/*
 * Return the thread-specific Tcl interpreter, creating it if needed
 */
static Tcl_Interp *appfs_TclInterp(void) {
	Tcl_Interp *interp;
	int pthread_ret;
	static __thread int thread_interp_reset_key = 0;
	int global_interp_reset_key;

	global_interp_reset_key = __sync_fetch_and_add(&interp_reset_key, 0);

	interp = pthread_getspecific(interpKey);
	if (interp != NULL && thread_interp_reset_key != global_interp_reset_key) {
		APPFS_DEBUG("Terminating old interpreter and restarting due to reset request.");

		Tcl_DeleteInterp(interp);

		interp = NULL;

		thread_interp_reset_key = global_interp_reset_key;
	}

	if (interp == NULL) {
		interp = appfs_create_TclInterp(NULL);

		if (interp == NULL) {
			return(NULL);