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Date: Thu, 8 Jul 2004 10:54:52 -0400
From: Christopher Faylor <cgf-no-personal-reply-please AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: negative error status: gcc vs. cl
Message-ID: <20040708145452.GA14402@trixie.casa.cgf.cx>
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On Thu, Jul 08, 2004 at 10:25:09AM -0400, Igor Pechtchanski wrote:
>On Thu, 8 Jul 2004, Corinna Vinschen wrote:
>
>> On Jul  8 11:49, Daniel Lungu wrote:
>> > Feel like bash tcsh on Cygwin mess up with negative exit status from a cl
>> > compiled .exe
>>
>> The answer is "don't do that".  Use positive values in the range from
>> 0 to 255.  See
>> http://www.opengroup.org/onlinepubs/009695399/functions/exit.html
>
>Actually, it looks like another buglet in Cygwin.  The code in
>spawn_guts() in spawn.cc (line 847 in CVS HEAD) simply binary-ORs the
>exitcode value returned by GetExitCodeProcess with the "res" variable.
>However, the "res" variable is also used to carry some flags, and a
>negative exitcode, being a full DWORD, accidentally sets those, so all
>sorts of havoc can potentially occur (and I'm surprised that all that
>happens is the wrong exit code).

This is not a bug.  A cygwin program can't set a negative exit code.
Only the lower order 16 bits are used.  This is enforced by _exit.

If someone uses ExitProcess in a cygwin program, then well, err...

cgf

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