file_id

IN:

File identifier returned by Hopen

	Purpose	Returns a reference number that can be used with any tag to produce a unique tag /reference number pair.
	Return value	Returns the reference number if successful and 0 otherwise.
	Description	Successive calls to Hnewref will generate reference number values that increase by one each time until the highest possible reference number has been returned. At this point, additional calls to Hnewref will return an increasing sequence of unused reference number values starting from 1.