Re: Ending a program from within a procedure -- RPG400-L


On 26/07/2005, at 8:26 AM, Paul Morgan wrote:

All just because the exception handling model on the 400 (escapemessages)
doesn't allow for automatic propagation up the call stack.

Not quite true. In an ILE environment exceptions are propagated up thecall stack until a control boundary is reached.

You either
handle it at the target of the escape message or the system takes overwithsome default handling. Because of that model your subroutine has tohaveknowledge of the top level entry point. That's unnecessary cohesionbetween
the subroutine and the 'top level' point.

Not true. You can send to *PGMBDY plus 1 relative invocation level andknow that the message will be sent to the caller of the programcontaining your sub-routine or procedure regardless of what program isthe caller.

Better would be the subroutine throwing an exception to it's caller(where'sthe RPG THROW opcode?). Let the caller decide to handle the exceptionor if
it's ignored it gets automatically bubbled up to it's own caller.

That's exactly what happens with ILE procedures but it stops at the thefirst control boundary. Easy solution is to have each program thatstarts a control boundary catch all exceptions. They can either handlethem or throw them on. Eventually someone will either handle it or thesystem default handler will deal with it.

Eventually it would then reach your 'top level' point that wouldhandle theexception. If it's not handled it would reach the top of the callstack and
get some default handling like ending the job or breaking on QSYSOPR.

Sounds like the above description. Easy enough to do with existingfunctions.


Regards,
Simon Coulter.
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