* Access to the list of threads and to the thread send results is guarded by
 * this mutex.
 */

TCL_DECLARE_MUTEX(threadMutex)

static int		ThreadObjCmd(void *clientData,
			    Tcl_Interp *interp, size_t objc,
			    Tcl_Obj *const objv[]);
static int		ThreadCreate(Tcl_Interp *interp, const char *script,
			    int joinable);
static int		ThreadList(Tcl_Interp *interp);
static int		ThreadSend(Tcl_Interp *interp, Tcl_ThreadId id,
			    const char *script, int wait);
static int		ThreadCancel(Tcl_Interp *interp, Tcl_ThreadId id,

 *----------------------------------------------------------------------
 */

static int
ThreadObjCmd(
    TCL_UNUSED(void *),
    Tcl_Interp *interp,		/* Current interpreter. */
    size_t objc,			/* Number of arguments. */
    Tcl_Obj *const objv[])	/* Argument objects. */
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    static const char *const threadOptions[] = {
	"cancel", "create", "event", "exit", "id",
	"join", "names", "send", "wait", "errorproc",
	NULL

	Tcl_MutexUnlock(&threadMutex);
    }

    switch (option) {
    case THREAD_CANCEL: {
	Tcl_WideInt id;
	const char *result;
	int flags;
	size_t arg;

	if ((objc < 3) || (objc > 5)) {
	    Tcl_WrongNumArgs(interp, 2, objv, "?-unwind? id ?result?");
	    return TCL_ERROR;
	}
	flags = 0;
	arg = 2;