Sticking diagnostic information (up to 16k) where calling program can get it?

I've currently got a situation where program A calls program B (both ILE RPG).

If program B gets an error, it generates up to 16k of diagnostics before returning a "failed" return code to program A. It currently uses a call to "puts()" from the ILE C runtime to send those diagnostics to STDOUT (either the "red function key" screen for interactive jobs, or a job-global spool file for server jobs.

If Program A gets a "failed" return code from program B, it then adds a few lines of its own to STDOUT, again with a call to the c "puts()," which then seemlessly integrate with the diagnostics from program B. Looking at either the "red function key" screen or the spool file, you can't tell that the contents were written by two different programs.

BUT NOW, I've had a request to put that diagnostic information in other places, including possibly emailing them (without the need to have MAILTOOL, MMAIL, or anything else installed).

Dispatching the complete diagnostics, when program A has them, isn't the problem. I'm currently trying to figure out a nice, easy-to-implement, place for program B to stick its diagnostics (up to 16k) where program A can get at them (without adding another parameter to the call), and my sleep-deprived brain (Academy of Ancient Music at Disney Hall, last night) doesn't want to cooperate.

I can of course fall back on creating a USRSPC, but I was hoping for something simpler.

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JHHL