Re: IBM z/OS compatibility issues

[Daniel Richard G.]

On Sun, 2019 Nov 17 18:21-05:00, Bruno Haible wrote:
> Hi Daniel,
> 
> > The C99 mode (-qlanglvl=extc99) works without issue. That's what I've
> > been using for all my testing.
> 
> Do you have a set of configure settings that you would recommend on z/OS?
> So that we can add this info to the Gnow-How wiki [1]...

There are quite a few, unfortunately. Before getting into them, however,
there is something I am not clear on:

How should platform-specific compiler flags, feature-test macros, etc.
be split up among the following?

  1. Flags set in Autoconf (common system/compiler checks)

  2. Flags set in Automake ("compile" script)

  3. Flags set in Gnulib's AC_USE_SYSTEM_EXTENSIONS()

  4. Flags set in other Gnulib modules

  5. Flags set by the user in the environment or configure command line
     (obtained from online documentation, discussions, etc.)

z/OS has a number of idiosyncrasies that are not shared even by the
other strange Unix platforms, and putting a lot of weight in bucket #5
seems to me like it will make the system needlessly tricky to navigate
for GNU users unfamiliar with it.

Here are examples of what I currently think should go in each bucket:

  1. -qhaltonmsg=CCN3296, so that missing header files are treated as
     errors, not warnings (thus allowing header checks to return
     meaningful results);

  2. The -qnosearch/-qsearch logic previously described for xlc-wrap,
     so that it is possible for a project to replace an existing
     system header;

  3 or 4. Feature-test macros needed to obtain a recognizable
     pthreads API;

  5. CC=xlc (there are a few usable XLC compiler frontends, and the user
     might prefer one or another for whatever reason)


--Daniel


-- 
Daniel Richard G. || address@hidden
My ASCII-art .sig got a bad case of Times New Roman.