seqnet_connection

	status.i4.v = seqnet_connection(req_callback.f.v)

	Initialize application's connection for Sequencer communication.
	This function must be called in the program's initialization and
	before using any other SEQNET functions.

	SEQNET requests may be retrieved in one of two ways: specify a
	callback function here, or call seqnet_request_check periodically.
	See seqnet_an_introduction for more details.

	req_callback	function to be called upon receipt of any
			SEQNET requests (type is 'seqnet_request_cb_t')
			(It is called as follows:
			 user_request(int id, int command, int synch,
				      unsigned short length, void *message))
			(Pass a value of NULL if no callback is desired.)

	This function returns ACNET status values as follows:

	OK			success
	CBS_DUBREQ		already connected
	CBS_NOTENB		failed to establish callback (if requested)
	ACNET_xxx		failed

	This function requires the following include files:

	seqnet_h, acnet_errors_h

	Related functions:

	seqnet_request_check, seqnet_reply_update, seqnet_reply_message,
	seqnet_disconnect, seqnet_started, seqnet_send_status_message,
	seqnet_requester_info_c, seqnet_an_introduction

	C/C++ usage:

	int	status;
	void	req_callback(int request_id, int request_command,
			     int request_synch, unsigned short request_length,
			     void *request_message);

	status = seqnet_connection(req_callback);