periodic_callback_init_c (ul_threaded)

	status.i4.v = periodic_callback_init_c(period.u4.v,

	This routine will create a periodic callback.  The period is
	expressed in milliseconds.

	period		requested period in milliseconds
	want_immediate	flag indicating whether or not to call the
			callback function immediately
			(TRUE -> call the function immediately,
			 FALSE -> wait for the period to call the function)
	callback_func	function to be called periodically
			(called as follows:
			 callback_func(handle.i1a.r, period.u4.v,
				       periodic_count.u4.v, clinks.u4.v,
				       nanoseconds.u4.v, func_data.g.v))
	func_data	pointer to user data to be passed to the callback
			function (A value of NULL can be passed for this
			argument if it is not needed.)
	handle		null terminated ASCII handle to be passed as an
			argument to this callback
			(Note: If this argument is not needed, a value of
			 NULL can be passed for it.)
	options		periodic options (not used)

	This function returns ACNET status values as follows:

	OK			success
	CLIB_INVARG		a value of NULL was passed for the
				callback function argument
	CLIB_MEMFAIL		failed in allocating dynamic memory
	CLIB_BUGCHK		error creating periodic thread

	This function requires the following include files:

	ul_threaded_h:threadedlib_h, acnet_errors_h

	Related functions:

	periodic_callback_term_c, timer_callback_request_c

	C/C++ usage:

	char	*handle = (char *) NULL;
	int	status;
	int	want_immediate = FALSE;
	int	callback_id;
	unsigned int	period = PERIOD_VALUE;
	unsigned int	options = 0;
	void	*func_data = (void *) NULL;
	void	callback_func(char const *handle, unsigned int period,
			      unsigned int periodic_count, unsigned int clinks,
			      unsigned int nanoseconds, void *func_data);

	status = periodic_callback_init_c(period,want_immediate,callback_func,