Re: How to know a program was compiled with ALWNULL(*YES)

On 01-Apr-2015 15:25 -0500, Charles Wilt wrote:

Saw the subject question on stack overflow..
<http://stackoverflow.com/q/29399592/2933177?sem=2>

<<SNIP>>

I suspect it's not available anywhere. <<SNIP>>

What RPG believes should have been established for the attribute of allowing NULL values on an ODP is revealed in an RPG DUMP, ever since the file is successfully opened. Thus if the program can be forced to experience an I/O error for which a D=Dump can be requested in response to the RPG default handler taking over control, then finding out that information is as easy as reviewing the "Null Capable Field File" in the "OPEN FEEDBACK" for the ODP of actual file.mbr that was opened.

And a sure-fire way to make any read fail is to add a bogus read trigger program that does nothing but issue an error; or easiest, just name an existing program that does not accept the required two parameters, such as QCMD. Probably best to create a dummy file to which the trigger is added, and then issue an override with that database file named as the TOFILE, so the program refers to that overridden-to file instead. When the bogus file is done being used to find out the AlwNull setting [as applied by RPG run-time, which one might expect typically would reflect the compile-time setting; at least for externally-described file references], then just delete the file so both the *FILE and the trigger go away.