Returns the reference number of a vgroup specified by its class name.
Return value
Returns the reference number of the vgroup if successful and 0 otherwise.
Description
Vfindclass searches the file identified by the parameter file_id for the vgroup with the class name specified by the parameter vgroup_class, and returns the reference number of that vgroup.
If more than one vgroup has the same class name, Vfindclass will return the reference number of the first one.