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Date: Thu, 30 Nov 2006 23:57:41 -0500 (EST)
From: Igor Peshansky <pechtcha AT cs DOT nyu DOT edu>
Reply-To: cygwin AT cygwin DOT com
To: Eric Blake <ebb9 AT byu DOT net>
cc: autoconf AT gnu DOT org, cygwin AT cygwin DOT com, bob_rossi AT cox DOT net
Subject: Re: cygwin -mno-cygwin AC_CHECK_SIZEOF
In-Reply-To: <456FA8DD.3030409@byu.net>
Message-ID: <Pine.GSO.4.63.0611302348180.17676@access1.cims.nyu.edu>
References: <20061201023212 DOT GH19404 AT cox DOT net> <456FA8DD DOT 3030409 AT byu DOT net>
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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 better worded, on a binary mount, cygwin's cat treats \r literally,
> like any other unix implementation of cat would do.

Well, actually, Cygwin's cat *always* treats \r literally, since it always
opens the file in binary mode.

> >   ac_cv_sizeof_int=`cat conftestval`
> > results in "4\r", which breaks the configure.in scripts that check with
> > if statements for "$ac_cv_sizeof_int" = "4".
> >
> > What is the best way to resolve something like this?
>
> Perhaps experiment with a cygwin text mount, so that cygwin cat will
> ignore the \r.

So the above solution will not help in this case...

> 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.

> 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.
	Igor
-- 
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