From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 74392 invoked by alias); 3 Jun 2016 16:14:38 -0000 Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Received: (qmail 74381 invoked by uid 89); 3 Jun 2016 16:14:37 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.3 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.2 spammy=strawberry, sk:portabl, resembling, Sincerely X-HELO: karasik.eu.org Received: from nataraj.karasik.eu.org (HELO karasik.eu.org) (194.28.255.22) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 03 Jun 2016 16:14:27 +0000 Received: from karasik.eu.org (karasik.eu.org [194.28.255.22]) by karasik.eu.org (Postfix) with ESMTP id B00F41177DD for ; Fri, 3 Jun 2016 18:14:19 +0200 (CEST) Received: (from dk@localhost) by karasik.eu.org (8.14.9/8.14.9/Submit) id u53GEJAV005478 for cygwin@cygwin.com; Fri, 3 Jun 2016 18:14:19 +0200 (CEST) (envelope-from dk) Date: Fri, 03 Jun 2016 16:14:00 -0000 From: Dmitry Karasik To: cygwin@cygwin.com Subject: bug: configuration problem in perl with gcc libs Message-ID: <20160603161419.GA5300@karasik2> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-SW-Source: 2016-06/txt/msg00040.txt.bz2 Hello, I'd like to report a configuration bug in perl. The problem arises when a 3-rd party module tries to build an extension using perl configuration with a gcc-specific library. Generally perl extensions don't have a way to specify library to link with directly, they do that through ExtUtils::MakeMaker, the standard tool for that. Which in turn tries to resolve '-llibname' using its own compile-time-configured internal list of lib paths. Everything works so far libraries are found in perl's libpth (see by running 'perl -V:libpth') which is /usr/lib on my machine. The problem arises when I need to link together with libgomp, which is not found there, being a gcc-version-specific library. For example, the following minimal Makefile.PL configure script use ExtUtils::MakeMaker; WriteMakefile(NAME => 'foo', LIBS => '-lgomp'); will emit a warning Warning (mostly harmless): No library found for -lgomp and removes -lgomp from the linker command, resulting in perl extension not being able to compile. The problem is confirmed, when, if I edit perl configuration file /usr/lib/perl5/5.22/i686-cygwin-threads-64int/Config.pm, everything works: ldlibpthname => 'PATH', - libpth => '/usr/lib', + libpth => '/usr/lib /usr/lib/gcc/i686-pc-cygwin/5.3.0', osname => 'cygwin', I believe perl needs to be built with the properly set/found libpth in advance. The diff below is the closest thing resembling a patch for the perl source package I could come with: --- Configure.0 2016-06-03 17:45:43.102008000 +0200 +++ Configure 2016-06-03 17:46:10.077558700 +0200 @@ -4948,6 +4948,16 @@ *) libpth="$libpth $j";; esac fi + # add gcc-specific libpath + if echo "$i" | grep -q "/usr/lib/gcc/"; then + j="`$echo $i|$sed 's,/include$,,'`" + if $test -d $j; then + case " $libpth " in + *" $j "*) ;; + *) libpth="$libpth $j";; + esac + fi + fi done libpth="`$echo $libpth|$sed 's/^ //'`" for xxx in $libpth $loclibpth $plibpth $glibpth; do The idea for the patch is taken from strawberry perl, which has the gcc libpath included in configuration. I couldn't find though exactly how they manage to include the path, during the configuration or when building, but it seems they somehow add it explicitly, using a custom tool for the MinGW perl build: https://github.com/StrawberryPerl/Perl-Dist-Strawberry/blob/master/share/portable/portable.perl.32#L60-L65 Hopefully this makes sense. -- Sincerely, Dmitry Karasik -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple