RE: monitor for exception by message id

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Simon Coulter
Sent: Thursday, March 06, 2003 8:52 AM
To: RPG programming on the AS400 / iSeries
Subject: RE: monitor for exception by message id

>>In my own stuff, I don't actually throw escape messages to the caller.
>>Rather, I set a return code that the caller needs to inspect.  I stick my
>>return codes in a /COPY member and refer to them via mnemonics rather than
>>by number.  I'm not sure if this helps or not...

>Return codes have their place but in my view the exception model is far
>superior. That is because a return code can be ignored by the caller but an
>exception cannot. Unix is a prime example of an environment where return
>codes are used and frequently never checked because "that error will never
>happen" and "error handling code makes the program slow" and other lame

I dont disagree, but would add that a return code argument can satisfy some
"ignore the return code" concerns.  If the return code is an argument:
   DoSomething( vlu1: vlu2: %addr(RtnCode) ) ;

then *Null can be passed to the proc when the caller wants a hard *escape
message halt in the event of an error.
   DoSomething( vlu1: vlu2: *Null ) ;

Steve