$hObject = 0;
$result = &testmain::DoAttach( 123, 0x1234, $hObject);

##</code><code>##

long
dsmFSAttach(PID,service,hFS)
    unsigned short     PID
    unsigned short     service
    unsigned long   *   hFS

    OUTPUT:
    hFS
    RETVAL

##</code><code>##

long DoAttach(unsigned short PID, 
             unsigned short service, 
             unsigned long *hFS)
{
    *hFS = ReturnFromSomeFunc(...)
    return foo;
}