Re: Odd CALLPRC behavior when using RPG indicator with RTNVAL

On 27/03/2009, at 7:56 AM, David Gibbs wrote:

Got an answer from IBM ... not what I was hoping for:

"6.1 is working as designed. The pre-V5R1 recommendation in the RPG
Programmer's Reference to declare a 2-byte character variable to receive a
1-byte return value was mistaken. It relied on unarchitected, then- current,
implementation details.

The change in behavior can occur only under very limited circumstances.
Among the necessary conditions are interlanguage procedure calls where the
calling and called procedures disagree about the size of the returned
value. It is likely that only the very specific scenario reported will
affect any customers.

Because an IBM recommendation prompted this issue, we are working on
suitable means to help customers determine whether they might be affected.
We will also be updating the 6.1 Memo To Users and will describe this
scenario in the Memo To Users for the next release.

Thank you for finding and reporting the mistaken reference material."

I would reject that answer as unacceptable. A better solution would be to provide an option on the DCLPRCOPT CL command that changes the way the CL program handles these return values. That way the "fix" is under the control of the programmer who can decide whether the CL program should operate with C conventions or those used by every other OS/400 programming language (except Java but that can't really be used from CL). Such a fix should be PTFed back to 540 to allow vendors and customers to migrate code PRIOR to upgrading to 610.

Regards,
Simon Coulter.
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