is_open.i4.v = fm_is_open(file_name.i1a.r [,write_access.i4.r]
				  [,access_mode.i4.r] [,num_opens.i4.r])

	This routine will indicate whether or not the requested file is
	open and will optionally return its access modes if it is.

	file_name	Filesharing file name excluding the prefix
			of "rsx$fshare_applicat_" (must be null terminated)
	[write_access]	returned read/write access mode (default is NULL)
			(FMNGR_READ_ACCESS -> read only,
			 FMNGR_WRITE_ACCESS -> write access)
	[access_mode]	returned record access mode (default is NULL)
			(FMNGR_DIRECT -> direct (random by record number),
			 FMNGR_SEQUENTIAL -> sequential,
			 FMNGR_APPEND -> append (sequential),
			 FMNGR_KEYED -> keyed)
	[num_opens]	number of presently open connections to this file
			(default is NULL)

	This function returns status values as follows:

	TRUE			file is open
	FALSE			file is not open

	This function requires the following include files:

	cnsparam_h, cbslib_h

	Related functions:

	fm_open(_c), fm_open_io(_c), fm_open_read(_c), fm_open_write(_c)

	C/C++ usage:

	static const char	file_name[] = "controls_misc:my_file.dat";
	int	is_open;
	int	write_access;
	int	access_mode;
	int	num_opens;

	is_open = fm_is_open(file_name,&write_access,&access_mode,&num_opens);