Vgetid/vfgid

int32 Vgetid(int32 file_id, int32 vgroup_ref)

file_id	IN:	File identifier returned by Hopen
vgroup_ref	IN:	Reference number of the previous vgroup

Purpose	Searches through the HDF file and returns the reference number of the next vgroup following the vgroup that has the reference number vgroup_ref. It is used to sequentially search the file for vgroups.
Return value	Returns the reference number of the next vdata if successful and FAIL (or -1) otherwise.
Description	To initiate a search, call this routine with a vgroup_ref value of -1. This will return the reference number of the first vgroup in the file. Searching past the last vgroup in the file will return an error.
Example	This sample code prints out the reference numbers of all vgroups in the HDF file.


     int32 file_id; /* id of an opened HDF file */
     int32 vgroup_ref;

     file_id = Hopen("myfile.hdf",DFACC_READ,0);
     Vstart(file_id);
     vgroup_ref = -1;
     while (1) {
       vgroup_ref = Vgetid(file_id, vgroup_ref);
       if (vgroup_ref == -1) break;
       printf("found vgroup with id %d\n", vgroup_ref);
     }

     Vend(file_id);
     Hclose(file_id); 


 FORTRAN

 integer function vfgid(file_id, vgroup_ref)


 

 integer file_id, vgroup_ref

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HDF User's Reference Manual, Draft 06/09/97, NCSA HDF Development Group.

FORTRAN	integer function vfgid(file_id, vgroup_ref)
	integer file_id, vgroup_ref