You are encouraged to write your own message files to use with SIGNAL.  However,
there are a number of useful messages out there already that you may want to
use.  This directory caontains four lists to help you utilize the existing
messages on the system.  These lists apply to the default messages on the
system.  There are also a number of message files in the SYS$MESSAGE directory
that are not covered here.  

ERRCODE.LIS contains a list of success message codes (in hexadecimal, minus the
facility number) that are present on VMS 5.4-1.  Use the file FACILITY.LIS to
find the appropriate facility number and replace "fac#" with that number.  For
example, 

ERRCODE.LIS contains this entry:
        fac#0029  %fac-S-ABORT, abort

FACILITY.LIS contains this entry:
        11E   UTIL

So, "SIGNAL %x11E0029" would give the message "%UTIL-S-ABORT, abort".  To
change the severity, either change the number or use the SEVERITY qualifier. 
e.g.,   %x11E0028 --> %UTIL-W-ABORT, abort
        %x11E0029 --> %UTIL-S-ABORT, abort
        %x11E002A --> %UTIL-E-ABORT, abort
        %x11E002B --> %UTIL-I-ABORT, abort
        %x11E002C --> %UTIL-F-ABORT, abort


The file RMS.LIS contains the RMS message codes.  These are the message codes
that use the RMS_STATUS qualifier.  My experience has been that the codes that
start with "0001C" require the NORMS_STATUS qualifier to work properly.

The last file is SYSTEM_EXCEPTION.LIS.  These are the only system messages
(facility number 000)  that will accept FAO parameters.  If you pass FAO
parameters to any of the other system messages you will get unexpected results.