The HDF_VG_LONE function returns an array containing the IDs of all VGroups in an HDF file that are not contained in another VGroup.
Result = HDF_VG_LONE( FileHandle [, MAXSIZE=value] )
Returns the IDs of lone VGroups or returns -1 if there are no lone VGroups,.
The HDF file handle returned by a previous call to HDF_OPEN.
The maximum number of groups to return (the default is to return all lone VGroups). For example, to return no more than 12 VGroups, use the command:
X = HDF_VG_LONE(fid, MAX=12)
X=HDF_VG_LONE(fid) IF X(0) EQ-1 THEN $ PRINT, "No Lone VGroups" ELSE PRINT, "Lone VGroups:", X