Merge commit '9966985d896629eede849a84f18e406d1164a16c' as 'tcl8.6'

1 files changed, 1588 insertions, 0 deletions

diff --git a/tcl8.6/win/tclWinChan.c b/tcl8.6/win/tclWinChan.c
new file mode 100644
index 0000000..78b510b
--- /dev/null
+++ b/tcl8.6/win/tclWinChan.c
@@ -0,0 +1,1588 @@
+/*
+ * tclWinChan.c
+ *
+ *	Channel drivers for Windows channels based on files, command pipes and
+ *	TCP sockets.
+ *
+ * Copyright (c) 1995-1997 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"
+#include "tclIO.h"
+
+/*
+ * State flags used in the info structures below.
+ */
+
+#define FILE_PENDING	(1<<0)	/* Message is pending in the queue. */
+#define FILE_ASYNC	(1<<1)	/* Channel is non-blocking. */
+#define FILE_APPEND	(1<<2)	/* File is in append mode. */
+
+#define FILE_TYPE_SERIAL  (FILE_TYPE_PIPE+1)
+#define FILE_TYPE_CONSOLE (FILE_TYPE_PIPE+2)
+
+/*
+ * The following structure contains per-instance data for a file based channel.
+ */
+
+typedef struct FileInfo {
+    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. */
+    HANDLE handle;		/* Input/output file. */
+    struct FileInfo *nextPtr;	/* Pointer to next registered file. */
+    int dirty;			/* Boolean flag. Set if the OS may have data
+				 * pending on the channel. */
+} FileInfo;
+
+typedef struct ThreadSpecificData {
+    /*
+     * List of all file channels currently open.
+     */
+
+    FileInfo *firstFilePtr;
+} ThreadSpecificData;
+
+static Tcl_ThreadDataKey dataKey;
+
+/*
+ * The following structure is what is added to the Tcl event queue when file
+ * events are generated.
+ */
+
+typedef struct FileEvent {
+    Tcl_Event header;		/* Information that is standard for all
+				 * events. */
+    FileInfo *infoPtr;		/* Pointer to file info structure. Note that
+				 * we still have to verify that the file
+				 * exists before dereferencing this
+				 * pointer. */
+} FileEvent;
+
+/*
+ * Static routines for this file:
+ */
+
+static int		FileBlockProc(ClientData instanceData, int mode);
+static void		FileChannelExitHandler(ClientData clientData);
+static void		FileCheckProc(ClientData clientData, int flags);
+static int		FileCloseProc(ClientData instanceData,
+			    Tcl_Interp *interp);
+static int		FileEventProc(Tcl_Event *evPtr, int flags);
+static int		FileGetHandleProc(ClientData instanceData,
+			    int direction, ClientData *handlePtr);
+static ThreadSpecificData *FileInit(void);
+static int		FileInputProc(ClientData instanceData, char *buf,
+			    int toRead, int *errorCode);
+static int		FileOutputProc(ClientData instanceData,
+			    const char *buf, int toWrite, int *errorCode);
+static int		FileSeekProc(ClientData instanceData, long offset,
+			    int mode, int *errorCode);
+static Tcl_WideInt	FileWideSeekProc(ClientData instanceData,
+			    Tcl_WideInt offset, int mode, int *errorCode);
+static void		FileSetupProc(ClientData clientData, int flags);
+static void		FileWatchProc(ClientData instanceData, int mask);
+static void		FileThreadActionProc(ClientData instanceData,
+			    int action);
+static int		FileTruncateProc(ClientData instanceData,
+			    Tcl_WideInt length);
+static DWORD		FileGetType(HANDLE handle);
+static int		NativeIsComPort(const TCHAR *nativeName);
+/*
+ * This structure describes the channel type structure for file based IO.
+ */
+
+static const Tcl_ChannelType fileChannelType = {
+    "file",			/* Type name. */
+    TCL_CHANNEL_VERSION_5,	/* v5 channel */
+    FileCloseProc,		/* Close proc. */
+    FileInputProc,		/* Input proc. */
+    FileOutputProc,		/* Output proc. */
+    FileSeekProc,		/* Seek proc. */
+    NULL,			/* Set option proc. */
+    NULL,			/* Get option proc. */
+    FileWatchProc,		/* Set up the notifier to watch the channel. */
+    FileGetHandleProc,		/* Get an OS handle from channel. */
+    NULL,			/* close2proc. */
+    FileBlockProc,		/* Set blocking or non-blocking mode.*/
+    NULL,			/* flush proc. */
+    NULL,			/* handler proc. */
+    FileWideSeekProc,		/* Wide seek proc. */
+    FileThreadActionProc,	/* Thread action proc. */
+    FileTruncateProc		/* Truncate proc. */
+};
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileInit --
+ *
+ *	This function creates the window used to simulate file events.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Creates a new window and creates an exit handler.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static ThreadSpecificData *
+FileInit(void)
+{
+    ThreadSpecificData *tsdPtr =
+	    (ThreadSpecificData *)TclThreadDataKeyGet(&dataKey);
+
+    if (tsdPtr == NULL) {
+	tsdPtr = TCL_TSD_INIT(&dataKey);
+	tsdPtr->firstFilePtr = NULL;
+	Tcl_CreateEventSource(FileSetupProc, FileCheckProc, NULL);
+	Tcl_CreateThreadExitHandler(FileChannelExitHandler, NULL);
+    }
+    return tsdPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileChannelExitHandler --
+ *
+ *	This function is called to cleanup the channel driver before Tcl is
+ *	unloaded.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Destroys the communication window.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+FileChannelExitHandler(
+    ClientData clientData)	/* Old window proc */
+{
+    Tcl_DeleteEventSource(FileSetupProc, FileCheckProc, NULL);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileSetupProc --
+ *
+ *	This function is invoked before Tcl_DoOneEvent blocks waiting for an
+ *	event.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Adjusts the block time if needed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+FileSetupProc(
+    ClientData data,		/* Not used. */
+    int flags)			/* Event flags as passed to Tcl_DoOneEvent. */
+{
+    FileInfo *infoPtr;
+    Tcl_Time blockTime = { 0, 0 };
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    if (!(flags & TCL_FILE_EVENTS)) {
+	return;
+    }
+
+    /*
+     * Check to see if there is a ready file. If so, poll.
+     */
+
+    for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL;
+	    infoPtr = infoPtr->nextPtr) {
+	if (infoPtr->watchMask) {
+	    Tcl_SetMaxBlockTime(&blockTime);
+	    break;
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileCheckProc --
+ *
+ *	This function is called by Tcl_DoOneEvent to check the file event
+ *	source for events.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	May queue an event.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+FileCheckProc(
+    ClientData data,		/* Not used. */
+    int flags)			/* Event flags as passed to Tcl_DoOneEvent. */
+{
+    FileEvent *evPtr;
+    FileInfo *infoPtr;
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    if (!(flags & TCL_FILE_EVENTS)) {
+	return;
+    }
+
+    /*
+     * Queue events for any ready files that don't already have events queued
+     * (caused by persistent states that won't generate WinSock events).
+     */
+
+    for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL;
+	    infoPtr = infoPtr->nextPtr) {
+	if (infoPtr->watchMask && !(infoPtr->flags & FILE_PENDING)) {
+	    infoPtr->flags |= FILE_PENDING;
+	    evPtr = ckalloc(sizeof(FileEvent));
+	    evPtr->header.proc = FileEventProc;
+	    evPtr->infoPtr = infoPtr;
+	    Tcl_QueueEvent((Tcl_Event *) evPtr, TCL_QUEUE_TAIL);
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileEventProc --
+ *
+ *	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 file.
+ *
+ * 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
+FileEventProc(
+    Tcl_Event *evPtr,		/* Event to service. */
+    int flags)			/* Flags that indicate what events to handle,
+				 * such as TCL_FILE_EVENTS. */
+{
+    FileEvent *fileEvPtr = (FileEvent *)evPtr;
+    FileInfo *infoPtr;
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    if (!(flags & TCL_FILE_EVENTS)) {
+	return 0;
+    }
+
+    /*
+     * Search through the list of watched files for the one whose handle
+     * matches the event. We do this rather than simply dereferencing the
+     * handle in the event so that files can be deleted while the event is in
+     * the queue.
+     */
+
+    for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL;
+	    infoPtr = infoPtr->nextPtr) {
+	if (fileEvPtr->infoPtr == infoPtr) {
+	    infoPtr->flags &= ~(FILE_PENDING);
+	    Tcl_NotifyChannel(infoPtr->channel, infoPtr->watchMask);
+	    break;
+	}
+    }
+    return 1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileBlockProc --
+ *
+ *	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
+FileBlockProc(
+    ClientData instanceData,	/* Instance data for channel. */
+    int mode)			/* TCL_MODE_BLOCKING or
+				 * TCL_MODE_NONBLOCKING. */
+{
+    FileInfo *infoPtr = instanceData;
+
+    /*
+     * Files 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 |= FILE_ASYNC;
+    } else {
+	infoPtr->flags &= ~(FILE_ASYNC);
+    }
+    return 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileCloseProc --
+ *
+ *	Closes the IO channel.
+ *
+ * Results:
+ *	0 if successful, the value of errno if failed.
+ *
+ * Side effects:
+ *	Closes the physical channel
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+FileCloseProc(
+    ClientData instanceData,	/* Pointer to FileInfo structure. */
+    Tcl_Interp *interp)		/* Not used. */
+{
+    FileInfo *fileInfoPtr = instanceData;
+    FileInfo *infoPtr;
+    ThreadSpecificData *tsdPtr;
+    int errorCode = 0;
+
+    /*
+     * Remove the file from the watch list.
+     */
+
+    FileWatchProc(instanceData, 0);
+
+    /*
+     * 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) != fileInfoPtr->handle)
+	    &&  (GetStdHandle(STD_OUTPUT_HANDLE) != fileInfoPtr->handle)
+	    &&  (GetStdHandle(STD_ERROR_HANDLE) != fileInfoPtr->handle))) {
+	if (CloseHandle(fileInfoPtr->handle) == FALSE) {
+	    TclWinConvertError(GetLastError());
+	    errorCode = errno;
+	}
+    }
+
+    /*
+     * See if this FileInfo* is still on the thread local list.
+     */
+
+    tsdPtr = TCL_TSD_INIT(&dataKey);
+    for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL;
+	    infoPtr = infoPtr->nextPtr) {
+	if (infoPtr == fileInfoPtr) {
+	    /*
+	     * This channel exists on the thread local list. It should have
+	     * been removed by an earlier Threadaction call, but do that now
+	     * since just deallocating fileInfoPtr would leave an deallocated
+	     * pointer on the thread local list.
+	     */
+
+	    FileThreadActionProc(fileInfoPtr,TCL_CHANNEL_THREAD_REMOVE);
+	    break;
+	}
+    }
+    ckfree(fileInfoPtr);
+    return errorCode;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileSeekProc --
+ *
+ *	Seeks on a file-based channel. Returns the new position.
+ *
+ * Results:
+ *	-1 if failed, the new position if successful. If failed, it also sets
+ *	*errorCodePtr to the error code.
+ *
+ * Side effects:
+ *	Moves the location at which the channel will be accessed in future
+ *	operations.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+FileSeekProc(
+    ClientData instanceData,	/* File state. */
+    long offset,		/* Offset to seek to. */
+    int mode,			/* Relative to where should we seek? */
+    int *errorCodePtr)		/* To store error code. */
+{
+    FileInfo *infoPtr = instanceData;
+    LONG newPos, newPosHigh, oldPos, oldPosHigh;
+    DWORD moveMethod;
+
+    *errorCodePtr = 0;
+    if (mode == SEEK_SET) {
+	moveMethod = FILE_BEGIN;
+    } else if (mode == SEEK_CUR) {
+	moveMethod = FILE_CURRENT;
+    } else {
+	moveMethod = FILE_END;
+    }
+
+    /*
+     * Save our current place in case we need to roll-back the seek.
+     */
+
+    oldPosHigh = 0;
+    oldPos = SetFilePointer(infoPtr->handle, 0, &oldPosHigh, FILE_CURRENT);
+    if (oldPos == (LONG)INVALID_SET_FILE_POINTER) {
+	DWORD winError = GetLastError();
+
+	if (winError != NO_ERROR) {
+	    TclWinConvertError(winError);
+	    *errorCodePtr = errno;
+	    return -1;
+	}
+    }
+
+    newPosHigh = (offset < 0 ? -1 : 0);
+    newPos = SetFilePointer(infoPtr->handle, offset, &newPosHigh, moveMethod);
+    if (newPos == (LONG)INVALID_SET_FILE_POINTER) {
+	DWORD winError = GetLastError();
+
+	if (winError != NO_ERROR) {
+	    TclWinConvertError(winError);
+	    *errorCodePtr = errno;
+	    return -1;
+	}
+    }
+
+    /*
+     * Check for expressability in our return type, and roll-back otherwise.
+     */
+
+    if (newPosHigh != 0) {
+	*errorCodePtr = EOVERFLOW;
+	SetFilePointer(infoPtr->handle, oldPos, &oldPosHigh, FILE_BEGIN);
+	return -1;
+    }
+    return (int) newPos;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileWideSeekProc --
+ *
+ *	Seeks on a file-based channel. Returns the new position.
+ *
+ * Results:
+ *	-1 if failed, the new position if successful. If failed, it also sets
+ *	*errorCodePtr to the error code.
+ *
+ * Side effects:
+ *	Moves the location at which the channel will be accessed in future
+ *	operations.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static Tcl_WideInt
+FileWideSeekProc(
+    ClientData instanceData,	/* File state. */
+    Tcl_WideInt offset,		/* Offset to seek to. */
+    int mode,			/* Relative to where should we seek? */
+    int *errorCodePtr)		/* To store error code. */
+{
+    FileInfo *infoPtr = instanceData;
+    DWORD moveMethod;
+    LONG newPos, newPosHigh;
+
+    *errorCodePtr = 0;
+    if (mode == SEEK_SET) {
+	moveMethod = FILE_BEGIN;
+    } else if (mode == SEEK_CUR) {
+	moveMethod = FILE_CURRENT;
+    } else {
+	moveMethod = FILE_END;
+    }
+
+    newPosHigh = Tcl_WideAsLong(offset >> 32);
+    newPos = SetFilePointer(infoPtr->handle, Tcl_WideAsLong(offset),
+	    &newPosHigh, moveMethod);
+    if (newPos == (LONG)INVALID_SET_FILE_POINTER) {
+	DWORD winError = GetLastError();
+
+	if (winError != NO_ERROR) {
+	    TclWinConvertError(winError);
+	    *errorCodePtr = errno;
+	    return -1;
+	}
+    }
+    return (((Tcl_WideInt)((unsigned)newPos)) | (Tcl_LongAsWide(newPosHigh) << 32));
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileTruncateProc --
+ *
+ *	Truncates a file-based channel. Returns the error code.
+ *
+ * Results:
+ *	0 if successful, POSIX-y error code if it failed.
+ *
+ * Side effects:
+ *	Truncates the file, may move file pointers too.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+FileTruncateProc(
+    ClientData instanceData,	/* File state. */
+    Tcl_WideInt length)		/* Length to truncate at. */
+{
+    FileInfo *infoPtr = instanceData;
+    LONG newPos, newPosHigh, oldPos, oldPosHigh;
+
+    /*
+     * Save where we were...
+     */
+
+    oldPosHigh = 0;
+    oldPos = SetFilePointer(infoPtr->handle, 0, &oldPosHigh, FILE_CURRENT);
+    if (oldPos == (LONG)INVALID_SET_FILE_POINTER) {
+	DWORD winError = GetLastError();
+	if (winError != NO_ERROR) {
+	    TclWinConvertError(winError);
+	    return errno;
+	}
+    }
+
+    /*
+     * Move to where we want to truncate
+     */
+
+    newPosHigh = Tcl_WideAsLong(length >> 32);
+    newPos = SetFilePointer(infoPtr->handle, Tcl_WideAsLong(length),
+	    &newPosHigh, FILE_BEGIN);
+    if (newPos == (LONG)INVALID_SET_FILE_POINTER) {
+	DWORD winError = GetLastError();
+	if (winError != NO_ERROR) {
+	    TclWinConvertError(winError);
+	    return errno;
+	}
+    }
+
+    /*
+     * Perform the truncation (unlike POSIX ftruncate(), we needed to move to
+     * the location to truncate at first).
+     */
+
+    if (!SetEndOfFile(infoPtr->handle)) {
+	TclWinConvertError(GetLastError());
+	return errno;
+    }
+
+    /*
+     * Move back. If this last step fails, we don't care; it's just a "best
+     * effort" attempt to restore our file pointer to where it was.
+     */
+
+    SetFilePointer(infoPtr->handle, oldPos, &oldPosHigh, FILE_BEGIN);
+    return 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileInputProc --
+ *
+ *	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
+FileInputProc(
+    ClientData instanceData,	/* File state. */
+    char *buf,			/* Where to store data read. */
+    int bufSize,		/* Num bytes available in buffer. */
+    int *errorCode)		/* Where to store error code. */
+{
+    FileInfo *infoPtr = instanceData;
+    DWORD bytesRead;
+
+    *errorCode = 0;
+
+    /*
+     * TODO: This comment appears to be out of date.  We *do* have a
+     * console driver, over in tclWinConsole.c.  After some Windows
+     * developer confirms, this comment should be revised.
+     *
+     * Note that we will block on reads from a console buffer until a full
+     * line has been entered. The only way I know of to get around this is to
+     * write a console driver. We should probably do this at some point, but
+     * for now, we just block. The same problem exists for files being read
+     * over the network.
+     */
+
+    if (ReadFile(infoPtr->handle, (LPVOID) buf, (DWORD) bufSize, &bytesRead,
+	    (LPOVERLAPPED) NULL) != FALSE) {
+	return bytesRead;
+    }
+
+    TclWinConvertError(GetLastError());
+    *errorCode = errno;
+    if (errno == EPIPE) {
+	return 0;
+    }
+    return -1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileOutputProc --
+ *
+ *	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
+FileOutputProc(
+    ClientData instanceData,	/* File state. */
+    const char *buf,		/* The data buffer. */
+    int toWrite,		/* How many bytes to write? */
+    int *errorCode)		/* Where to store error code. */
+{
+    FileInfo *infoPtr = instanceData;
+    DWORD bytesWritten;
+
+    *errorCode = 0;
+
+    /*
+     * If we are writing to a file that was opened with O_APPEND, we need to
+     * seek to the end of the file before writing the current buffer.
+     */
+
+    if (infoPtr->flags & FILE_APPEND) {
+	SetFilePointer(infoPtr->handle, 0, NULL, FILE_END);
+    }
+
+    if (WriteFile(infoPtr->handle, (LPVOID) buf, (DWORD) toWrite,
+	    &bytesWritten, (LPOVERLAPPED) NULL) == FALSE) {
+	TclWinConvertError(GetLastError());
+	*errorCode = errno;
+	return -1;
+    }
+    infoPtr->dirty = 1;
+    return bytesWritten;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileWatchProc --
+ *
+ *	Called by the notifier to set up to watch for events on this channel.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+FileWatchProc(
+    ClientData instanceData,	/* File state. */
+    int mask)			/* What events to watch for; OR-ed combination
+				 * of TCL_READABLE, TCL_WRITABLE and
+				 * TCL_EXCEPTION. */
+{
+    FileInfo *infoPtr = instanceData;
+    Tcl_Time blockTime = { 0, 0 };
+
+    /*
+     * Since the file is always ready for events, we set the block time to
+     * zero so we will poll.
+     */
+
+    infoPtr->watchMask = mask & infoPtr->validMask;
+    if (infoPtr->watchMask) {
+	Tcl_SetMaxBlockTime(&blockTime);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileGetHandleProc --
+ *
+ *	Called from Tcl_GetChannelHandle to retrieve OS handles from a file
+ *	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
+FileGetHandleProc(
+    ClientData instanceData,	/* The file state. */
+    int direction,		/* TCL_READABLE or TCL_WRITABLE */
+    ClientData *handlePtr)	/* Where to store the handle.  */
+{
+    FileInfo *infoPtr = instanceData;
+
+    if (direction & infoPtr->validMask) {
+	*handlePtr = (ClientData) infoPtr->handle;
+	return TCL_OK;
+    } else {
+	return TCL_ERROR;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpOpenFileChannel --
+ *
+ *	Open an File based channel on Unix systems.
+ *
+ * Results:
+ *	The new channel or NULL. If NULL, the output argument errorCodePtr is
+ *	set to a POSIX error.
+ *
+ * Side effects:
+ *	May open the channel and may cause creation of a file on the file
+ *	system.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Channel
+TclpOpenFileChannel(
+    Tcl_Interp *interp,		/* Interpreter for error reporting; can be
+				 * NULL. */
+    Tcl_Obj *pathPtr,		/* Name of file to open. */
+    int mode,			/* POSIX mode. */
+    int permissions)		/* If the open involves creating a file, with
+				 * what modes to create it? */
+{
+    Tcl_Channel channel = 0;
+    int channelPermissions = 0;
+    DWORD accessMode = 0, createMode, shareMode, flags;
+    const TCHAR *nativeName;
+    HANDLE handle;
+    char channelName[16 + TCL_INTEGER_SPACE];
+    TclFile readFile = NULL, writeFile = NULL;
+
+    nativeName = Tcl_FSGetNativePath(pathPtr);
+    if (nativeName == NULL) {
+	if (interp != (Tcl_Interp *) NULL) {
+	    Tcl_AppendResult(interp, "couldn't open \"",
+	    TclGetString(pathPtr), "\": filename is invalid on this platform",
+	    NULL);
+	}
+	return NULL;
+    }
+
+    switch (mode & (O_RDONLY | O_WRONLY | O_RDWR)) {
+    case O_RDONLY:
+	accessMode = GENERIC_READ;
+	channelPermissions = TCL_READABLE;
+	break;
+    case O_WRONLY:
+	accessMode = GENERIC_WRITE;
+	channelPermissions = TCL_WRITABLE;
+	break;
+    case O_RDWR:
+	accessMode = (GENERIC_READ | GENERIC_WRITE);
+	channelPermissions = (TCL_READABLE | TCL_WRITABLE);
+	break;
+    default:
+	Tcl_Panic("TclpOpenFileChannel: invalid mode value");
+	break;
+    }
+
+    /*
+     * 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;
+    }
+
+    /*
+     * [2413550] Avoid double-open of serial ports on Windows
+     * Special handling for Windows serial ports by a "name-hint"
+     * to directly open it with the OVERLAPPED flag set.
+     */
+
+    if( NativeIsComPort(nativeName) ) {
+
+	handle = TclWinSerialOpen(INVALID_HANDLE_VALUE, nativeName, accessMode);
+	if (handle == INVALID_HANDLE_VALUE) {
+	    TclWinConvertError(GetLastError());
+	    if (interp != (Tcl_Interp *) NULL) {
+		Tcl_AppendResult(interp, "couldn't open serial \"",
+			TclGetString(pathPtr), "\": ",
+			Tcl_PosixError(interp), NULL);
+	    }
+	    return NULL;
+	}
+
+	/*
+	* For natively named Windows serial ports we are done.
+	*/
+	channel = TclWinOpenSerialChannel(handle, channelName,
+		channelPermissions);
+
+	return channel;
+    }
+    /*
+     * If the file is being created, get the file attributes from the
+     * permissions argument, else use the existing file attributes.
+     */
+
+    if (mode & O_CREAT) {
+	if (permissions & S_IWRITE) {
+	    flags = FILE_ATTRIBUTE_NORMAL;
+	} else {
+	    flags = FILE_ATTRIBUTE_READONLY;
+	}
+    } else {
+	flags = GetFileAttributes(nativeName);
+	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(nativeName, accessMode, shareMode,
+	    NULL, createMode, flags, (HANDLE) NULL);
+
+    if (handle == INVALID_HANDLE_VALUE) {
+	DWORD err = GetLastError();
+
+	if ((err & 0xffffL) == ERROR_OPEN_FAILED) {
+	    err = (mode & O_CREAT) ? ERROR_FILE_EXISTS : ERROR_FILE_NOT_FOUND;
+	}
+	TclWinConvertError(err);
+	if (interp != (Tcl_Interp *) NULL) {
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "couldn't open \"%s\": %s",
+		    TclGetString(pathPtr), Tcl_PosixError(interp)));
+	}
+	return NULL;
+    }
+
+    channel = NULL;
+
+    switch (FileGetType(handle)) {
+    case FILE_TYPE_SERIAL:
+	/*
+	 * Natively named serial ports "com1-9", "\\\\.\\comXX" are
+	 * already done with the code above.
+	 * Here we handle all other serial port names.
+	 *
+	 * Reopen channel for OVERLAPPED operation. Normally this shouldn't
+	 * fail, because the channel exists.
+	 */
+
+	handle = TclWinSerialOpen(handle, nativeName, accessMode);
+	if (handle == INVALID_HANDLE_VALUE) {
+	    TclWinConvertError(GetLastError());
+	    if (interp != (Tcl_Interp *) NULL) {
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"couldn't reopen serial \"%s\": %s",
+			TclGetString(pathPtr), Tcl_PosixError(interp)));
+	    }
+	    return NULL;
+	}
+	channel = TclWinOpenSerialChannel(handle, channelName,
+		channelPermissions);
+	break;
+    case FILE_TYPE_CONSOLE:
+	channel = TclWinOpenConsoleChannel(handle, channelName,
+		channelPermissions);
+	break;
+    case FILE_TYPE_PIPE:
+	if (channelPermissions & TCL_READABLE) {
+	    readFile = TclWinMakeFile(handle);
+	}
+	if (channelPermissions & TCL_WRITABLE) {
+	    writeFile = TclWinMakeFile(handle);
+	}
+	channel = TclpCreateCommandChannel(readFile, writeFile, NULL, 0, NULL);
+	break;
+    case FILE_TYPE_CHAR:
+    case FILE_TYPE_DISK:
+    case FILE_TYPE_UNKNOWN:
+	channel = TclWinOpenFileChannel(handle, channelName,
+		channelPermissions, (mode & O_APPEND) ? FILE_APPEND : 0);
+	break;
+
+    default:
+	/*
+	 * The handle is of an unknown type, probably /dev/nul equivalent or
+	 * possibly a closed handle.
+	 */
+
+	channel = NULL;
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"couldn't open \"%s\": bad file type",
+		TclGetString(pathPtr)));
+	Tcl_SetErrorCode(interp, "TCL", "VALUE", "CHANNEL", "BAD_TYPE",
+		NULL);
+	break;
+    }
+
+    return channel;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_MakeFileChannel --
+ *
+ *	Creates a Tcl_Channel from an existing platform specific file handle.
+ *
+ * Results:
+ *	The Tcl_Channel created around the preexisting file.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Channel
+Tcl_MakeFileChannel(
+    ClientData rawHandle,	/* OS level handle */
+    int mode)			/* ORed combination of TCL_READABLE and
+				 * TCL_WRITABLE to indicate file mode. */
+{
+#if defined(HAVE_NO_SEH) && !defined(_WIN64)
+    TCLEXCEPTION_REGISTRATION registration;
+#endif
+    char channelName[16 + TCL_INTEGER_SPACE];
+    Tcl_Channel channel = NULL;
+    HANDLE handle = (HANDLE) rawHandle;
+    HANDLE dupedHandle;
+    TclFile readFile = NULL, writeFile = NULL;
+    BOOL result;
+
+    if (mode == 0) {
+	return NULL;
+    }
+
+    switch (FileGetType(handle)) {
+    case FILE_TYPE_SERIAL:
+	channel = TclWinOpenSerialChannel(handle, channelName, mode);
+	break;
+    case FILE_TYPE_CONSOLE:
+	channel = TclWinOpenConsoleChannel(handle, channelName, mode);
+	break;
+    case FILE_TYPE_PIPE:
+	if (mode & TCL_READABLE) {
+	    readFile = TclWinMakeFile(handle);
+	}
+	if (mode & TCL_WRITABLE) {
+	    writeFile = TclWinMakeFile(handle);
+	}
+	channel = TclpCreateCommandChannel(readFile, writeFile, NULL, 0, NULL);
+	break;
+
+    case FILE_TYPE_DISK:
+    case FILE_TYPE_CHAR:
+	channel = TclWinOpenFileChannel(handle, channelName, mode, 0);
+	break;
+
+    case FILE_TYPE_UNKNOWN:
+    default:
+	/*
+	 * The handle is of an unknown type. Test the validity of this OS
+	 * handle by duplicating it, then closing the dupe. The Win32 API
+	 * doesn't provide an IsValidHandle() function, so we have to emulate
+	 * it here. This test will not work on a console handle reliably,
+	 * which is why we can't test every handle that comes into this
+	 * function in this way.
+	 */
+
+	result = DuplicateHandle(GetCurrentProcess(), handle,
+		GetCurrentProcess(), &dupedHandle, 0, FALSE,
+		DUPLICATE_SAME_ACCESS);
+
+	if (result == 0) {
+	    /*
+	     * Unable to make a duplicate. It's definately invalid at this
+	     * point.
+	     */
+
+	    return NULL;
+	}
+
+	/*
+	 * Use structured exception handling (Win32 SEH) to protect the close
+	 * of this duped handle which might throw EXCEPTION_INVALID_HANDLE.
+	 */
+
+	result = 0;
+#if defined(HAVE_NO_SEH) && !defined(_WIN64)
+	/*
+	 * Don't have SEH available, do things the hard way. Note that this
+	 * needs to be one block of asm, to avoid stack imbalance; also, it is
+	 * illegal for one asm block to contain a jump to another.
+	 */
+
+	__asm__ __volatile__ (
+
+	    /*
+	     * Pick up parameters before messing with the stack
+	     */
+
+	    "movl       %[dupedHandle], %%ebx"          "\n\t"
+
+	    /*
+	     * Construct an TCLEXCEPTION_REGISTRATION to protect the call to
+	     * CloseHandle.
+	     */
+
+	    "leal       %[registration], %%edx"         "\n\t"
+	    "movl       %%fs:0,         %%eax"          "\n\t"
+	    "movl       %%eax,          0x0(%%edx)"     "\n\t" /* link */
+	    "leal       1f,             %%eax"          "\n\t"
+	    "movl       %%eax,          0x4(%%edx)"     "\n\t" /* handler */
+	    "movl       %%ebp,          0x8(%%edx)"     "\n\t" /* ebp */
+	    "movl       %%esp,          0xc(%%edx)"     "\n\t" /* esp */
+	    "movl       $0,             0x10(%%edx)"    "\n\t" /* status */
+
+	    /*
+	     * Link the TCLEXCEPTION_REGISTRATION on the chain.
+	     */
+
+	    "movl       %%edx,          %%fs:0"         "\n\t"
+
+	    /*
+	     * Call CloseHandle(dupedHandle).
+	     */
+
+	    "pushl      %%ebx"                          "\n\t"
+	    "call       _CloseHandle@4"                 "\n\t"
+
+	    /*
+	     * Come here on normal exit. Recover the TCLEXCEPTION_REGISTRATION
+	     * and put a TRUE status return into it.
+	     */
+
+	    "movl       %%fs:0,         %%edx"          "\n\t"
+	    "movl	$1,		%%eax"		"\n\t"
+	    "movl       %%eax,          0x10(%%edx)"    "\n\t"
+	    "jmp        2f"                             "\n"
+
+	    /*
+	     * Come here on an exception. Recover the TCLEXCEPTION_REGISTRATION
+	     */
+
+	    "1:"                                        "\t"
+	    "movl       %%fs:0,         %%edx"          "\n\t"
+	    "movl       0x8(%%edx),     %%edx"          "\n\t"
+
+	    /*
+	     * Come here however we exited. Restore context from the
+	     * TCLEXCEPTION_REGISTRATION in case the stack is unbalanced.
+	     */
+
+	    "2:"                                        "\t"
+	    "movl       0xc(%%edx),     %%esp"          "\n\t"
+	    "movl       0x8(%%edx),     %%ebp"          "\n\t"
+	    "movl       0x0(%%edx),     %%eax"          "\n\t"
+	    "movl       %%eax,          %%fs:0"         "\n\t"
+
+	    :
+	    /* No outputs */
+	    :
+	    [registration]  "m"     (registration),
+	    [dupedHandle]   "m"	    (dupedHandle)
+	    :
+	    "%eax", "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory"
+	    );
+	result = registration.status;
+#else
+#ifndef HAVE_NO_SEH
+	__try {
+#endif
+	    CloseHandle(dupedHandle);
+	    result = 1;
+#ifndef HAVE_NO_SEH
+	} __except (EXCEPTION_EXECUTE_HANDLER) {}
+#endif
+#endif
+	if (result == FALSE) {
+	    return NULL;
+	}
+
+	/*
+	 * Fall through, the handle is valid.
+	 *
+	 * Create the undefined channel, anyways, because we know the handle
+	 * is valid to something.
+	 */
+
+	channel = TclWinOpenFileChannel(handle, channelName, mode, 0);
+    }
+
+    return channel;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpGetDefaultStdChannel --
+ *
+ *	Constructs a channel for the specified standard OS handle.
+ *
+ * Results:
+ *	Returns the specified default standard channel, or NULL.
+ *
+ * Side effects:
+ *	May cause the creation of a standard channel and the underlying file.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Channel
+TclpGetDefaultStdChannel(
+    int type)			/* One of TCL_STDIN, TCL_STDOUT, or
+				 * TCL_STDERR. */
+{
+    Tcl_Channel channel;
+    HANDLE handle;
+    int mode = -1;
+    const char *bufMode = NULL;
+    DWORD handleId = (DWORD) -1;
+				/* Standard handle to retrieve. */
+
+    switch (type) {
+    case TCL_STDIN:
+	handleId = STD_INPUT_HANDLE;
+	mode = TCL_READABLE;
+	bufMode = "line";
+	break;
+    case TCL_STDOUT:
+	handleId = STD_OUTPUT_HANDLE;
+	mode = TCL_WRITABLE;
+	bufMode = "line";
+	break;
+    case TCL_STDERR:
+	handleId = STD_ERROR_HANDLE;
+	mode = TCL_WRITABLE;
+	bufMode = "none";
+	break;
+    default:
+	Tcl_Panic("TclGetDefaultStdChannel: Unexpected channel type");
+	break;
+    }
+
+    handle = GetStdHandle(handleId);
+
+    /*
+     * Note that we need to check for 0 because Windows may return 0 if this
+     * is not a console mode application, even though this is not a valid
+     * handle.
+     */
+
+    if ((handle == INVALID_HANDLE_VALUE) || (handle == 0)) {
+	return (Tcl_Channel) NULL;
+    }
+
+    channel = Tcl_MakeFileChannel(handle, mode);
+
+    if (channel == NULL) {
+	return (Tcl_Channel) NULL;
+    }
+
+    /*
+     * Set up the normal channel options for stdio handles.
+     */
+
+    if (Tcl_SetChannelOption(NULL,channel,"-translation","auto")!=TCL_OK ||
+	    Tcl_SetChannelOption(NULL,channel,"-eofchar","\032 {}")!=TCL_OK ||
+	    Tcl_SetChannelOption(NULL,channel,"-buffering",bufMode)!=TCL_OK) {
+	Tcl_Close(NULL, channel);
+	return (Tcl_Channel) NULL;
+    }
+    return channel;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclWinOpenFileChannel --
+ *
+ *	Constructs a File channel for the specified standard OS handle. This
+ *	is a helper function to break up the construction of channels into
+ *	File, Console, or Serial.
+ *
+ * Results:
+ *	Returns the new channel, or NULL.
+ *
+ * Side effects:
+ *	May open the channel and may cause creation of a file on the file
+ *	system.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Channel
+TclWinOpenFileChannel(
+    HANDLE handle,		/* Win32 HANDLE to swallow */
+    char *channelName,		/* Buffer to receive channel name */
+    int permissions,		/* OR'ed combination of TCL_READABLE,
+				 * TCL_WRITABLE, or TCL_EXCEPTION, indicating
+				 * which operations are valid on the file. */
+    int appendMode)		/* OR'ed combination of bits indicating what
+				 * additional configuration of the channel is
+				 * present. */
+{
+    FileInfo *infoPtr;
+    ThreadSpecificData *tsdPtr = FileInit();
+
+    /*
+     * See if a channel with this handle already exists.
+     */
+
+    for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL;
+	    infoPtr = infoPtr->nextPtr) {
+	if (infoPtr->handle == (HANDLE) handle) {
+	    return (permissions==infoPtr->validMask) ? infoPtr->channel : NULL;
+	}
+    }
+
+    infoPtr = ckalloc(sizeof(FileInfo));
+
+    /*
+     * TIP #218. Removed the code inserting the new structure into the global
+     * list. This is now handled in the thread action callbacks, and only
+     * there.
+     */
+
+    infoPtr->nextPtr = NULL;
+    infoPtr->validMask = permissions;
+    infoPtr->watchMask = 0;
+    infoPtr->flags = appendMode;
+    infoPtr->handle = handle;
+    infoPtr->dirty = 0;
+    sprintf(channelName, "file%" TCL_I_MODIFIER "x", (size_t) infoPtr);
+
+    infoPtr->channel = Tcl_CreateChannel(&fileChannelType, channelName,
+	    infoPtr, permissions);
+
+    /*
+     * Files have default translation of AUTO and ^Z eof char, which means
+     * that a ^Z will be accepted as EOF when reading.
+     */
+
+    Tcl_SetChannelOption(NULL, infoPtr->channel, "-translation", "auto");
+    Tcl_SetChannelOption(NULL, infoPtr->channel, "-eofchar", "\032 {}");
+
+    return infoPtr->channel;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclWinFlushDirtyChannels --
+ *
+ *	Flush all dirty channels to disk, so that requesting the size of any
+ *	file returns the correct value.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Information is actually written to disk now, rather than later. Don't
+ *	call this too often, or there will be a performance hit (i.e. only
+ *	call when we need to ask for the size of a file).
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclWinFlushDirtyChannels(void)
+{
+    FileInfo *infoPtr;
+    ThreadSpecificData *tsdPtr = FileInit();
+
+    /*
+     * Flush all channels which are dirty, i.e. may have data pending in the
+     * OS.
+     */
+
+    for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL;
+	    infoPtr = infoPtr->nextPtr) {
+	if (infoPtr->dirty) {
+	    FlushFileBuffers(infoPtr->handle);
+	    infoPtr->dirty = 0;
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileThreadActionProc --
+ *
+ *	Insert or remove any thread local refs to this channel.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Changes thread local list of valid channels.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+FileThreadActionProc(
+    ClientData instanceData,
+    int action)
+{
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+    FileInfo *infoPtr = instanceData;
+
+    if (action == TCL_CHANNEL_THREAD_INSERT) {
+	infoPtr->nextPtr = tsdPtr->firstFilePtr;
+	tsdPtr->firstFilePtr = infoPtr;
+    } else {
+	FileInfo **nextPtrPtr;
+	int removed = 0;
+
+	for (nextPtrPtr = &(tsdPtr->firstFilePtr); (*nextPtrPtr) != NULL;
+		nextPtrPtr = &((*nextPtrPtr)->nextPtr)) {
+	    if ((*nextPtrPtr) == infoPtr) {
+		(*nextPtrPtr) = infoPtr->nextPtr;
+		removed = 1;
+		break;
+	    }
+	}
+
+	/*
+	 * This could happen if the channel was created in one thread and then
+	 * moved to another without updating the thread local data in each
+	 * thread.
+	 */
+
+	if (!removed) {
+	    Tcl_Panic("file info ptr not on thread channel list");
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileGetType --
+ *
+ *	Given a file handle, return its type
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+DWORD
+FileGetType(
+    HANDLE handle)		/* Opened file handle */
+{
+    DWORD type;
+
+    type = GetFileType(handle);
+
+    /*
+     * If the file is a character device, we need to try to figure out whether
+     * it is a serial port, a console, or something else. We test for the
+     * console case first because this is more common.
+     */
+
+    if ((type == FILE_TYPE_CHAR)
+	    || ((type == FILE_TYPE_UNKNOWN) && !GetLastError())) {
+	DWORD consoleParams;
+
+	if (GetConsoleMode(handle, &consoleParams)) {
+	    type = FILE_TYPE_CONSOLE;
+	} else {
+	    DCB dcb;
+
+	    dcb.DCBlength = sizeof(DCB);
+	    if (GetCommState(handle, &dcb)) {
+		type = FILE_TYPE_SERIAL;
+	    }
+	}
+    }
+
+    return type;
+}
+
+ /*
+ *----------------------------------------------------------------------
+ *
+ * NativeIsComPort --
+ *
+ *	Determines if a path refers to a Windows serial port.
+ *	A simple and efficient solution is to use a "name hint" to detect
+ *      COM ports by their filename instead of resorting to a syscall
+ *	to detect serialness after the fact.
+ *	The following patterns cover common serial port names:
+ *	    COM[1-9]
+ *	    \\.\COM[0-9]+
+ *
+ * Results:
+ *	1 = serial port, 0 = not.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+NativeIsComPort(
+    const TCHAR *nativePath)	/* Path of file to access, native encoding. */
+{
+    const WCHAR *p = (const WCHAR *) nativePath;
+    int i, len = wcslen(p);
+
+    /*
+     * 1. Look for com[1-9]:?
+     */
+
+    if ( (len == 4) && (_wcsnicmp(p, L"com", 3) == 0) ) {
+	/*
+	* The 4th character must be a digit 1..9
+	*/
+
+	if ( (p[3] < L'1') || (p[3] > L'9') ) {
+	    return 0;
+	}
+	return 1;
+    }
+
+    /*
+     * 2. Look for \\.\com[0-9]+
+     */
+
+    if ((len >= 8) && (_wcsnicmp(p, L"\\\\.\\com", 7) == 0)) {
+	/*
+	* Charaters 8..end must be a digits 0..9
+	*/
+
+	for ( i=7; i<len; i++ ) {
+	    if ( (p[i] < '0') || (p[i] > '9') ) {
+		return 0;
+	    }
+	}
+	return 1;
+    }
+    return 0;
+}
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */