[Python-Dev] Pervasive socket failures on Windows

[Tim Peters]

[Martin v. Löwis]
> For the moment, I have committed Tim's original proposal.

Thank you!  I checked, and that fixed all the test failures I was
seeing on Windows.

> Moving the macro into pyport.h could be done in addition. That
> should be done only if selectmodule is also adjusted; this currently
> tests for _MSC_VER.

It's a nice illustration of why platform-dependent code sprayed across
modules sucks, too.  Why _MSC_VER instead of MS_WINDOWS?  What's the
difference, exactly?  Who knows?

I see that selectmodule.c has this comment near the top:

   Under BeOS, we suffer the same dichotomy as Win32; sockets can be anything
   >= 0.

but there doesn't appear to be any _code_ matching that comment in
that module -- unless on BeOS _MSC_VER is defined.  Beats me whether
it is, but doubt it.

The code in selectmodule when _MSC_VER is _not_ defined complains if a
socket fd is >= FD_SETSIZE _or_ is < 0.  But the new code in
socketmodule on non-Windows boxes is happy with negative fds, saying
"fine" whenever fd < FD_SETSIZE.  Is that right or wrong?

"The answer" isn't so important to me as that this kind of crap always
happens when platform-specific logic ends up getting defined in
multiple modules.  Much better to define macros to hide this junk,
exactly once; pyport.h is the natural place for it.