Re: cygwin -mno-cygwin AC_CHECK_SIZEOF

[Bob Rossi <bob_rossi at cox dot net>]

On Thu, Nov 30, 2006 at 11:57:41PM -0500, Igor Peshansky wrote:
> On Thu, 30 Nov 2006, Eric Blake wrote:
> 
> > According to Bob Rossi on 11/30/2006 7:32 PM:
> >
> > > AC_CHECK_SIZEOF does these two things on cygwin with autoconf 2.60.
> > >   fprintf(f, "%d\n", sizeof($1));
> > > which prints "4\r\n" if the size is 4 and then
> > >   AC_CV_NAME=`cat conftestval`, ...
> > > now cygwin's cat doesn't understand \r\n, so

> > Or experiment with the recent add-on to cygwin's bash, where exporting
> > SHELLOPTS with the cygwin-specific shell option igncr set will tell
> > subsequent /bin/sh invocations to strip \r from command substitution.
> 
> Although this might work.

This is interesting.

bash --version
GNU bash, version 3.2.5(7)-release (i686-pc-cygwin)

$ export SHELLOPTS=$SHELLOPTS:igncr
-bash: SHELLOPTS: readonly variable

Is there anything special I need to do here? I'll google some more ...

> > And the fact that you are now telling configure the truth that you are
> > cross-compiling, even though the cross binaries are executable, may be
> > enough for autoconf to try harder for discovering how AC_CHECK_SIZEOF
> > should behave without tripping up on line endings (and if that is not
> > the case, maybe we should consider patching autoconf to make it happen
> > that way).
> 
> Or have autoconf use some other tool that does not do binary processing
> (e.g., awk or tr) instead of cat, which would enable the text mount
> solution.

I really think this is the current best solution, that is, to modify
autoconf to not use cat. Either that, or simply don't put the \n in the
AC_CHECK_SIZEOF macro. I'm not sure why that is done in the first place.
If
  fprintf(f, "%d\n", sizeof($1));
was changed to
  fprintf(f, "%d", sizeof($1));
I think it would fix the problem.

Well, I downloaded the autoconf sources, but couldn't find the
AC_CHECK_SIZEOF code. I did find it in /usr/share/autoconf, but when I
modify it, the system autoconf behavior doesn't change. Any ideas?

Thanks,
Bob Rossi

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