Returns the total number of attributes of a vdata and of its fields.
Return value
Returns the total number of attributes if successful and FAIL (or -1) otherwise.
Description
VSnattrs returns the total number of attributes of the vdata, vdata_id, and of its fields.
VSnattrs is different from the VSfnattrs routine, which returns the number of attributes of a specified vdata or of a field contained in a specified vdata.