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Date: Fri, 14 Dec 2001 11:36:19 +0100
From: Corinna Vinschen <cygwin AT cygwin DOT com>
To: cygwin <cygwin AT cygwin DOT com>
Subject: Re: duplicate regexec/regcomp functions detected
Message-ID: <20011214113619.J740@cygbert.vinschen.de>
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References: <015501c18413$5a3d81f0$9a5f07d5 AT BRAMSCHE>
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In-Reply-To: <015501c18413$5a3d81f0$9a5f07d5@BRAMSCHE>; from Ralf.Habacker@freenet.de on Thu, Dec 13, 2001 at 09:18:39PM +0100

On Thu, Dec 13, 2001 at 09:18:39PM +0100, Ralf Habacker wrote:
> Hi all,
> 
> kde needs the regexp functions regexec and regcomp.
> 
> The cygwin lib contains the System V8 function call style, while the pcre package (pcreposix)
> provides another style (the system V style I guess). The problem is now, that both libs
> supports the same names for regexec and regcomp but with different parameter/return types.
> This results sometimes in execution failures if the libs are not in the right order like
> shown in the following example.
> 
> pcre regexp wanted
> 
> $ gcc ... -lpcreposix -lcygwin   -> okay
> 
> $ gcc ... -lpthreads|-lm|-lc -lpcreposix -lcygwin   -> failure: the functions in cygwin lib
> are used

But that order should never happen EXCEPT you're making the big
mistake to give `-lm' or `-lc' on the command line explicitly.
Since -lcygwin is appended automagically and libc.a and libm.a
are the same library anyway, the answer is simply, "Don't do that."

> Especially in libtool related environment with many dependency libs like kde this causes much
> trouble.
> 
> Should it not be better, to remove the regexp support from cygwin into a seperate lib, so
> that users has an easier possibility to choose which regexp style they want ?

We didn't want that for compatibility reasons.  We often already
discussed to trash the V8 implementation in favor of a POSIX
implementation but that would break older applications which we're
trying to avoid.

Btw., we have another POSIX regex library besides pcreposix: -lregex.
It's somewhat smaller and it's also DLLized.  OpenSSH's configure.ac
file has a special check to see if a regex lib exists and if the base
regexp implementation in the std C lib is POSIX compliant.  We added
that to the OpenSSH configury a few weeks ago to make Cygwin happy.

Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                                mailto:cygwin AT cygwin DOT com
Red Hat, Inc.

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