Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sources.redhat.com/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sources.redhat.com/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
X-pair-Authenticated: 217.4.28.105
Message-ID: <3D2EE0C2.78D6@multimediaware.com>
Date: Fri, 12 Jul 2002 15:59:30 +0200
From: Wolfgang Hesseler <qv AT multimediaware DOT com>
MIME-Version: 1.0
To: egor duda <cygwin AT cygwin DOT com>
Subject: Re: Bug: BSS segment in COFF files
References: <3D2EA2E2 DOT 2881 AT multimediaware DOT com>
	 <8772121004 DOT 20020712145134 AT logos-m DOT ru> <3D2EBFC2 DOT 6973 AT multimediaware DOT com>
	 <9975891676 DOT 20020712155424 AT logos-m DOT ru> <3D2EC616 DOT 19DA AT multimediaware DOT com> <9382195250 DOT 20020712173928 AT logos-m DOT ru>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

> >> >> If you run gcc with '--save-temps' flag, and then look into
> >> >> 'yourfile.s' file, you'll see that uninitialized data is tagged as
> >> >> "common" (using '.comm' directive) and is put to bss only by linker
> >> >> when final executable is created. To turn this feature off, use
> >> >> '-fno-common' flag when compiling your object file.

I just noticed that this doesn't help at all. When analyzing the 
object file with IDA you'll see that the BSS section has length 0.
Thus, when you link several object files together, all variables
are at the same memory position. I think it's a problem with the
Assembler that doesn't generate valid COFF files. BTW, when 
compiling the same program under Linux the BSS section is not 0. So,
it seems that the problem is Cygwin (COFF) specific.

So far, the only way to reserve memory for a variable is to make
it 0-initialized.


--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/