Bernd, I do not know what control you have over user code that invokes yours, but PL/I has for long supported the use of sysnull rather than null, i.e., '000000000'B4 instead of 'FF000000'B4 as the null, points-nowhere, EOL, pointer value.
Moreover, a PL/I preprocessor procedure that 1) replaces all instances of null in a PL/I source program with instances of sysnull and 2) ensures that any PL/I source program that then contains one or more instances of sysnull also contains one and only one instance of the declaration declare sysnull builtin ; is easy to construct. (I have one that you are welcome to have a copy of.) I am not sure that I fully understand your users' problems, but null should long since have been eliminated from their source programs, and a compile-time solution is much to be preferred to an execution-time one. John Gilmore, Ashland, MA 01721 - USA ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
