Example 14-1: Creating a USEROPEN Routine
  %TITLE "Example USEROPEN"
  %SBTTL "Useropen Routine to obtain RAB address"
  %IDENT "Version 1.1"
  FUNCTION LONG Get_rab_address ( Fabdef User_fab, Rabdef User_rab, LONG Channel )
  !++
  ! FUNCTIONAL DESCRIPTION:
  !
  ! Save the address of the RMS Record Access Block allocated by the caller
  ! in a global symbol. Open the file and return the status from RMS.
  !
  ! FORMAL PARAMETERS (Standard for all BASIC USEROPEN procedures)
  !
  ! User_fab Address of RMS File Access Block
  ! User_rab Address of RMS Record Access Block
  ! Channel Logical Unit assigned to file by caller.
  !
  ! RETURN VALUE: RMS Status value
  !
  ! GLOBAL COMMON USAGE
  !
  ! RAB_ptr Single longword PSECT used to pass RAB address to caller.
  !
  !--
        OPTION INACTIVE = SETUP, &
                CONSTANT TYPE = INTEGER, &
                TYPE = EXPLICIT
        %NOLIST
        %INCLUDE "$FABDEF" %FROM %LIBRARY "SYS$LIBRARY:BASIC$STARLET"
        %INCLUDE "$RABDEF" %FROM %LIBRARY "SYS$LIBRARY:BASIC$STARLET"
        %INCLUDE "$RMSDEF" %FROM %LIBRARY "SYS$LIBRARY:BASIC$STARLET"
        %INCLUDE "STARLET" %FROM %LIBRARY "SYS$LIBRARY:BASIC$STARLET"
        %LIST
        !+
        ! Common area used to pass RAB address to caller.
        !-
        COMMON (RAB_ptr) LONG rab_address
        DECLARE LONG Rms_status
        !+
        ! Save RAB address in global symbol known to caller.
        ! Perform standard RMS open sequence
        !-
        Rab_address = LOC(User_rab::rab$b_bid)
        Rms_status = Sys$open( User_fab )
        IF Rms_status AND Rms$_normal
        THEN
              Rms_status = Sys$connect( User_rab )
        END IF
  END FUNCTION Rms_status