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To: xemacs-beta@xemacs.org
Subject: Re: Build Success 20.3b7 "Oslo" - with one problem
Reply-To: jaeger@informatik.uni-kl.de
References: <m0wduFc-0001oEC@arthur.rhein-neckar.de> <199706180816.BAA02672@xemacs.eng.sun.com> <m2yb87443f.fsf@altair.xemacs.org>
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From: Andreas Jaeger <aj@arthur.rhein-neckar.de>
Date: 19 Jun 1997 08:15:10 +0200
In-Reply-To: Steven L Baur's message of "18 Jun 1997 21:19:16 -0700"
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>>>>> Steven L Baur writes:

sb> Martin Buchholz <mrb@Eng.Sun.COM> writes:
>> If something like compface really needs _BSD_SOURCE, we can always do
>> something like:

>> #undef _BSD_SOURCE
>> #define _BSD_SOURCE
>> #include <compface.h>
>> #undef _BSD_SOURCE

>> I really think we should try as hard as possible to avoid BSDisms.

sb> The problem is one of binary compatibility, it has nothing to do with
sb> source.  For better or for worse, the presence or non-presence of
sb> _BSD_SOURCE changes the size of the jmp_buf structure.  Since the
sb> standard XFree86 X11 binaries come compiled with -D_BSD_SOURCE as a
sb> default, we're kind of stuck between a rock and a hard place.
With glibc2 there's no problem - and even with libc5.4.23, there are
different sizes depending on the macro __SVR4_I386_ABI_L1__ and I
don't know where it's defined. Therefore I can't directly see that
there's a difference if _BSD_SOURCE is defined.

As explained already in my email with the subject "XEmacs 20.3b6+:
Defining _BSD_SOURCE is not ok": It's wrong to solely use
-D_BSD_SOURCE since we don't favor BSD, we just like to use some
features. XFree 3.3 is compiled with -D_BSD_SOURCE -D_POSIX_SOURCE
-D_SVID_SOURCE and this is completly different to only defining
_BSD_SOURCE (see <features.h>) [1].

Btw. since the definition in the last two betas of _BSD_SOURCE was
totally useless (defined at the wrong place), following your argument
everybody should have problems under Linux because of jmp_buf - but
nobody AFAIK reported a problem so far.

Andreas

[1] libc5 always favors BSD if _BSD_SOURCE is set, but glibc
doesn't. Defining all three flags is AFAIK the only portable solution
to support both libc5 and glibc2.

-- 
 Andreas Jaeger   aj@arthur.rhein-neckar.de    jaeger@informatik.uni-kl.de
  for pgp-key finger ajaeger@alma.student.uni-kl.de
    http://www.student.uni-kl.de/~ajaeger/

