Re: IBM z/OS compatibility issues - environment variables

[Bruno Haible]

Hi Daniel,

> ENVIRONMENT VARIABLES
> 
> One annoyance on this platform is that the default behavior of things
> can sometimes be weirdly different from other platforms, in a way which
> breaks programs expecting normal Unix/POSIX behavior. Unfortunately,
> IBM's response to this is often not "Let us fix that so it works like
> other Unix systems," but "That's too bad. We can't change the default
> behavior because mumblemumble, but we can provide an environment
> variable that, if set, with cause that thing to behave in the manner
> you expect."
> 
> At present, the only such variable worth mentioning here is
> _EDC_SIG_DFLT, which when set to 1, causes certain default signal
> handlers *not* to print out messages:
> 
>     
> https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.cbcpx01/edc_sig_dflt.htm
> 
> This is something that should at least be set in the gnulib test
> environment so that test-sigpipe.sh doesn't break, but may be worth
> adding to the library itself so that programs can continue to expect
> "normal" signal semantics.
> 
> (There are other environment variables documented at the link above that
> may be of interest, but I have not found any additional ones to be
> necessary to fix issues in gnulib's test suite.)

So, the gnulib tests for the math functions and *printf work fine without
_EDC_SUSV3? And the ones for *printf work fine without _EDC_C99_NAN?

I think many programs that are built with gnulib invoke other programs;
therefore it is risky to add setenv calls for such environment variables
to gnulib itself. But we can do so
  - in the documentation,
  - in particular tests. You mentioned test-sigpipe.sh; do you have a
    list of tests which fail by default and succeed with one of these
    environment variables.

Bruno