Returns

   OpenVMS usage:cond_value
   type:         longword (unsigned)
   access:       write only
   mechanism:    by value

   Longword condition value. In most cases, the routine returns
   either the same signal passed to it in the condition value
   argument, or the return value of LIB$SIGNAL. If the routine
   fails, it signals TPU$_FAILURE and returns control to the caller.