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
Message-ID: <002a01c41c24$afc043f0$6400a8c0@HPLAPTOP>
From: "Jay West" <jwest AT classiccmp DOT org>
To: "Cygwin List" <cygwin AT cygwin DOT com>
References: <010201c41beb$013a9ee0$033310ac AT kwcorp DOT com> <6 DOT 0 DOT 1 DOT 1 DOT 0 DOT 20040406115543 DOT 037c68e8 AT 127 DOT 0 DOT 0 DOT 1>
Subject: Re: Will using cygwin help with back-linking?
Date: Tue, 6 Apr 2004 17:15:33 -0500
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
X-IsSubscribed: yes

Larry wrote...
> Did you see this?
>
> <http://www.cygwin.com/ml/cygwin/2000-10/msg00451.html>

No I didn't, but thanks! Actually, no, it doesn't answer my question. It
does ask the precursor to my question, which is how to create a dlopenable
module. I'm well aware of how to do that on unix, using exactly the commands
he listed (main executable with --export-dynamic, module with -fpic and
ld -shareable -dynamic). He is generally asking how to do that with cygwin,
but there's no discussion of exactly what with, and if, backlinking is
supported on a cygwin-ized windows machine.

I will gladly do the legwork of figuring out the specifics of how to do it
on cygwin, but I was hoping someone could at least point me down the right
path. Let me be more specific, I see two alternatives:

I could just use --export-dynamic, -fpic, and ld -shareable -dynamic. Of
course, if cygwin doesn't provide a mechanism of backlinking (non-cygwin
windows apparently doesn't), then that's a bad path for me to head down. So
the question still stands - does cygwin-based windows take care of
backlinking unresolved symbols in a "dll" to the main calling executable?

Another possibility may be using libtool (libltdl), which according to the
docs will help in building the libraries correctly on various platforms. As
a matter of fact, libtool docs specifically say NOT to use the above method,
because of problems on windows & AIX. Of course I have no idea if libtool
(libltdl) will recognize that it's on a cygwin based machine and do it
correctly, as opposed to it just noticing I'm on a windows machine and "do
it wrong" (basically saying "unresolved symbols").

So I guess in the final analysis there are two specific questions: Does
cygwin-based windows take care of backlinking, and if so with what
tool/method, and  is it's method compatable with libtool in a transparent
way on Unix vs. Cygwin/Windows?

Thanks for any direction!

Jay West



--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/