const char *bspos)
{
    if (!bspos) {
	if (current > start) {	/* part before current (special) */
	    Tcl_DStringAppend(dsPtr, start, (int) (current - start));
	}
    } else {
    	if (bspos > start) {	/* part before first backslash */
	if (bspos > start) {	/* part before first backslash */
	    Tcl_DStringAppend(dsPtr, start, (int) (bspos - start));
	}
	while (bspos++ < current) { /* each backslash twice */
	    TclDStringAppendLiteral(dsPtr, "\\\\");
	}
    }
}

     * main quotes, so `\` remains `\`, but important - not at end of part,
     * because results as before the quote, so `%\%\` should be escaped as
     * `"%\%"\\`).
     */

    TclDStringAppendLiteral(dsPtr, "\""); /* opening escape quote-char */
    do {
    	*bspos = NULL;
	*bspos = NULL;
	special++;
	if (*special == '\\') {
	    /*
	     * Bypass backslashes (and mark first backslash position).
	     */

	    special = BuildCmdLineBypassBS(special, bspos);

	infoPtr->readable = CreateEventW(NULL, TRUE, TRUE, NULL);
	infoPtr->readThread = CreateThread(NULL, 256, PipeReaderThread,
	    TclPipeThreadCreateTI(&infoPtr->readTI, infoPtr, infoPtr->readable),
	    0, NULL);
	SetThreadPriority(infoPtr->readThread, THREAD_PRIORITY_HIGHEST);
	infoPtr->validMask |= TCL_READABLE;
    } else {
    	infoPtr->readTI = NULL;
	infoPtr->readTI = NULL;
	infoPtr->readThread = 0;
    }
    if (writeFile != NULL) {
	/*
	 * Start the background writer thread.
	 */

	infoPtr->writable = CreateEventW(NULL, TRUE, TRUE, NULL);
	infoPtr->writeThread = CreateThread(NULL, 256, PipeWriterThread,
	    TclPipeThreadCreateTI(&infoPtr->writeTI, infoPtr, infoPtr->writable),
	    0, NULL);
	SetThreadPriority(infoPtr->writeThread, THREAD_PRIORITY_HIGHEST);
	infoPtr->validMask |= TCL_WRITABLE;
    } else {
    	infoPtr->writeTI = NULL;
    	infoPtr->writeThread = 0;
	infoPtr->writeTI = NULL;
	infoPtr->writeThread = 0;
    }

    /*
     * 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).

    /*
     * End of work, check the owner of the TI structure.
     */

    if (state != PTI_STATE_STOP) {
	*pipeTIPtr = NULL;
    } else {
    	pipeTI->evWakeUp = NULL;
	pipeTI->evWakeUp = NULL;
    }
    if (wakeEvent) {
    	SetEvent(wakeEvent);
	SetEvent(wakeEvent);
    }
    return 0;
}

/*
 *----------------------------------------------------------------------
 *