocking or non-blocking mode.*/
+    NULL,			/* flush proc. */
+    NULL,			/* handler proc. */
+    NULL,			/* wide seek proc */
+    PipeThreadActionProc,	/* thread action proc */
+    NULL                       /* truncate */
+};
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeInit --
+ *
+ *	This function initializes the static variables for this file.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Creates a new event source.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+PipeInit(void)
+{
+    ThreadSpecificData *tsdPtr;
+
+    /*
+     * Check the initialized flag first, then check again in the mutex. This
+     * is a speed enhancement.
+     */
+
+    if (!initialized) {
+	Tcl_MutexLock(&pipeMutex);
+	if (!initialized) {
+	    initialized = 1;
+	    procList = NULL;
+	}
+	Tcl_MutexUnlock(&pipeMutex);
+    }
+
+    tsdPtr = (ThreadSpecificData *)TclThreadDataKeyGet(&dataKey);
+    if (tsdPtr == NULL) {
+	tsdPtr = TCL_TSD_INIT(&dataKey);
+	tsdPtr->firstPipePtr = NULL;
+	Tcl_CreateEventSource(PipeSetupProc, PipeCheckProc, NULL);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpFinalizePipes --
+ *
+ *	This function is called from Tcl_FinalizeThread to finalize the
+ *	platform specific pipe subsystem.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Removes the pipe event source.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclpFinalizePipes(void)
+{
+    ThreadSpecificData *tsdPtr;
+
+    tsdPtr = (ThreadSpecificData *)TclThreadDataKeyGet(&dataKey);
+    if (tsdPtr != NULL) {
+	Tcl_DeleteEventSource(PipeSetupProc, PipeCheckProc, NULL);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeSetupProc --
+ *
+ *	This function is invoked before Tcl_DoOneEvent blocks waiting for an
+ *	event.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Adjusts the block time if needed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+PipeSetupProc(
+    ClientData data,		/* Not used. */
+    int flags)			/* Event flags as passed to Tcl_DoOneEvent. */
+{
+    PipeInfo *infoPtr;
+    Tcl_Time blockTime = { 0, 0 };
+    int block = 1;
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    if (!(flags & TCL_FILE_EVENTS)) {
+	return;
+    }
+
+    /*
+     * Look to see if any events are already pending.  If they are, poll.
+     */
+
+    for (infoPtr = tsdPtr->firstPipePtr; infoPtr != NULL;
+	    infoPtr = infoPtr->nextPtr) {
+	if (infoPtr->watchMask & TCL_WRITABLE) {
+	    if (WaitForSingleObject(infoPtr->writable, 0) != WAIT_TIMEOUT) {
+		block = 0;
+	    }
+	}
+	if (infoPtr->watchMask & TCL_READABLE) {
+	    if (WaitForRead(infoPtr, 0) >= 0) {
+		block = 0;
+	    }
+	}
+    }
+    if (!block) {
+	Tcl_SetMaxBlockTime(&blockTime);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeCheckProc --
+ *
+ *	This function is called by Tcl_DoOneEvent to check the pipe event
+ *	source for events.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	May queue an event.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+PipeCheckProc(
+    ClientData data,		/* Not used. */
+    int flags)			/* Event flags as passed to Tcl_DoOneEvent. */
+{
+    PipeInfo *infoPtr;
+    PipeEvent *evPtr;
+    int needEvent;
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    if (!(flags & TCL_FILE_EVENTS)) {
+	return;
+    }
+
+    /*
+     * Queue events for any ready pipes that don't already have events queued.
+     */
+
+    for (infoPtr = tsdPtr->firstPipePtr; infoPtr != NULL;
+	    infoPtr = infoPtr->nextPtr) {
+	if (infoPtr->flags & PIPE_PENDING) {
+	    continue;
+	}
+
+	/*
+	 * Queue an event if the pipe is signaled for reading or writing.
+	 */
+
+	needEvent = 0;
+	if ((infoPtr->watchMask & TCL_WRITABLE) &&
+		(WaitForSingleObject(infoPtr->writable, 0) != WAIT_TIMEOUT)) {
+	    needEvent = 1;
+	}
+
+	if ((infoPtr->watchMask & TCL_READABLE) &&
+		(WaitForRead(infoPtr, 0) >= 0)) {
+	    needEvent = 1;
+	}
+
+	if (needEvent) {
+	    infoPtr->flags |= PIPE_PENDING;
+	    evPtr = ckalloc(sizeof(PipeEvent));
+	    evPtr->header.proc = PipeEventProc;
+	    evPtr->infoPtr = infoPtr;
+	    Tcl_QueueEvent((Tcl_Event *) evPtr, TCL_QUEUE_TAIL);
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclWinMakeFile --
+ *
+ *	This function constructs a new TclFile from a given data and type
+ *	value.
+ *
+ * Results:
+ *	Returns a newly allocated WinFile as a TclFile.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+TclFile
+TclWinMakeFile(
+    HANDLE handle)		/* Type-specific data. */
+{
+    WinFile *filePtr;
+
+    filePtr = ckalloc(sizeof(WinFile));
+    filePtr->type = WIN_FILE;
+    filePtr->handle = handle;
+
+    return (TclFile)filePtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TempFileName --
+ *
+ *	Gets a temporary file name and deals with the fact that the temporary
+ *	file path provided by Windows may not actually exist if the TMP or
+ *	TEMP environment variables refer to a non-existent directory.
+ *
+ * Results:
+ *	0 if error, non-zero otherwise. If non-zero is returned, the name
+ *	buffer will be filled with a name that can be used to construct a
+ *	temporary file.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+TempFileName(
+    TCHAR name[MAX_PATH])	/* Buffer in which name for temporary file
+				 * gets stored. */
+{
+    const TCHAR *prefix = TEXT("TCL");
+    if (GetTempPath(MAX_PATH, name) != 0) {
+	if (GetTempFileName(name, prefix, 0, name) != 0) {
+	    return 1;
+	}
+    }
+    name[0] = '.';
+    name[1] = '\0';
+    return GetTempFileName(name, prefix, 0, name);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpMakeFile --
+ *
+ *	Make a TclFile from a channel.
+ *
+ * Results:
+ *	Returns a new TclFile or NULL on failure.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+TclFile
+TclpMakeFile(
+    Tcl_Channel channel,	/* Channel to get file from. */
+    int direction)		/* Either TCL_READABLE or TCL_WRITABLE. */
+{
+    HANDLE handle;
+
+    if (Tcl_GetChannelHandle(channel, direction,
+	    (ClientData *) &handle) == TCL_OK) {
+	return TclWinMakeFile(handle);
+    } else {
+	return (TclFile) NULL;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpOpenFile --
+ *
+ *	This function opens files for use in a pipeline.
+ *
+ * Results:
+ *	Returns a newly allocated TclFile structure containing the file
+ *	handle.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+TclFile
+TclpOpenFile(
+    const char *path,		/* The name of the file to open. */
+    int mode)			/* In what mode to open the file? */
+{
+    HANDLE handle;
+    DWORD accessMode, createMode, shareMode, flags;
+    Tcl_DString ds;
+    const TCHAR *nativePath;
+
+    /*
+     * Map the access bits to the NT access mode.
+     */
+
+    switch (mode & (O_RDONLY | O_WRONLY | O_RDWR)) {
+    case O_RDONLY:
+	accessMode = GENERIC_READ;
+	break;
+    case O_WRONLY:
+	accessMode = GENERIC_WRITE;
+	break;
+    case O_RDWR:
+	accessMode = (GENERIC_READ | GENERIC_WRITE);
+	break;
+    default:
+	TclWinConvertError(ERROR_INVALID_FUNCTION);
+	return NULL;
+    }
+
+    /*
+     * Map the creation flags to the NT create mode.
+     */
+
+    switch (mode & (O_CREAT | O_EXCL | O_TRUNC)) {
+    case (O_CREAT | O_EXCL):
+    case (O_CREAT | O_EXCL | O_TRUNC):
+	createMode = CREATE_NEW;
+	break;
+    case (O_CREAT | O_TRUNC):
+	createMode = CREATE_ALWAYS;
+	break;
+    case O_CREAT:
+	createMode = OPEN_ALWAYS;
+	break;
+    case O_TRUNC:
+    case (O_TRUNC | O_EXCL):
+	createMode = TRUNCATE_EXISTING;
+	break;
+    default:
+	createMode = OPEN_EXISTING;
+	break;
+    }
+
+    nativePath = Tcl_WinUtfToTChar(path, -1, &ds);
+
+    /*
+     * If the file is not being created, use the existing file attributes.
+     */
+
+    flags = 0;
+    if (!(mode & O_CREAT)) {
+	flags = GetFileAttributes(nativePath);
+	if (flags == 0xFFFFFFFF) {
+	    flags = 0;
+	}
+    }
+
+    /*
+     * Set up the file sharing mode.  We want to allow simultaneous access.
+     */
+
+    shareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;
+
+    /*
+     * Now we get to create the file.
+     */
+
+    handle = CreateFile(nativePath, accessMode, shareMode,
+	    NULL, createMode, flags, NULL);
+    Tcl_DStringFree(&ds);
+
+    if (handle == INVALID_HANDLE_VALUE) {
+	DWORD err;
+
+	err = GetLastError();
+	if ((err & 0xffffL) == ERROR_OPEN_FAILED) {
+	    err = (mode & O_CREAT) ? ERROR_FILE_EXISTS : ERROR_FILE_NOT_FOUND;
+	}
+	TclWinConvertError(err);
+	return NULL;
+    }
+
+    /*
+     * Seek to the end of file if we are writing.
+     */
+
+    if (mode & (O_WRONLY|O_APPEND)) {
+	SetFilePointer(handle, 0, NULL, FILE_END);
+    }
+
+    return TclWinMakeFile(handle);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpCreateTempFile --
+ *
+ *	This function opens a unique file with the property that it will be
+ *	deleted when its file handle is closed. The temporary file is created
+ *	in the system temporary directory.
+ *
+ * Results:
+ *	Returns a valid TclFile, or NULL on failure.
+ *
+ * Side effects:
+ *	Creates a new temporary file.
+ *
+ *----------------------------------------------------------------------
+ */
+
+TclFile
+TclpCreateTempFile(
+    const char *contents)	/* String to write into temp file, or NULL. */
+{
+    TCHAR name[MAX_PATH];
+    const char *native;
+    Tcl_DString dstring;
+    HANDLE handle;
+
+    if (TempFileName(name) == 0) {
+	return NULL;
+    }
+
+    handle = CreateFile(name,
+	    GENERIC_READ | GENERIC_WRITE, 0, NULL, CREATE_ALWAYS,
+	    FILE_ATTRIBUTE_TEMPORARY|FILE_FLAG_DELETE_ON_CLOSE, NULL);
+    if (handle == INVALID_HANDLE_VALUE) {
+	goto error;
+    }
+
+    /*
+     * Write the file out, doing line translations on the way.
+     */
+
+    if (contents != NULL) {
+	DWORD result, length;
+	const char *p;
+	int toCopy;
+
+	/*
+	 * Convert the contents from UTF to native encoding
+	 */
+
+	native = Tcl_UtfToExternalDString(NULL, contents, -1, &dstring);
+
+	toCopy = Tcl_DStringLength(&dstring);
+	for (p = native; toCopy > 0; p++, toCopy--) {
+	    if (*p == '\n') {
+		length = p - native;
+		if (length > 0) {
+		    if (!WriteFile(handle, native, length, &result, NULL)) {
+			goto error;
+		    }
+		}
+		if (!WriteFile(handle, "\r\n", 2, &result, NULL)) {
+		    goto error;
+		}
+		native = p+1;
+	    }
+	}
+	length = p - native;
+	if (length > 0) {
+	    if (!WriteFile(handle, native, length, &result, NULL)) {
+		goto error;
+	    }
+	}
+	Tcl_DStringFree(&dstring);
+	if (SetFilePointer(handle, 0, NULL, FILE_BEGIN) == 0xFFFFFFFF) {
+	    goto error;
+	}
+    }
+
+    return TclWinMakeFile(handle);
+
+  error:
+    /*
+     * Free the native representation of the contents if necessary.
+     */
+
+    if (contents != NULL) {
+	Tcl_DStringFree(&dstring);
+    }
+
+    TclWinConvertError(GetLastError());
+    CloseHandle(handle);
+    DeleteFile(name);
+    return NULL;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpTempFileName --
+ *
+ *	This function returns a unique filename.
+ *
+ * Results:
+ *	Returns a valid Tcl_Obj* with refCount 0, or NULL on failure.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Obj *
+TclpTempFileName(void)
+{
+    TCHAR fileName[MAX_PATH];
+
+    if (TempFileName(fileName) == 0) {
+	return NULL;
+    }
+
+    return TclpNativeToNormalized(fileName);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpCreatePipe --
+ *
+ *	Creates an anonymous pipe.
+ *
+ * Results:
+ *	Returns 1 on success, 0 on failure.
+ *
+ * Side effects:
+ *	Creates a pipe.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclpCreatePipe(
+    TclFile *readPipe,		/* Location to store file handle for read side
+				 * of pipe. */
+    TclFile *writePipe)		/* Location to store file handle for write
+				 * side of pipe. */
+{
+    HANDLE readHandle, writeHandle;
+
+    if (CreatePipe(&readHandle, &writeHandle, NULL, 0) != 0) {
+	*readPipe = TclWinMakeFile(readHandle);
+	*writePipe = TclWinMakeFile(writeHandle);
+	return 1;
+    }
+
+    TclWinConvertError(GetLastError());
+    return 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpCloseFile --
+ *
+ *	Closes a pipeline file handle. These handles are created by
+ *	TclpOpenFile, TclpCreatePipe, or TclpMakeFile.
+ *
+ * Results:
+ *	0 on success, -1 on failure.
+ *
+ * Side effects:
+ *	The file is closed and deallocated.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclpCloseFile(
+    TclFile file)		/* The file to close. */
+{
+    WinFile *filePtr = (WinFile *) file;
+
+    switch (filePtr->type) {
+    case WIN_FILE:
+	/*
+	 * Don't close the Win32 handle if the handle is a standard channel
+	 * during the thread exit process. Otherwise, one thread may kill the
+	 * stdio of another.
+	 */
+
+	if (!TclInThreadExit()
+		|| ((GetStdHandle(STD_INPUT_HANDLE) != filePtr->handle)
+		    && (GetStdHandle(STD_OUTPUT_HANDLE) != filePtr->handle)
+		    && (GetStdHandle(STD_ERROR_HANDLE) != filePtr->handle))) {
+	    if (filePtr->handle != NULL &&
+		    CloseHandle(filePtr->handle) == FALSE) {
+		TclWinConvertError(GetLastError());
+		ckfree(filePtr);
+		return -1;
+	    }
+	}
+	break;
+
+    default:
+	Tcl_Panic("TclpCloseFile: unexpected file type");
+    }
+
+    ckfree(filePtr);
+    return 0;
+}
+
+/*
+ *--------------------------------------------------------------------------
+ *
+ * TclpGetPid --
+ *
+ *	Given a HANDLE to a child process, return the process id for that
+ *	child process.
+ *
+ * Results:
+ *	Returns the process id for the child process. If the pid was not known
+ *	by Tcl, either because the pid was not created by Tcl or the child
+ *	process has already been reaped, -1 is returned.
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------------------
+ */
+
+int
+TclpGetPid(
+    Tcl_Pid pid)		/* The HANDLE of the child process. */
+{
+    ProcInfo *infoPtr;
+
+    PipeInit();
+
+    Tcl_MutexLock(&pipeMutex);
+    for (infoPtr = procList; infoPtr != NULL; infoPtr = infoPtr->nextPtr) {
+	if (infoPtr->hProcess == (HANDLE) pid) {
+	    Tcl_MutexUnlock(&pipeMutex);
+	    return infoPtr->dwProcessId;
+	}
+    }
+    Tcl_MutexUnlock(&pipeMutex);
+    return (unsigned long) -1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpCreateProcess --
+ *
+ *	Create a child process that has the specified files as its standard
+ *	input, output, and error. The child process runs asynchronously under
+ *	Windows NT and Windows 9x, and runs with the same environment
+ *	variables as the creating process.
+ *
+ *	The complete Windows search path is searched to find the specified
+ *	executable. If an executable by the given name is not found,
+ *	automatically tries appending standard extensions to the
+ *	executable name.
+ *
+ * Results:
+ *	The return value is TCL_ERROR and an error message is left in the
+ *	interp's result if there was a problem creating the child process.
+ *	Otherwise, the return value is TCL_OK and *pidPtr is filled with the
+ *	process id of the child process.
+ *
+ * Side effects:
+ *	A process is created.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclpCreateProcess(
+    Tcl_Interp *interp,		/* Interpreter in which to leave errors that
+				 * occurred when creating the child process.
+				 * Error messages from the child process
+				 * itself are sent to errorFile. */
+    int argc,			/* Number of arguments in following array. */
+    const char **argv,		/* Array of argument strings. argv[0] contains
+				 * the name of the executable converted to
+				 * native format (using the
+				 * Tcl_TranslateFileName call). Additional
+				 * arguments have not been converted. */
+    TclFile inputFile,		/* If non-NULL, gives the file to use as input
+				 * for the child process. If inputFile file is
+				 * not readable or is NULL, the child will
+				 * receive no standard input. */
+    TclFile outputFile,		/* If non-NULL, gives the file that receives
+				 * output from the child process. If
+				 * outputFile file is not writeable or is
+				 * NULL, output from the child will be
+				 * discarded. */
+    TclFile errorFile,		/* If non-NULL, gives the file that receives
+				 * errors from the child process. If errorFile
+				 * file is not writeable or is NULL, errors
+				 * from the child will be discarded. errorFile
+				 * may be the same as outputFile. */
+    Tcl_Pid *pidPtr)		/* If this function is successful, pidPtr is
+				 * filled with the process id of the child
+				 * process. */
+{
+    int result, applType, createFlags;
+    Tcl_DString cmdLine;	/* Complete command line (TCHAR). */
+    STARTUPINFO startInfo;
+    PROCESS_INFORMATION procInfo;
+    SECURITY_ATTRIBUTES secAtts;
+    HANDLE hProcess, h, inputHandle, outputHandle, errorHandle;
+    char execPath[MAX_PATH * TCL_UTF_MAX];
+    WinFile *filePtr;
+
+    PipeInit();
+
+    applType = ApplicationType(interp, argv[0], execPath);
+    if (applType == APPL_NONE) {
+	return TCL_ERROR;
+    }
+
+    result = TCL_ERROR;
+    Tcl_DStringInit(&cmdLine);
+    hProcess = GetCurrentProcess();
+
+    /*
+     * STARTF_USESTDHANDLES must be used to pass handles to child process.
+     * Using SetStdHandle() and/or dup2() only works when a console mode
+     * parent process is spawning an attached console mode child process.
+     */
+
+    ZeroMemory(&startInfo, sizeof(startInfo));
+    startInfo.cb = sizeof(startInfo);
+    startInfo.dwFlags	= STARTF_USESTDHANDLES;
+    startInfo.hStdInput	= INVALID_HANDLE_VALUE;
+    startInfo.hStdOutput= INVALID_HANDLE_VALUE;
+    startInfo.hStdError = INVALID_HANDLE_VALUE;
+
+    secAtts.nLength = sizeof(SECURITY_ATTRIBUTES);
+    secAtts.lpSecurityDescriptor = NULL;
+    secAtts.bInheritHandle = TRUE;
+
+    /*
+     * We have to check the type of each file, since we cannot duplicate some
+     * file types.
+     */
+
+    inputHandle = INVALID_HANDLE_VALUE;
+    if (inputFile != NULL) {
+	filePtr = (WinFile *)inputFile;
+	if (filePtr->type == WIN_FILE) {
+	    inputHandle = filePtr->handle;
+	}
+    }
+    outputHandle = INVALID_HANDLE_VALUE;
+    if (outputFile != NULL) {
+	filePtr = (WinFile *)outputFile;
+	if (filePtr->type == WIN_FILE) {
+	    outputHandle = filePtr->handle;
+	}
+    }
+    errorHandle = INVALID_HANDLE_VALUE;
+    if (errorFile != NULL) {
+	filePtr = (WinFile *)errorFile;
+	if (filePtr->type == WIN_FILE) {
+	    errorHandle = filePtr->handle;
+	}
+    }
+
+    /*
+     * Duplicate all the handles which will be passed off as stdin, stdout and
+     * stderr of the child process. The duplicate handles are set to be
+     * inheritable, so the child process can use them.
+     */
+
+    if (inputHandle == INVALID_HANDLE_VALUE) {
+	/*
+	 * If handle was not set, stdin should return immediate EOF. Under
+	 * Windows95, some applications (both 16 and 32 bit!) cannot read from
+	 * the NUL device; they read from console instead. When running tk,
+	 * this is fatal because the child process would hang forever waiting
+	 * for EOF from the unmapped console window used by the helper
+	 * application.
+	 *
+	 * Fortunately, the helper application detects a closed pipe as an
+	 * immediate EOF and can pass that information to the child process.
+	 */
+
+	if (CreatePipe(&startInfo.hStdInput, &h, &secAtts, 0) != FALSE) {
+	    CloseHandle(h);
+	}
+    } else {
+	DuplicateHandle(hProcess, inputHandle, hProcess, &startInfo.hStdInput,
+		0, TRUE, DUPLICATE_SAME_ACCESS);
+    }
+    if (startInfo.hStdInput == INVALID_HANDLE_VALUE) {
+	TclWinConvertError(GetLastError());
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"couldn't duplicate input handle: %s",
+		Tcl_PosixError(interp)));
+	goto end;
+    }
+
+    if (outputHandle == INVALID_HANDLE_VALUE) {
+	/*
+	 * If handle was not set, output should be sent to an infinitely deep
+	 * sink. Under Windows 95, some 16 bit applications cannot have stdout
+	 * redirected to NUL; they send their output to the console instead.
+	 * Some applications, like "more" or "dir /p", when outputting
+	 * multiple pages to the console, also then try and read from the
+	 * console to go the next page. When running tk, this is fatal because
+	 * the child process would hang forever waiting for input from the
+	 * unmapped console window used by the helper application.
+	 *
+	 * Fortunately, the helper application will detect a closed pipe as a
+	 * sink.
+	 */
+
+	startInfo.hStdOutput = CreateFile(TEXT("NUL:"), GENERIC_WRITE, 0,
+		&secAtts, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+    } else {
+	DuplicateHandle(hProcess, outputHandle, hProcess,
+		&startInfo.hStdOutput, 0, TRUE, DUPLICATE_SAME_ACCESS);
+    }
+    if (startInfo.hStdOutput == INVALID_HANDLE_VALUE) {
+	TclWinConvertError(GetLastError());
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"couldn't duplicate output handle: %s",
+		Tcl_PosixError(interp)));
+	goto end;
+    }
+
+    if (errorHandle == INVALID_HANDLE_VALUE) {
+	/*
+	 * If handle was not set, errors should be sent to an infinitely deep
+	 * sink.
+	 */
+
+	startInfo.hStdError = CreateFile(TEXT("NUL:"), GENERIC_WRITE, 0,
+		&secAtts, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+    } else {
+	DuplicateHandle(hProcess, errorHandle, hProcess, &startInfo.hStdError,
+		0, TRUE, DUPLICATE_SAME_ACCESS);
+    }
+    if (startInfo.hStdError == INVALID_HANDLE_VALUE) {
+	TclWinConvertError(GetLastError());
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"couldn't duplicate error handle: %s",
+		Tcl_PosixError(interp)));
+	goto end;
+    }
+
+    /*
+     * If we do not have a console window, then we must run DOS and WIN32
+     * console mode applications as detached processes. This tells the loader
+     * that the child application should not inherit the console, and that it
+     * should not create a new console window for the child application. The
+     * child application should get its stdio from the redirection handles
+     * provided by this application, and run in the background.
+     *
+     * If we are starting a GUI process, they don't automatically get a
+     * console, so it doesn't matter if they are started as foreground or
+     * detached processes. The GUI window will still pop up to the foreground.
+     */
+
+    if (TclWinGetPlatformId() == VER_PLATFORM_WIN32_NT) {
+	if (HasConsole()) {
+	    createFlags = 0;
+	} else if (applType == APPL_DOS) {
+	    /*
+	     * Under NT, 16-bit DOS applications will not run unless they can
+	     * be attached to a console. If we are running without a console,
+	     * run the 16-bit program as an normal process inside of a hidden
+	     * console application, and then run that hidden console as a
+	     * detached process.
+	     */
+
+	    startInfo.wShowWindow = SW_HIDE;
+	    startInfo.dwFlags |= STARTF_USESHOWWINDOW;
+	    createFlags = CREATE_NEW_CONSOLE;
+	    TclDStringAppendLiteral(&cmdLine, "cmd.exe /c");
+	} else {
+	    createFlags = DETACHED_PROCESS;
+	}
+    } else {
+	if (HasConsole()) {
+	    createFlags = 0;
+	} else {
+	    createFlags = DETACHED_PROCESS;
+	}
+
+	if (applType == APPL_DOS) {
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "DOS application process not supported on this platform",
+		    -1));
+	    Tcl_SetErrorCode(interp, "TCL", "OPERATION", "EXEC", "DOS_APP",
+		    NULL);
+	    goto end;
+	}
+    }
+
+    /*
+     * cmdLine gets the full command line used to invoke the executable,
+     * including the name of the executable itself. The command line arguments
+     * in argv[] are stored in cmdLine separated by spaces. Special characters
+     * in individual arguments from argv[] must be quoted when being stored in
+     * cmdLine.
+     *
+     * When calling any application, bear in mind that arguments that specify
+     * a path name are not converted. If an argument contains forward slashes
+     * as path separators, it may or may not be recognized as a path name,
+     * depending on the program. In general, most applications accept forward
+     * slashes only as option delimiters and backslashes only as paths.
+     *
+     * Additionally, when calling a 16-bit dos or windows application, all
+     * path names must use the short, cryptic, path format (e.g., using
+     * ab~1.def instead of "a b.default").
+     */
+
+    BuildCommandLine(execPath, argc, argv, &cmdLine);
+
+    if (CreateProcess(NULL, (TCHAR *) Tcl_DStringValue(&cmdLine),
+	    NULL, NULL, TRUE, (DWORD) createFlags, NULL, NULL, &startInfo,
+	    &procInfo) == 0) {
+	TclWinConvertError(GetLastError());
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf("couldn't execute \"%s\": %s",
+		argv[0], Tcl_PosixError(interp)));
+	goto end;
+    }
+
+    /*
+     * This wait is used to force the OS to give some time to the DOS process.
+     */
+
+    if (applType == APPL_DOS) {
+	WaitForSingleObject(procInfo.hProcess, 50);
+    }
+
+    /*
+     * "When an application spawns a process repeatedly, a new thread instance
+     * will be created for each process but the previous instances may not be
+     * cleaned up. This results in a significant virtual memory loss each time
+     * the process is spawned. If there is a WaitForInputIdle() call between
+     * CreateProcess() and CloseHandle(), the problem does not occur." PSS ID
+     * Number: Q124121
+     */
+
+    WaitForInputIdle(procInfo.hProcess, 5000);
+    CloseHandle(procInfo.hThread);
+
+    *pidPtr = (Tcl_Pid) procInfo.hProcess;
+    if (*pidPtr != 0) {
+	TclWinAddProcess(procInfo.hProcess, procInfo.dwProcessId);
+    }
+    result = TCL_OK;
+
+  end:
+    Tcl_DStringFree(&cmdLine);
+    if (startInfo.hStdInput != INVALID_HANDLE_VALUE) {
+	CloseHandle(startInfo.hStdInput);
+    }
+    if (startInfo.hStdOutput != INVALID_HANDLE_VALUE) {
+	CloseHandle(startInfo.hStdOutput);
+    }
+    if (startInfo.hStdError != INVALID_HANDLE_VALUE) {
+	CloseHandle(startInfo.hStdError);
+    }
+    return result;
+}
+
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * HasConsole --
+ *
+ *	Determines whether the current application is attached to a console.
+ *
+ * Results:
+ *	Returns TRUE if this application has a console, else FALSE.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static BOOL
+HasConsole(void)
+{
+    HANDLE handle;
+
+    handle = CreateFileA("CONOUT$", GENERIC_WRITE, FILE_SHARE_WRITE,
+	    NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+
+    if (handle != INVALID_HANDLE_VALUE) {
+	CloseHandle(handle);
+	return TRUE;
+    } else {
+	return FALSE;
+    }
+}
+
+/*
+ *--------------------------------------------------------------------
+ *
+ * ApplicationType --
+ *
+ *	Search for the specified program and identify if it refers to a DOS,
+ *	Windows 3.X, or Win32 program.	Used to determine how to invoke a
+ *	program, or if it can even be invoked.
+ *
+ *	It is possible to almost positively identify DOS and Windows
+ *	applications that contain the appropriate magic numbers. However, DOS
+ *	.com files do not seem to contain a magic number; if the program name
+ *	ends with .com and could not be identified as a Windows .com file, it
+ *	will be assumed to be a DOS application, even if it was just random
+ *	data. If the program name does not end with .com, no such assumption
+ *	is made.
+ *
+ *	The Win32 function GetBinaryType incorrectly identifies any junk file
+ *	that ends with .exe as a dos executable and some executables that
+ *	don't end with .exe as not executable. Plus it doesn't exist under
+ *	win95, so I won't feel bad about reimplementing functionality.
+ *
+ * Results:
+ *	The return value is one of APPL_DOS, APPL_WIN3X, or APPL_WIN32 if the
+ *	filename referred to the corresponding application type. If the file
+ *	name could not be found or did not refer to any known application
+ *	type, APPL_NONE is returned and an error message is left in interp.
+ *	.bat files are identified as APPL_DOS.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+ApplicationType(
+    Tcl_Interp *interp,		/* Interp, for error message. */
+    const char *originalName,	/* Name of the application to find. */
+    char fullName[])		/* Filled with complete path to
+				 * application. */
+{
+    int applType, i, nameLen, found;
+    HANDLE hFile;
+    TCHAR *rest;
+    char *ext;
+    char buf[2];
+    DWORD attr, read;
+    IMAGE_DOS_HEADER header;
+    Tcl_DString nameBuf, ds;
+    const TCHAR *nativeName;
+    TCHAR nativeFullPath[MAX_PATH];
+    static const char extensions[][5] = {"", ".com", ".exe", ".bat", ".cmd"};
+
+    /*
+     * Look for the program as an external program. First try the name as it
+     * is, then try adding .com, .exe, and .bat, in that order, to the name,
+     * looking for an executable.
+     *
+     * Using the raw SearchPath() function doesn't do quite what is necessary.
+     * If the name of the executable already contains a '.' character, it will
+     * not try appending the specified extension when searching (in other
+     * words, SearchPath will not find the program "a.b.exe" if the arguments
+     * specified "a.b" and ".exe"). So, first look for the file as it is
+     * named. Then manually append the extensions, looking for a match.
+     */
+
+    applType = APPL_NONE;
+    Tcl_DStringInit(&nameBuf);
+    Tcl_DStringAppend(&nameBuf, originalName, -1);
+    nameLen = Tcl_DStringLength(&nameBuf);
+
+    for (i = 0; i < (int) (sizeof(extensions) / sizeof(extensions[0])); i++) {
+	Tcl_DStringSetLength(&nameBuf, nameLen);
+	Tcl_DStringAppend(&nameBuf, extensions[i], -1);
+	nativeName = Tcl_WinUtfToTChar(Tcl_DStringValue(&nameBuf),
+		Tcl_DStringLength(&nameBuf), &ds);
+	found = SearchPath(NULL, nativeName, NULL, MAX_PATH,
+		nativeFullPath, &rest);
+	Tcl_DStringFree(&ds);
+	if (found == 0) {
+	    continue;
+	}
+
+	/*
+	 * Ignore matches on directories or data files, return if identified a
+	 * known type.
+	 */
+
+	attr = GetFileAttributes(nativeFullPath);
+	if ((attr == 0xffffffff) || (attr & FILE_ATTRIBUTE_DIRECTORY)) {
+	    continue;
+	}
+	strcpy(fullName, Tcl_WinTCharToUtf(nativeFullPath, -1, &ds));
+	Tcl_DStringFree(&ds);
+
+	ext = strrchr(fullName, '.');
+	if ((ext != NULL) && 
+            (strcasecmp(ext, ".cmd") == 0 || strcasecmp(ext, ".bat") == 0)) {
+	    applType = APPL_DOS;
+	    break;
+	}
+
+	hFile = CreateFile(nativeFullPath,
+		GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING,
+		FILE_ATTRIBUTE_NORMAL, NULL);
+	if (hFile == INVALID_HANDLE_VALUE) {
+	    continue;
+	}
+
+	header.e_magic = 0;
+	ReadFile(hFile, (void *) &header, sizeof(header), &read, NULL);
+	if (header.e_magic != IMAGE_DOS_SIGNATURE) {
+	    /*
+	     * Doesn't have the magic number for relocatable executables. If
+	     * filename ends with .com, assume it's a DOS application anyhow.
+	     * Note that we didn't make this assumption at first, because some
+	     * supposed .com files are really 32-bit executables with all the
+	     * magic numbers and everything.
+	     */
+
+	    CloseHandle(hFile);
+	    if ((ext != NULL) && (strcasecmp(ext, ".com") == 0)) {
+		applType = APPL_DOS;
+		break;
+	    }
+	    continue;
+	}
+	if (header.e_lfarlc != sizeof(header)) {
+	    /*
+	     * All Windows 3.X and Win32 and some DOS programs have this value
+	     * set here. If it doesn't, assume that since it already had the
+	     * other magic number it was a DOS application.
+	     */
+
+	    CloseHandle(hFile);
+	    applType = APPL_DOS;
+	    break;
+	}
+
+	/*
+	 * The DWORD at header.e_lfanew points to yet another magic number.
+	 */
+
+	buf[0] = '\0';
+	SetFilePointer(hFile, header.e_lfanew, NULL, FILE_BEGIN);
+	ReadFile(hFile, (void *) buf, 2, &read, NULL);
+	CloseHandle(hFile);
+
+	if ((buf[0] == 'N') && (buf[1] == 'E')) {
+	    applType = APPL_WIN3X;
+	} else if ((buf[0] == 'P') && (buf[1] == 'E')) {
+	    applType = APPL_WIN32;
+	} else {
+	    /*
+	     * Strictly speaking, there should be a test that there is an 'L'
+	     * and 'E' at buf[0..1], to identify the type as DOS, but of
+	     * course we ran into a DOS executable that _doesn't_ have the
+	     * magic number - specifically, one compiled using the Lahey
+	     * Fortran90 compiler.
+	     */
+
+	    applType = APPL_DOS;
+	}
+	break;
+    }
+    Tcl_DStringFree(&nameBuf);
+
+    if (applType == APPL_NONE) {
+	TclWinConvertError(GetLastError());
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf("couldn't execute \"%s\": %s",
+		originalName, Tcl_PosixError(interp)));
+	return APPL_NONE;
+    }
+
+    if ((applType == APPL_DOS) || (applType == APPL_WIN3X)) {
+	/*
+	 * Replace long path name of executable with short path name for
+	 * 16-bit applications. Otherwise the application may not be able to
+	 * correctly parse its own command line to separate off the
+	 * application name from the arguments.
+	 */
+
+	GetShortPathName(nativeFullPath, nativeFullPath, MAX_PATH);
+	strcpy(fullName, Tcl_WinTCharToUtf(nativeFullPath, -1, &ds));
+	Tcl_DStringFree(&ds);
+    }
+    return applType;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * BuildCommandLine --
+ *
+ *	The command line arguments are stored in linePtr separated by spaces,
+ *	in a form that CreateProcess() understands. Special characters in
+ *	individual arguments from argv[] must be quoted when being stored in
+ *	cmdLine.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+BuildCommandLine(
+    const char *executable,	/* Full path of executable (including
+				 * extension). Replacement for argv[0]. */
+    int argc,			/* Number of arguments. */
+    const char **argv,		/* Argument strings in UTF. */
+    Tcl_DString *linePtr)	/* Initialized Tcl_DString that receives the
+				 * command line (TCHAR). */
+{
+    const char *arg, *start, *special;
+    int quote, i;
+    Tcl_DString ds;
+
+    Tcl_DStringInit(&ds);
+
+    /*
+     * Prime the path. Add a space separator if we were primed with something.
+     */
+
+    TclDStringAppendDString(&ds, linePtr);
+    if (Tcl_DStringLength(linePtr) > 0) {
+	TclDStringAppendLiteral(&ds, " ");
+    }
+
+    for (i = 0; i < argc; i++) {
+	if (i == 0) {
+	    arg = executable;
+	} else {
+	    arg = argv[i];
+	    TclDStringAppendLiteral(&ds, " ");
+	}
+
+	quote = 0;
+	if (arg[0] == '\0') {
+	    quote = 1;
+	} else {
+	    int count;
+	    Tcl_UniChar ch;
+
+	    for (start = arg; *start != '\0'; start += count) {
+		count = Tcl_UtfToUniChar(start, &ch);
+		if (Tcl_UniCharIsSpace(ch)) {	/* INTL: ISO space. */
+		    quote = 1;
+		    break;
+		}
+	    }
+	}
+	if (quote) {
+	    TclDStringAppendLiteral(&ds, "\"");
+	}
+	start = arg;
+	for (special = arg; ; ) {
+	    if ((*special == '\\') && (special[1] == '\\' ||
+		    special[1] == '"' || (quote && special[1] == '\0'))) {
+		Tcl_DStringAppend(&ds, start, (int) (special - start));
+		start = special;
+		while (1) {
+		    special++;
+		    if (*special == '"' || (quote && *special == '\0')) {
+			/*
+			 * N backslashes followed a quote -> insert N * 2 + 1
+			 * backslashes then a quote.
+			 */
+
+			Tcl_DStringAppend(&ds, start,
+				(int) (special - start));
+			break;
+		    }
+		    if (*special != '\\') {
+			break;
+		    }
+		}
+		Tcl_DStringAppend(&ds, start, (int) (special - start));
+		start = special;
+	    }
+	    if (*special == '"') {
+		Tcl_DStringAppend(&ds, start, (int) (special - start));
+		TclDStringAppendLiteral(&ds, "\\\"");
+		start = special + 1;
+	    }
+	    if (*special == '\0') {
+		break;
+	    }
+	    special++;
+	}
+	Tcl_DStringAppend(&ds, start, (int) (special - start));
+	if (quote) {
+	    TclDStringAppendLiteral(&ds, "\"");
+	}
+    }
+    Tcl_DStringFree(linePtr);
+    Tcl_WinUtfToTChar(Tcl_DStringValue(&ds), Tcl_DStringLength(&ds), linePtr);
+    Tcl_DStringFree(&ds);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpCreateCommandChannel --
+ *
+ *	This function is called by Tcl_OpenCommandChannel to perform the
+ *	platform specific channel initialization for a command channel.
+ *
+ * Results:
+ *	Returns a new channel or NULL on failure.
+ *
+ * Side effects:
+ *	Allocates a new channel.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Channel
+TclpCreateCommandChannel(
+    TclFile readFile,		/* If non-null, gives the file for reading. */
+    TclFile writeFile,		/* If non-null, gives the file for writing. */
+    TclFile errorFile,		/* If non-null, gives the file where errors
+				 * can be read. */
+    int numPids,		/* The number of pids in the pid array. */
+    Tcl_Pid *pidPtr)		/* An array of process identifiers. */
+{
+    char channelName[16 + TCL_INTEGER_SPACE];
+    DWORD id;
+    PipeInfo *infoPtr = ckalloc(sizeof(PipeInfo));
+
+    PipeInit();
+
+    infoPtr->watchMask = 0;
+    infoPtr->flags = 0;
+    infoPtr->readFlags = 0;
+    infoPtr->readFile = readFile;
+    infoPtr->writeFile = writeFile;
+    infoPtr->errorFile = errorFile;
+    infoPtr->numPids = numPids;
+    infoPtr->pidPtr = pidPtr;
+    infoPtr->writeBuf = 0;
+    infoPtr->writeBufLen = 0;
+    infoPtr->writeError = 0;
+    infoPtr->channel = NULL;
+
+    infoPtr->validMask = 0;
+
+    infoPtr->threadId = Tcl_GetCurrentThread();
+
+    if (readFile != NULL) {
+	/*
+	 * Start the background reader thread.
+	 */
+
+	infoPtr->readable = CreateEvent(NULL, TRUE, TRUE, NULL);
+	infoPtr->startReader = CreateEvent(NULL, FALSE, FALSE, NULL);
+	infoPtr->stopReader = CreateEvent(NULL, TRUE, FALSE, NULL);
+	infoPtr->readThread = CreateThread(NULL, 256, PipeReaderThread,
+		infoPtr, 0, &id);
+	SetThreadPriority(infoPtr->readThread, THREAD_PRIORITY_HIGHEST);
+	infoPtr->validMask |= TCL_READABLE;
+    } else {
+	infoPtr->readThread = 0;
+    }
+    if (writeFile != NULL) {
+	/*
+	 * Start the background writer thread.
+	 */
+
+	infoPtr->writable = CreateEvent(NULL, TRUE, TRUE, NULL);
+	infoPtr->startWriter = CreateEvent(NULL, FALSE, FALSE, NULL);
+	infoPtr->stopWriter = CreateEvent(NULL, TRUE, FALSE, NULL);
+	infoPtr->writeThread = CreateThread(NULL, 256, PipeWriterThread,
+		infoPtr, 0, &id);
+	SetThreadPriority(infoPtr->readThread, THREAD_PRIORITY_HIGHEST);
+	infoPtr->validMask |= TCL_WRITABLE;
+    }
+
+    /*
+     * For backward compatibility with previous versions of Tcl, we use
+     * "file%d" as the base name for pipes even though it would be more
+     * natural to use "pipe%d". Use the pointer to keep the channel names
+     * unique, in case channels share handles (stdin/stdout).
+     */
+
+    sprintf(channelName, "file%" TCL_I_MODIFIER "x", (size_t) infoPtr);
+    infoPtr->channel = Tcl_CreateChannel(&pipeChannelType, channelName,
+	    infoPtr, infoPtr->validMask);
+
+    /*
+     * Pipes have AUTO translation mode on Windows and ^Z eof char, which
+     * means that a ^Z will be appended to them at close. This is needed for
+     * Windows programs that expect a ^Z at EOF.
+     */
+
+    Tcl_SetChannelOption(NULL, infoPtr->channel, "-translation", "auto");
+    Tcl_SetChannelOption(NULL, infoPtr->channel, "-eofchar", "\032 {}");
+    return infoPtr->channel;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_CreatePipe --
+ *
+ *	System dependent interface to create a pipe for the [chan pipe]
+ *	command. Stolen from TclX.
+ *
+ * Results:
+ *	TCL_OK or TCL_ERROR.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_CreatePipe(
+    Tcl_Interp *interp,		/* Errors returned in result.*/
+    Tcl_Channel *rchan,		/* Where to return the read side. */
+    Tcl_Channel *wchan,		/* Where to return the write side. */
+    int flags)			/* Reserved for future use. */
+{
+    HANDLE readHandle, writeHandle;
+    SECURITY_ATTRIBUTES sec;
+
+    sec.nLength = sizeof(SECURITY_ATTRIBUTES);
+    sec.lpSecurityDescriptor = NULL;
+    sec.bInheritHandle = FALSE;
+
+    if (!CreatePipe(&readHandle, &writeHandle, &sec, 0)) {
+	TclWinConvertError(GetLastError());
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"pipe creation failed: %s", Tcl_PosixError(interp)));
+	return TCL_ERROR;
+    }
+
+    *rchan = Tcl_MakeFileChannel((ClientData) readHandle, TCL_READABLE);
+    Tcl_RegisterChannel(interp, *rchan);
+
+    *wchan = Tcl_MakeFileChannel((ClientData) writeHandle, TCL_WRITABLE);
+    Tcl_RegisterChannel(interp, *wchan);
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclGetAndDetachPids --
+ *
+ *	Stores a list of the command PIDs for a command channel in the
+ *	interp's result.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Modifies the interp's result.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclGetAndDetachPids(
+    Tcl_Interp *interp,
+    Tcl_Channel chan)
+{
+    PipeInfo *pipePtr;
+    const Tcl_ChannelType *chanTypePtr;
+    Tcl_Obj *pidsObj;
+    int i;
+
+    /*
+     * Punt if the channel is not a command channel.
+     */
+
+    chanTypePtr = Tcl_GetChannelType(chan);
+    if (chanTypePtr != &pipeChannelType) {
+	return;
+    }
+
+    pipePtr = Tcl_GetChannelInstanceData(chan);
+    TclNewObj(pidsObj);
+    for (i = 0; i < pipePtr->numPids; i++) {
+	Tcl_ListObjAppendElement(NULL, pidsObj,
+		Tcl_NewWideIntObj((unsigned)
+			TclpGetPid(pipePtr->pidPtr[i])));
+	Tcl_DetachPids(1, &pipePtr->pidPtr[i]);
+    }
+    Tcl_SetObjResult(interp, pidsObj);
+    if (pipePtr->numPids > 0) {
+	ckfree(pipePtr->pidPtr);
+	pipePtr->numPids = 0;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeBlockModeProc --
+ *
+ *	Set blocking or non-blocking mode on channel.
+ *
+ * Results:
+ *	0 if successful, errno when failed.
+ *
+ * Side effects:
+ *	Sets the device into blocking or non-blocking mode.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+PipeBlockModeProc(
+    ClientData instanceData,	/* Instance data for channel. */
+    int mode)			/* TCL_MODE_BLOCKING or
+				 * TCL_MODE_NONBLOCKING. */
+{
+    PipeInfo *infoPtr = (PipeInfo *) instanceData;
+
+    /*
+     * Pipes on Windows can not be switched between blocking and nonblocking,
+     * hence we have to emulate the behavior. This is done in the input
+     * function by checking against a bit in the state. We set or unset the
+     * bit here to cause the input function to emulate the correct behavior.
+     */
+
+    if (mode == TCL_MODE_NONBLOCKING) {
+	infoPtr->flags |= PIPE_ASYNC;
+    } else {
+	infoPtr->flags &= ~(PIPE_ASYNC);
+    }
+    return 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeClose2Proc --
+ *
+ *	Closes a pipe based IO channel.
+ *
+ * Results:
+ *	0 on success, errno otherwise.
+ *
+ * Side effects:
+ *	Closes the physical channel.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+PipeClose2Proc(
+    ClientData instanceData,	/* Pointer to PipeInfo structure. */
+    Tcl_Interp *interp,		/* For error reporting. */
+    int flags)			/* Flags that indicate which side to close. */
+{
+    PipeInfo *pipePtr = (PipeInfo *) instanceData;
+    Tcl_Channel errChan;
+    int errorCode, result;
+    PipeInfo *infoPtr, **nextPtrPtr;
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+    DWORD exitCode;
+
+    errorCode = 0;
+    result = 0;
+
+    if ((!flags || flags == TCL_CLOSE_READ) && (pipePtr->readFile != NULL)) {
+	/*
+	 * Clean up the background thread if necessary. Note that this must be
+	 * done before we can close the file, since the thread may be blocking
+	 * trying to read from the pipe.
+	 */
+
+	if (pipePtr->readThread) {
+	    /*
+	     * The thread may already have closed on its own. Check its exit
+	     * code.
+	     */
+
+	    GetExitCodeThread(pipePtr->readThread, &exitCode);
+
+	    if (exitCode == STILL_ACTIVE) {
+		/*
+		 * Set the stop event so that if the reader thread is blocked
+		 * in PipeReaderThread on WaitForMultipleEvents, it will exit
+		 * cleanly.
+		 */
+
+		SetEvent(pipePtr->stopReader);
+
+		/*
+		 * Wait at most 20 milliseconds for the reader thread to
+		 * close.
+		 */
+
+		if (WaitForSingleObject(pipePtr->readThread,
+			20) == WAIT_TIMEOUT) {
+		    /*
+		     * The thread must be blocked waiting for the pipe to
+		     * become readable in ReadFile(). There isn't a clean way
+		     * to exit the thread from this condition. We should
+		     * terminate the child process instead to get the reader
+		     * thread to fall out of ReadFile with a FALSE. (below) is
+		     * not the correct way to do this, but will stay here
+		     * until a better solution is found.
+		     *
+		     * Note that we need to guard against terminating the
+		     * thread while it is in the middle of Tcl_ThreadAlert
+		     * because it won't be able to release the notifier lock.
+		     */
+
+		    Tcl_MutexLock(&pipeMutex);
+
+		    /* BUG: this leaks memory */
+		    TerminateThread(pipePtr->readThread, 0);
+		    Tcl_MutexUnlock(&pipeMutex);
+		}
+	    }
+
+	    CloseHandle(pipePtr->readThread);
+	    CloseHandle(pipePtr->readable);
+	    CloseHandle(pipePtr->startReader);
+	    CloseHandle(pipePtr->stopReader);
+	    pipePtr->readThread = NULL;
+	}
+	if (TclpCloseFile(pipePtr->readFile) != 0) {
+	    errorCode = errno;
+	}
+	pipePtr->validMask &= ~TCL_READABLE;
+	pipePtr->readFile = NULL;
+    }
+    if ((!flags || flags & TCL_CLOSE_WRITE)
+	    && (pipePtr->writeFile != NULL)) {
+	if (pipePtr->writeThread) {
+	    /*
+	     * Wait for the  writer thread to finish the  current buffer, then
+	     * terminate the thread  and close the handles. If  the channel is
+	     * nonblocking but blocked during  exit, bail out since the worker
+	     * thread is not interruptible and we want TIP#398-fast-exit.
+	     */
+	    if (TclInExit()
+		&& (pipePtr->flags & PIPE_ASYNC)) {
+
+		/* give it a chance to leave honorably */
+		SetEvent(pipePtr->stopWriter);
+
+		if (WaitForSingleObject(pipePtr->writable, 0) == WAIT_TIMEOUT) {
+		    return EWOULDBLOCK;
+		}
+
+	    } else {
+
+		WaitForSingleObject(pipePtr->writable, INFINITE);
+
+	    }
+
+	    /*
+	     * The thread may already have closed on it's own. Check its exit
+	     * code.
+	     */
+
+	    GetExitCodeThread(pipePtr->writeThread, &exitCode);
+
+	    if (exitCode == STILL_ACTIVE) {
+		/*
+		 * Set the stop event so that if the reader thread is blocked
+		 * in PipeReaderThread on WaitForMultipleEvents, it will exit
+		 * cleanly.
+		 */
+
+		SetEvent(pipePtr->stopWriter);
+
+		/*
+		 * Wait at most 20 milliseconds for the reader thread to
+		 * close.
+		 */
+
+		if (WaitForSingleObject(pipePtr->writeThread,
+			20) == WAIT_TIMEOUT) {
+		    /*
+		     * The thread must be blocked waiting for the pipe to
+		     * consume input in WriteFile(). There isn't a clean way
+		     * to exit the thread from this condition. We should
+		     * terminate the child process instead to get the writer
+		     * thread to fall out of WriteFile with a FALSE. (below)
+		     * is not the correct way to do this, but will stay here
+		     * until a better solution is found.
+		     *
+		     * Note that we need to guard against terminating the
+		     * thread while it is in the middle of Tcl_ThreadAlert
+		     * because it won't be able to release the notifier lock.
+		     */
+
+		    Tcl_MutexLock(&pipeMutex);
+
+		    /* BUG: this leaks memory */
+		    TerminateThread(pipePtr->writeThread, 0);
+		    Tcl_MutexUnlock(&pipeMutex);
+		}
+	    }
+
+	    CloseHandle(pipePtr->writeThread);
+	    CloseHandle(pipePtr->writable);
+	    CloseHandle(pipePtr->startWriter);
+	    CloseHandle(pipePtr->stopWriter);
+	    pipePtr->writeThread = NULL;
+	}
+	if (TclpCloseFile(pipePtr->writeFile) != 0) {
+	    if (errorCode == 0) {
+		errorCode = errno;
+	    }
+	}
+	pipePtr->validMask &= ~TCL_WRITABLE;
+	pipePtr->writeFile = NULL;
+    }
+
+    pipePtr->watchMask &= pipePtr->validMask;
+
+    /*
+     * Don't free the channel if any of the flags were set.
+     */
+
+    if (flags) {
+	return errorCode;
+    }
+
+    /*
+     * Remove the file from the list of watched files.
+     */
+
+    for (nextPtrPtr = &(tsdPtr->firstPipePtr), infoPtr = *nextPtrPtr;
+	    infoPtr != NULL;
+	    nextPtrPtr = &infoPtr->nextPtr, infoPtr = *nextPtrPtr) {
+	if (infoPtr == (PipeInfo *)pipePtr) {
+	    *nextPtrPtr = infoPtr->nextPtr;
+	    break;
+	}
+    }
+
+    if ((pipePtr->flags & PIPE_ASYNC) || TclInExit()) {
+	/*
+	 * If the channel is non-blocking or Tcl is being cleaned up, just
+	 * detach the children PIDs, reap them (important if we are in a
+	 * dynamic load module), and discard the errorFile.
+	 */
+
+	Tcl_DetachPids(pipePtr->numPids, pipePtr->pidPtr);
+	Tcl_ReapDetachedProcs();
+
+	if (pipePtr->errorFile) {
+	    if (TclpCloseFile(pipePtr->errorFile) != 0) {
+		if (errorCode == 0) {
+		    errorCode = errno;
+		}
+	    }
+	}
+	result = 0;
+    } else {
+	/*
+	 * Wrap the error file into a channel and give it to the cleanup
+	 * routine.
+	 */
+
+	if (pipePtr->errorFile) {
+	    WinFile *filePtr = (WinFile *) pipePtr->errorFile;
+
+	    errChan = Tcl_MakeFileChannel((ClientData) filePtr->handle,
+		    TCL_READABLE);
+	    ckfree(filePtr);
+	} else {
+	    errChan = NULL;
+	}
+
+	result = TclCleanupChildren(interp, pipePtr->numPids,
+		pipePtr->pidPtr, errChan);
+    }
+
+    if (pipePtr->numPids > 0) {
+	ckfree(pipePtr->pidPtr);
+    }
+
+    if (pipePtr->writeBuf != NULL) {
+	ckfree(pipePtr->writeBuf);
+    }
+
+    ckfree(pipePtr);
+
+    if (errorCode == 0) {
+	return result;
+    }
+    return errorCode;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeInputProc --
+ *
+ *	Reads input from the IO channel into the buffer given. Returns count
+ *	of how many bytes were actually read, and an error indication.
+ *
+ * Results:
+ *	A count of how many bytes were read is returned and an error
+ *	indication is returned in an output argument.
+ *
+ * Side effects:
+ *	Reads input from the actual channel.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+PipeInputProc(
+    ClientData instanceData,	/* Pipe state. */
+    char *buf,			/* Where to store data read. */
+    int bufSize,		/* How much space is available in the
+				 * buffer? */
+    int *errorCode)		/* Where to store error code. */
+{
+    PipeInfo *infoPtr = (PipeInfo *) instanceData;
+    WinFile *filePtr = (WinFile*) infoPtr->readFile;
+    DWORD count, bytesRead = 0;
+    int result;
+
+    *errorCode = 0;
+    /*
+     * Synchronize with the reader thread.
+     */
+
+    result = WaitForRead(infoPtr, (infoPtr->flags & PIPE_ASYNC) ? 0 : 1);
+
+    /*
+     * If an error occurred, return immediately.
+     */
+
+    if (result == -1) {
+	*errorCode = errno;
+	return -1;
+    }
+
+    if (infoPtr->readFlags & PIPE_EXTRABYTE) {
+	/*
+	 * The reader thread consumed 1 byte as a side effect of waiting so we
+	 * need to move it into the buffer.
+	 */
+
+	*buf = infoPtr->extraByte;
+	infoPtr->readFlags &= ~PIPE_EXTRABYTE;
+	buf++;
+	bufSize--;
+	bytesRead = 1;
+
+	/*
+	 * If further read attempts would block, return what we have.
+	 */
+
+	if (result == 0) {
+	    return bytesRead;
+	}
+    }
+
+    /*
+     * Attempt to read bufSize bytes. The read will return immediately if
+     * there is any data available. Otherwise it will block until at least one
+     * byte is available or an EOF occurs.
+     */
+
+    if (ReadFile(filePtr->handle, (LPVOID) buf, (DWORD) bufSize, &count,
+	    (LPOVERLAPPED) NULL) == TRUE) {
+	return bytesRead + count;
+    } else if (bytesRead) {
+	/*
+	 * Ignore errors if we have data to return.
+	 */
+
+	return bytesRead;
+    }
+
+    TclWinConvertError(GetLastError());
+    if (errno == EPIPE) {
+	infoPtr->readFlags |= PIPE_EOF;
+	return 0;
+    }
+    *errorCode = errno;
+    return -1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeOutputProc --
+ *
+ *	Writes the given output on the IO channel. Returns count of how many
+ *	characters were actually written, and an error indication.
+ *
+ * Results:
+ *	A count of how many characters were written is returned and an error
+ *	indication is returned in an output argument.
+ *
+ * Side effects:
+ *	Writes output on the actual channel.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+PipeOutputProc(
+    ClientData instanceData,	/* Pipe state. */
+    const char *buf,		/* The data buffer. */
+    int toWrite,		/* How many bytes to write? */
+    int *errorCode)		/* Where to store error code. */
+{
+    PipeInfo *infoPtr = (PipeInfo *) instanceData;
+    WinFile *filePtr = (WinFile*) infoPtr->writeFile;
+    DWORD bytesWritten, timeout;
+
+    *errorCode = 0;
+    timeout = (infoPtr->flags & PIPE_ASYNC) ? 0 : INFINITE;
+    if (WaitForSingleObject(infoPtr->writable, timeout) == WAIT_TIMEOUT) {
+	/*
+	 * The writer thread is blocked waiting for a write to complete and
+	 * the channel is in non-blocking mode.
+	 */
+
+	errno = EWOULDBLOCK;
+	goto error;
+    }
+
+    /*
+     * Check for a background error on the last write.
+     */
+
+    if (infoPtr->writeError) {
+	TclWinConvertError(infoPtr->writeError);
+	infoPtr->writeError = 0;
+	goto error;
+    }
+
+    if (infoPtr->flags & PIPE_ASYNC) {
+	/*
+	 * The pipe is non-blocking, so copy the data into the output buffer
+	 * and restart the writer thread.
+	 */
+
+	if (toWrite > infoPtr->writeBufLen) {
+	    /*
+	     * Reallocate the buffer to be large enough to hold the data.
+	     */
+
+	    if (infoPtr->writeBuf) {
+		ckfree(infoPtr->writeBuf);
+	    }
+	    infoPtr->writeBufLen = toWrite;
+	    infoPtr->writeBuf = ckalloc(toWrite);
+	}
+	memcpy(infoPtr->writeBuf, buf, (size_t) toWrite);
+	infoPtr->toWrite = toWrite;
+	ResetEvent(infoPtr->writable);
+	SetEvent(infoPtr->startWriter);
+	bytesWritten = toWrite;
+    } else {
+	/*
+	 * In the blocking case, just try to write the buffer directly. This
+	 * avoids an unnecessary copy.
+	 */
+
+	if (WriteFile(filePtr->handle, (LPVOID) buf, (DWORD) toWrite,
+		&bytesWritten, (LPOVERLAPPED) NULL) == FALSE) {
+	    TclWinConvertError(GetLastError());
+	    goto error;
+	}
+    }
+    return bytesWritten;
+
+  error:
+    *errorCode = errno;
+    return -1;
+
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeEventProc --
+ *
+ *	This function is invoked by Tcl_ServiceEvent when a file event reaches
+ *	the front of the event queue. This function invokes Tcl_NotifyChannel
+ *	on the pipe.
+ *
+ * Results:
+ *	Returns 1 if the event was handled, meaning it should be removed from
+ *	the queue. Returns 0 if the event was not handled, meaning it should
+ *	stay on the queue. The only time the event isn't handled is if the
+ *	TCL_FILE_EVENTS flag bit isn't set.
+ *
+ * Side effects:
+ *	Whatever the notifier callback does.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+PipeEventProc(
+    Tcl_Event *evPtr,		/* Event to service. */
+    int flags)			/* Flags that indicate what events to
+				 * handle, such as TCL_FILE_EVENTS. */
+{
+    PipeEvent *pipeEvPtr = (PipeEvent *)evPtr;
+    PipeInfo *infoPtr;
+    int mask;
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    if (!(flags & TCL_FILE_EVENTS)) {
+	return 0;
+    }
+
+    /*
+     * Search through the list of watched pipes for the one whose handle
+     * matches the event. We do this rather than simply dereferencing the
+     * handle in the event so that pipes can be deleted while the event is in
+     * the queue.
+     */
+
+    for (infoPtr = tsdPtr->firstPipePtr; infoPtr != NULL;
+	    infoPtr = infoPtr->nextPtr) {
+	if (pipeEvPtr->infoPtr == infoPtr) {
+	    infoPtr->flags &= ~(PIPE_PENDING);
+	    break;
+	}
+    }
+
+    /*
+     * Remove stale events.
+     */
+
+    if (!infoPtr) {
+	return 1;
+    }
+
+    /*
+     * Check to see if the pipe is readable. Note that we can't tell if a pipe
+     * is writable, so we always report it as being writable unless we have
+     * detected EOF.
+     */
+
+    mask = 0;
+    if ((infoPtr->watchMask & TCL_WRITABLE) &&
+	    (WaitForSingleObject(infoPtr->writable, 0) != WAIT_TIMEOUT)) {
+	mask = TCL_WRITABLE;
+    }
+
+    if ((infoPtr->watchMask & TCL_READABLE) && (WaitForRead(infoPtr,0) >= 0)) {
+	if (infoPtr->readFlags & PIPE_EOF) {
+	    mask = TCL_READABLE;
+	} else {
+	    mask |= TCL_READABLE;
+	}
+    }
+
+    /*
+     * Inform the channel of the events.
+     */
+
+    Tcl_NotifyChannel(infoPtr->channel, infoPtr->watchMask & mask);
+    return 1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeWatchProc --
+ *
+ *	Called by the notifier to set up to watch for events on this channel.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+PipeWatchProc(
+    ClientData instanceData,	/* Pipe state. */
+    int mask)			/* What events to watch for, OR-ed combination
+				 * of TCL_READABLE, TCL_WRITABLE and
+				 * TCL_EXCEPTION. */
+{
+    PipeInfo **nextPtrPtr, *ptr;
+    PipeInfo *infoPtr = (PipeInfo *) instanceData;
+    int oldMask = infoPtr->watchMask;
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    /*
+     * Since most of the work is handled by the background threads, we just
+     * need to update the watchMask and then force the notifier to poll once.
+     */
+
+    infoPtr->watchMask = mask & infoPtr->validMask;
+    if (infoPtr->watchMask) {
+	Tcl_Time blockTime = { 0, 0 };
+	if (!oldMask) {
+	    infoPtr->nextPtr = tsdPtr->firstPipePtr;
+	    tsdPtr->firstPipePtr = infoPtr;
+	}
+	Tcl_SetMaxBlockTime(&blockTime);
+    } else {
+	if (oldMask) {
+	    /*
+	     * Remove the pipe from the list of watched pipes.
+	     */
+
+	    for (nextPtrPtr = &(tsdPtr->firstPipePtr), ptr = *nextPtrPtr;
+		    ptr != NULL;
+		    nextPtrPtr = &ptr->nextPtr, ptr = *nextPtrPtr) {
+		if (infoPtr == ptr) {
+		    *nextPtrPtr = ptr->nextPtr;
+		    break;
+		}
+	    }
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeGetHandleProc --
+ *
+ *	Called from Tcl_GetChannelHandle to retrieve OS handles from inside a
+ *	command pipeline based channel.
+ *
+ * Results:
+ *	Returns TCL_OK with the fd in handlePtr, or TCL_ERROR if there is no
+ *	handle for the specified direction.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+PipeGetHandleProc(
+    ClientData instanceData,	/* The pipe state. */
+    int direction,		/* TCL_READABLE or TCL_WRITABLE */
+    ClientData *handlePtr)	/* Where to store the handle.  */
+{
+    PipeInfo *infoPtr = (PipeInfo *) instanceData;
+    WinFile *filePtr;
+
+    if (direction == TCL_READABLE && infoPtr->readFile) {
+	filePtr = (WinFile*) infoPtr->readFile;
+	*handlePtr = (ClientData) filePtr->handle;
+	return TCL_OK;
+    }
+    if (direction == TCL_WRITABLE && infoPtr->writeFile) {
+	filePtr = (WinFile*) infoPtr->writeFile;
+	*handlePtr = (ClientData) filePtr->handle;
+	return TCL_OK;
+    }
+    return TCL_ERROR;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_WaitPid --
+ *
+ *	Emulates the waitpid system call.
+ *
+ * Results:
+ *	Returns 0 if the process is still alive, -1 on an error, or the pid on
+ *	a clean close.
+ *
+ * Side effects:
+ *	Unless WNOHANG is set and the wait times out, the process information
+ *	record will be deleted and the process handle will be closed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Pid
+Tcl_WaitPid(
+    Tcl_Pid pid,
+    int *statPtr,
+    int options)
+{
+    ProcInfo *infoPtr = NULL, **prevPtrPtr;
+    DWORD flags;
+    Tcl_Pid result;
+    DWORD ret, exitCode;
+
+    PipeInit();
+
+    /*
+     * If no pid is specified, do nothing.
+     */
+
+    if (pid == 0) {
+	*statPtr = 0;
+	return 0;
+    }
+
+    /*
+     * Find the process and cut it from the process list.
+     */
+
+    Tcl_MutexLock(&pipeMutex);
+    prevPtrPtr = &procList;
+    for (infoPtr = procList; infoPtr != NULL;
+	    prevPtrPtr = &infoPtr->nextPtr, infoPtr = infoPtr->nextPtr) {
+	 if (infoPtr->hProcess == (HANDLE) pid) {
+	    *prevPtrPtr = infoPtr->nextPtr;
+	    break;
+	}
+    }
+    Tcl_MutexUnlock(&pipeMutex);
+
+    /*
+     * If the pid is not one of the processes we know about (we started it)
+     * then do nothing.
+     */
+
+    if (infoPtr == NULL) {
+	*statPtr = 0;
+	return 0;
+    }
+
+    /*
+     * Officially "wait" for it to finish. We either poll (WNOHANG) or wait
+     * for an infinite amount of time.
+     */
+
+    if (options & WNOHANG) {
+	flags = 0;
+    } else {
+	flags = INFINITE;
+    }
+    ret = WaitForSingleObject(infoPtr->hProcess, flags);
+    if (ret == WAIT_TIMEOUT) {
+	*statPtr = 0;
+	if (options & WNOHANG) {
+	    /*
+	     * Re-insert this infoPtr back on the list.
+	     */
+
+	    Tcl_MutexLock(&pipeMutex);
+	    infoPtr->nextPtr = procList;
+	    procList = infoPtr;
+	    Tcl_MutexUnlock(&pipeMutex);
+	    return 0;
+	} else {
+	    result = 0;
+	}
+    } else if (ret == WAIT_OBJECT_0) {
+	GetExitCodeProcess(infoPtr->hProcess, &exitCode);
+
+	/*
+	 * Does the exit code look like one of the exception codes?
+	 */
+
+	switch (exitCode) {
+	case EXCEPTION_FLT_DENORMAL_OPERAND:
+	case EXCEPTION_FLT_DIVIDE_BY_ZERO:
+	case EXCEPTION_FLT_INEXACT_RESULT:
+	case EXCEPTION_FLT_INVALID_OPERATION:
+	case EXCEPTION_FLT_OVERFLOW:
+	case EXCEPTION_FLT_STACK_CHECK:
+	case EXCEPTION_FLT_UNDERFLOW:
+	case EXCEPTION_INT_DIVIDE_BY_ZERO:
+	case EXCEPTION_INT_OVERFLOW:
+	    *statPtr = 0xC0000000 | SIGFPE;
+	    break;
+
+	case EXCEPTION_PRIV_INSTRUCTION:
+	case EXCEPTION_ILLEGAL_INSTRUCTION:
+	    *statPtr = 0xC0000000 | SIGILL;
+	    break;
+
+	case EXCEPTION_ACCESS_VIOLATION:
+	case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
+	case EXCEPTION_STACK_OVERFLOW:
+	case EXCEPTION_NONCONTINUABLE_EXCEPTION:
+	case EXCEPTION_INVALID_DISPOSITION:
+	case EXCEPTION_GUARD_PAGE:
+	case EXCEPTION_INVALID_HANDLE:
+	    *statPtr = 0xC0000000 | SIGSEGV;
+	    break;
+
+	case EXCEPTION_DATATYPE_MISALIGNMENT:
+	    *statPtr = 0xC0000000 | SIGBUS;
+	    break;
+
+	case EXCEPTION_BREAKPOINT:
+	case EXCEPTION_SINGLE_STEP:
+	    *statPtr = 0xC0000000 | SIGTRAP;
+	    break;
+
+	case CONTROL_C_EXIT:
+	    *statPtr = 0xC0000000 | SIGINT;
+	    break;
+
+	default:
+	    /*
+	     * Non-exceptional, normal, exit code. Note that the exit code is
+	     * truncated to a signed short range [-32768,32768) whether it
+	     * fits into this range or not.
+	     *
+	     * BUG: Even though the exit code is a DWORD, it is understood by
+	     * convention to be a signed integer, yet there isn't enough room
+	     * to fit this into the POSIX style waitstatus mask without
+	     * truncating it.
+	     */
+
+	    *statPtr = exitCode;
+	    break;
+	}
+	result = pid;
+    } else {
+	errno = ECHILD;
+	*statPtr = 0xC0000000 | ECHILD;
+	result = (Tcl_Pid) -1;
+    }
+
+    /*
+     * Officially close the process handle.
+     */
+
+    CloseHandle(infoPtr->hProcess);
+    ckfree(infoPtr);
+
+    return result;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclWinAddProcess --
+ *
+ *	Add a process to the process list so that we can use Tcl_WaitPid on
+ *	the process.
+ *
+ * Results:
+ *	None
+ *
+ * Side effects:
+ *	Adds the specified process handle to the process list so Tcl_WaitPid
+ *	knows about it.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclWinAddProcess(
+    void *hProcess,		/* Handle to process */
+    unsigned long id)		/* Global process identifier */
+{
+    ProcInfo *procPtr = ckalloc(sizeof(ProcInfo));
+
+    PipeInit();
+
+    procPtr->hProcess = hProcess;
+    procPtr->dwProcessId = id;
+    Tcl_MutexLock(&pipeMutex);
+    procPtr->nextPtr = procList;
+    procList = procPtr;
+    Tcl_MutexUnlock(&pipeMutex);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_PidObjCmd --
+ *
+ *	This function is invoked to process the "pid" Tcl command. See the
+ *	user documentation for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+	/* ARGSUSED */
+int
+Tcl_PidObjCmd(
+    ClientData dummy,		/* Not used. */
+    Tcl_Interp *interp,		/* Current interpreter. */
+    int objc,			/* Number of arguments. */
+    Tcl_Obj *const *objv)	/* Argument strings. */
+{
+    Tcl_Channel chan;
+    const Tcl_ChannelType *chanTypePtr;
+    PipeInfo *pipePtr;
+    int i;
+    Tcl_Obj *resultPtr;
+
+    if (objc > 2) {
+	Tcl_WrongNumArgs(interp, 1, objv, "?channelId?");
+	return TCL_ERROR;
+    }
+    if (objc == 1) {
+	Tcl_SetObjResult(interp, Tcl_NewWideIntObj((unsigned) getpid()));
+    } else {
+	chan = Tcl_GetChannel(interp, Tcl_GetString(objv[1]),
+		NULL);
+	if (chan == (Tcl_Channel) NULL) {
+	    return TCL_ERROR;
+	}
+	chanTypePtr = Tcl_GetChannelType(chan);
+	if (chanTypePtr != &pipeChannelType) {
+	    return TCL_OK;
+	}
+
+	pipePtr = (PipeInfo *) Tcl_GetChannelInstanceData(chan);
+	resultPtr = Tcl_NewObj();
+	for (i = 0; i < pipePtr->numPids; i++) {
+	    Tcl_ListObjAppendElement(/*interp*/ NULL, resultPtr,
+		    Tcl_NewWideIntObj((unsigned)
+			    TclpGetPid(pipePtr->pidPtr[i])));
+	}
+	Tcl_SetObjResult(interp, resultPtr);
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * WaitForRead --
+ *
+ *	Wait until some data is available, the pipe is at EOF or the reader
+ *	thread is blocked waiting for data (if the channel is in non-blocking
+ *	mode).
+ *
+ * Results:
+ *	Returns 1 if pipe is readable. Returns 0 if there is no data on the
+ *	pipe, but there is buffered data. Returns -1 if an error occurred. If
+ *	an error occurred, the threads may not be synchronized.
+ *
+ * Side effects:
+ *	Updates the shared state flags and may consume 1 byte of data from the
+ *	pipe. If no error occurred, the reader thread is blocked waiting for a
+ *	signal from the main thread.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+WaitForRead(
+    PipeInfo *infoPtr,		/* Pipe state. */
+    int blocking)		/* Indicates whether call should be blocking
+				 * or not. */
+{
+    DWORD timeout, count;
+    HANDLE *handle = ((WinFile *) infoPtr->readFile)->handle;
+
+    while (1) {
+	/*
+	 * Synchronize with the reader thread.
+	 */
+
+	timeout = blocking ? INFINITE : 0;
+	if (WaitForSingleObject(infoPtr->readable, timeout) == WAIT_TIMEOUT) {
+	    /*
+	     * The reader thread is blocked waiting for data and the channel
+	     * is in non-blocking mode.
+	     */
+
+	    errno = EWOULDBLOCK;
+	    return -1;
+	}
+
+	/*
+	 * At this point, the two threads are synchronized, so it is safe to
+	 * access shared state.
+	 */
+
+	/*
+	 * If the pipe has hit EOF, it is always readable.
+	 */
+
+	if (infoPtr->readFlags & PIPE_EOF) {
+	    return 1;
+	}
+
+	/*
+	 * Check to see if there is any data sitting in the pipe.
+	 */
+
+	if (PeekNamedPipe(handle, (LPVOID) NULL, (DWORD) 0,
+		(LPDWORD) NULL, &count, (LPDWORD) NULL) != TRUE) {
+	    TclWinConvertError(GetLastError());
+
+	    /*
+	     * Check to see if the peek failed because of EOF.
+	     */
+
+	    if (errno == EPIPE) {
+		infoPtr->readFlags |= PIPE_EOF;
+		return 1;
+	    }
+
+	    /*
+	     * Ignore errors if there is data in the buffer.
+	     */
+
+	    if (infoPtr->readFlags & PIPE_EXTRABYTE) {
+		return 0;
+	    } else {
+		return -1;
+	    }
+	}
+
+	/*
+	 * We found some data in the pipe, so it must be readable.
+	 */
+
+	if (count > 0) {
+	    return 1;
+	}
+
+	/*
+	 * The pipe isn't readable, but there is some data sitting in the
+	 * buffer, so return immediately.
+	 */
+
+	if (infoPtr->readFlags & PIPE_EXTRABYTE) {
+	    return 0;
+	}
+
+	/*
+	 * There wasn't any data available, so reset the thread and try again.
+	 */
+
+	ResetEvent(infoPtr->readable);
+	SetEvent(infoPtr->startReader);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeReaderThread --
+ *
+ *	This function runs in a separate thread and waits for input to become
+ *	available on a pipe.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Signals the main thread when input become available. May cause the
+ *	main thread to wake up by posting a message. May consume one byte from
+ *	the pipe for each wait operation. Will cause a memory leak of ~4k, if
+ *	forcefully terminated with TerminateThread().
+ *
+ *----------------------------------------------------------------------
+ */
+
+static DWORD WINAPI
+PipeReaderThread(
+    LPVOID arg)
+{
+    PipeInfo *infoPtr = (PipeInfo *)arg;
+    HANDLE *handle = ((WinFile *) infoPtr->readFile)->handle;
+    DWORD count, err;
+    int done = 0;
+    HANDLE wEvents[2];
+    DWORD waitResult;
+
+    wEvents[0] = infoPtr->stopReader;
+    wEvents[1] = infoPtr->startReader;
+
+    while (!done) {
+	/*
+	 * Wait for the main thread to signal before attempting to wait on the
+	 * pipe becoming readable.
+	 */
+
+	waitResult = WaitForMultipleObjects(2, wEvents, FALSE, INFINITE);
+
+	if (waitResult != (WAIT_OBJECT_0 + 1)) {
+	    /*
+	     * The start event was not signaled. It might be the stop event or
+	     * an error, so exit.
+	     */
+
+	    break;
+	}
+
+	/*
+	 * Try waiting for 0 bytes. This will block until some data is
+	 * available on NT, but will return immediately on Win 95. So, if no
+	 * data is available after the first read, we block until we can read
+	 * a single byte off of the pipe.
+	 */
+
+	if (ReadFile(handle, NULL, 0, &count, NULL) == FALSE ||
+		PeekNamedPipe(handle, NULL, 0, NULL, &count, NULL) == FALSE) {
+	    /*
+	     * The error is a result of an EOF condition, so set the EOF bit
+	     * before signalling the main thread.
+	     */
+
+	    err = GetLastError();
+	    if (err == ERROR_BROKEN_PIPE) {
+		infoPtr->readFlags |= PIPE_EOF;
+		done = 1;
+	    } else if (err == ERROR_INVALID_HANDLE) {
+		break;
+	    }
+	} else if (count == 0) {
+	    if (ReadFile(handle, &(infoPtr->extraByte), 1, &count, NULL)
+		    != FALSE) {
+		/*
+		 * One byte was consumed as a side effect of waiting for the
+		 * pipe to become readable.
+		 */
+
+		infoPtr->readFlags |= PIPE_EXTRABYTE;
+	    } else {
+		err = GetLastError();
+		if (err == ERROR_BROKEN_PIPE) {
+		    /*
+		     * The error is a result of an EOF condition, so set the
+		     * EOF bit before signalling the main thread.
+		     */
+
+		    infoPtr->readFlags |= PIPE_EOF;
+		    done = 1;
+		} else if (err == ERROR_INVALID_HANDLE) {
+		    break;
+		}
+	    }
+	}
+
+
+	/*
+	 * Signal the main thread by signalling the readable event and then
+	 * waking up the notifier thread.
+	 */
+
+	SetEvent(infoPtr->readable);
+
+	/*
+	 * Alert the foreground thread. Note that we need to treat this like a
+	 * critical section so the foreground thread does not terminate this
+	 * thread while we are holding a mutex in the notifier code.
+	 */
+
+	Tcl_MutexLock(&pipeMutex);
+	if (infoPtr->threadId != NULL) {
+	    /*
+	     * TIP #218. When in flight ignore the event, no one will receive
+	     * it anyway.
+	     */
+
+	    Tcl_ThreadAlert(infoPtr->threadId);
+	}
+	Tcl_MutexUnlock(&pipeMutex);
+    }
+
+    return 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeWriterThread --
+ *
+ *	This function runs in a separate thread and writes data onto a pipe.
+ *
+ * Results:
+ *	Always returns 0.
+ *
+ * Side effects:
+ *	Signals the main thread when an output operation is completed. May
+ *	cause the main thread to wake up by posting a message.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static DWORD WINAPI
+PipeWriterThread(
+    LPVOID arg)
+{
+    PipeInfo *infoPtr = (PipeInfo *)arg;
+    HANDLE *handle = ((WinFile *) infoPtr->writeFile)->handle;
+    DWORD count, toWrite;
+    char *buf;
+    int done = 0;
+    HANDLE wEvents[2];
+    DWORD waitResult;
+
+    wEvents[0] = infoPtr->stopWriter;
+    wEvents[1] = infoPtr->startWriter;
+
+    while (!done) {
+	/*
+	 * Wait for the main thread to signal before attempting to write.
+	 */
+
+	waitResult = WaitForMultipleObjects(2, wEvents, FALSE, INFINITE);
+
+	if (waitResult != (WAIT_OBJECT_0 + 1)) {
+	    /*
+	     * The start event was not signaled. It might be the stop event or
+	     * an error, so exit.
+	     */
+
+	    if (waitResult == WAIT_OBJECT_0) {
+		SetEvent(infoPtr->writable);
+	    }
+
+	    break;
+	}
+
+	buf = infoPtr->writeBuf;
+	toWrite = infoPtr->toWrite;
+
+	/*
+	 * Loop until all of the bytes are written or an error occurs.
+	 */
+
+	while (toWrite > 0) {
+	    if (WriteFile(handle, buf, toWrite, &count, NULL) == FALSE) {
+		infoPtr->writeError = GetLastError();
+		done = 1;
+		break;
+	    } else {
+		toWrite -= count;
+		buf += count;
+	    }
+	}
+
+	/*
+	 * Signal the main thread by signalling the writable event and then
+	 * waking up the notifier thread.
+	 */
+
+	SetEvent(infoPtr->writable);
+
+	/*
+	 * Alert the foreground thread. Note that we need to treat this like a
+	 * critical section so the foreground thread does not terminate this
+	 * thread while we are holding a mutex in the notifier code.
+	 */
+
+	Tcl_MutexLock(&pipeMutex);
+	if (infoPtr->threadId != NULL) {
+	    /*
+	     * TIP #218. When in flight ignore the event, no one will receive
+	     * it anyway.
+	     */
+
+	    Tcl_ThreadAlert(infoPtr->threadId);
+	}
+	Tcl_MutexUnlock(&pipeMutex);
+    }
+
+    return 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PipeThreadActionProc --
+ *
+ *	Insert or remove any thread local refs to this channel.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Changes thread local list of valid channels.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+PipeThreadActionProc(
+    ClientData instanceData,
+    int action)
+{
+    PipeInfo *infoPtr = (PipeInfo *) instanceData;
+
+    /*
+     * We do not access firstPipePtr in the thread structures. This is not for
+     * all pipes managed by the thread, but only those we are watching.
+     * Removal of the filevent handlers before transfer thus takes care of
+     * this structure.
+     */
+
+    Tcl_MutexLock(&pipeMutex);
+    if (action == TCL_CHANNEL_THREAD_INSERT) {
+	/*
+	 * We can't copy the thread information from the channel when the
+	 * channel is created. At this time the channel back pointer has not
+	 * been set yet. However in that case the threadId has already been
+	 * set by TclpCreateCommandChannel itself, so the structure is still
+	 * good.
+	 */
+
+	PipeInit();
+	if (infoPtr->channel != NULL) {
+	    infoPtr->threadId = Tcl_GetChannelThread(infoPtr->channel);
+	}
+    } else {
+	infoPtr->threadId = NULL;
+    }
+    Tcl_MutexUnlock(&pipeMutex);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpOpenTemporaryFile --
+ *
+ *	Creates a temporary file, possibly based on the supplied bits and
+ *	pieces of template supplied in the first three arguments. If the
+ *	fourth argument is non-NULL, it contains a Tcl_Obj to store the name
+ *	of the temporary file in (and it is caller's responsibility to clean
+ *	up). If the fourth argument is NULL, try to arrange for the temporary
+ *	file to go away once it is no longer needed.
+ *
+ * Results:
+ *	A read-write Tcl Channel open on the file.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Channel
+TclpOpenTemporaryFile(
+    Tcl_Obj *dirObj,
+    Tcl_Obj *basenameObj,
+    Tcl_Obj *extensionObj,
+    Tcl_Obj *resultingNameObj)
+{
+    TCHAR name[MAX_PATH];
+    char *namePtr;
+    HANDLE handle;
+    DWORD flags = FILE_ATTRIBUTE_TEMPORARY;
+    int length, counter, counter2;
+    Tcl_DString buf;
+
+    if (!resultingNameObj) {
+	flags |= FILE_FLAG_DELETE_ON_CLOSE;
+    }
+
+    namePtr = (char *) name;
+    length = GetTempPath(MAX_PATH, name);
+    if (length == 0) {
+	goto gotError;
+    }
+    namePtr += length * sizeof(TCHAR);
+    if (basenameObj) {
+	const char *string = Tcl_GetString(basenameObj);
+
+	Tcl_WinUtfToTChar(string, basenameObj->length, &buf);
+	memcpy(namePtr, Tcl_DStringValue(&buf), Tcl_DStringLength(&buf));
+	namePtr += Tcl_DStringLength(&buf);
+	Tcl_DStringFree(&buf);
+    } else {
+	const TCHAR *baseStr = TEXT("TCL");
+	int length = 3 * sizeof(TCHAR);
+
+	memcpy(namePtr, baseStr, length);
+	namePtr += length;
+    }
+    counter = TclpGetClicks() % 65533;
+    counter2 = 1024;			/* Only try this many times! Prevents
+					 * an infinite loop. */
+
+    do {
+	char number[TCL_INTEGER_SPACE + 4];
+
+	sprintf(number, "%d.TMP", counter);
+	counter = (unsigned short) (counter + 1);
+	Tcl_WinUtfToTChar(number, strlen(number), &buf);
+	Tcl_DStringSetLength(&buf, Tcl_DStringLength(&buf) + 1);
+	memcpy(namePtr, Tcl_DStringValue(&buf), Tcl_DStringLength(&buf) + 1);
+	Tcl_DStringFree(&buf);
+
+	handle = CreateFile(name,
+		GENERIC_READ|GENERIC_WRITE, 0, NULL, CREATE_NEW, flags, NULL);
+    } while (handle == INVALID_HANDLE_VALUE
+	    && --counter2 > 0
+	    && GetLastError() == ERROR_FILE_EXISTS);
+    if (handle == INVALID_HANDLE_VALUE) {
+	goto gotError;
+    }
+
+    if (resultingNameObj) {
+	Tcl_Obj *tmpObj = TclpNativeToNormalized(name);
+
+	Tcl_AppendObjToObj(resultingNameObj, tmpObj);
+	TclDecrRefCount(tmpObj);
+    }
+
+    return Tcl_MakeFileChannel((ClientData) handle,
+	    TCL_READABLE|TCL_WRITABLE);
+
+  gotError:
+    TclWinConvertError(GetLastError());
+    return NULL;
+}
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */