10	Function integer TPU$CALLUSER ( some_integer% , &
                                        input_string$ , &
                                        return_string$ )
 !++
 ! FACILITY:	 TPU$calluser routine 
 !
 ! ABSTRACT:	 Use the system system to set and show logical names
 !--

20      external integer function lib$sys_trnlog 
        external integer function lib$set_logical 
	external integer function lib$signal
	external integer function lib$sys_getmsg

        external integer constant ss$_normal
	external long    constant ss$_supersede
	external long    constant ss$_bufferovf
	external long    constant ss$_accvio
	external long    constant ss$_ivlogname

	declare  integer code
        declare  integer return_code

        return_string$ = "" 

        ! parse the input string: logname "," parameter 
	! find and extract the logname
	comma_location = pos ( input_string$, ",", 1% )
	if comma_location = 0 then go to all_done end if

	logname$ = seg$( input_string$, 1%, comma_location - 1% )

	! find and extract the parameter_value
	log_parameter$ = seg$( input_string$, comma_location + 1% ,  &
			  len( input_string$) )

	Return_code = lib$set_logical ( logname$ , log_parameter$ )
        
        SELECT Return_code
        CASE SS$_NORMAL    ! everthing is ok
	     Return_code = SS$_normal
        CASE SS$_supersede ! everthing is ok
	     Return_code = SS$_normal
        CASE SS$_bufferovf ! Not good but not going to die either
	     Return_code = SS$_normal
        END SELECT
 

9999	all_done: ! return_string$ is defined 
        TPU$CALLUSER = Return_code
                 
	end function