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Re: postdeps empty on OpenBSD
From: |
Ralf Wildenhues |
Subject: |
Re: postdeps empty on OpenBSD |
Date: |
Wed, 21 Sep 2005 10:13:29 +0200 |
User-agent: |
Mutt/1.4.1i |
Hi Olly, Brad,
[ quoting generously for the benefit of Brad; this thread is also at
http://lists.gnu.org/archive/html/libtool/2005-09/msg00070.html ]
* Olly Betts wrote on Tue, Sep 20, 2005 at 08:08:40PM CEST:
> I'm trying to link C++ code into a shared object for use as a Python
> module. I'm using libtool to do the linking. On Linux this works
> well, but on OpenBSD it fails with lots of C++ library symbols not
> found.
>
> The problem seems to be that on OpenBSD the shared object doesn't
> pull in libstdc++. Python isn't written in C++, so doesn't pull in
> libstdc++ either.
>
> I've found that if I explicitly link with -lstdc++ then it works on
> OpenBSD, which supports this theory. I could potentially just always
> explicitly link with -lstdc++, but I'm concerned that this could try
> to link in two different versions on a machine with multiple compilers
> installed.
>
> Comparing the generated libtool scripts on the 2 systems, I've noticed
> that postdeps is empty on OpenBSD. On Linux it is:
>
> postdeps="-lstdc++ -lm -lgcc -lc -lgcc"
>
> So this would seem to be on the right track.
>
> I don't entirely follow the logic which generates this, but it seems
> to come from the output of something like:
>
> g++ -shared -v /dev/null 2>&1|grep "\-L"
>
> On an x86 Linux box (Debian unstable) with g++ 3.3.6 this gives:
>
> /usr/bin/../lib/gcc-lib/i486-linux-gnu/3.3.6/collect2 --eh-frame-hdr -m
> elf_i386 -shared /usr/bin/../lib/gcc-lib/i486-linux-gnu/3.3.6/../../../crti.o
> /usr/bin/../lib/gcc-lib/i486-linux-gnu/3.3.6/crtbeginS.o
> -L/usr/bin/../lib/gcc-lib/i486-linux-gnu/3.3.6 -L/usr/bin/../lib/gcc-lib
> -L/usr/lib/gcc-lib/i486-linux-gnu/3.3.6
> -L/usr/bin/../lib/gcc-lib/i486-linux-gnu/3.3.6/../../..
> -L/usr/lib/gcc-lib/i486-linux-gnu/3.3.6/../../.. /dev/null -lstdc++ -lm
> -lgcc_s -lc -lgcc_s /usr/bin/../lib/gcc-lib/i486-linux-gnu/3.3.6/crtendS.o
> /usr/bin/../lib/gcc-lib/i486-linux-gnu/3.3.6/../../../crtn.o
>
> On an x86 OpenBSD 3.7 box with g++ 3.3.5 this gives:
>
> /usr/lib/gcc-lib/i386-unknown-openbsd3.7/3.3.5/collect2 --eh-frame-hdr
> -shared -Bdynamic -dynamic-linker /usr/libexec/ld.so /usr/lib/crtbeginS.o
> -L/usr/lib/gcc-lib/i386-unknown-openbsd3.7/3.3.5 /dev/null -lsupc++ -lgcc
> -lgcc /usr/lib/crtendS.o
>
> Note: -lsupc++ instead of -lstdc++.
>
> If I remove the "-shared" on OpenBSD I get -lstdc++ instead of -lsupc++.
>
> I don't know if it's relevant, but both systems have shared and static
> versions
> of libstdc++, but only static versions of libsupc++ and libgcc. The Linux
> system has a shared (only) libgcc_s, but the OpenBSD system doesn't have this
> at all.
>
> Is this a libtool issue, or should I be looking elsewhere?
Probably libtool needs to be adjusted (on OpenBSD,
output_verbose_link_cmd is set to `echo' in the C++ case).
Brad, you changed this with this patch:
http://lists.gnu.org/archive/html/libtool-patches/2004-07/msg00000.html
and presumably for good reason. However, I could not find the
corresponding discussion by searching of web archives. Unfortunately, I
don't have access to OpenBSD, either, at the moment, to test myself.
Could you be bothered to look at this issue?
Thanks,
Ralf
Re: postdeps empty on OpenBSD,
Ralf Wildenhues <=
- Re: postdeps empty on OpenBSD, Peter O'Gorman, 2005/09/21
- Re: postdeps empty on OpenBSD, Olly Betts, 2005/09/21
- Re: postdeps empty on OpenBSD, Thorsten Glaser, 2005/09/21
- Re: postdeps empty on OpenBSD, Ralf Wildenhues, 2005/09/21
- Re: postdeps empty on OpenBSD, Olly Betts, 2005/09/21
- Re: postdeps empty on OpenBSD, Ralf Wildenhues, 2005/09/22
- Re: postdeps empty on OpenBSD, Olly Betts, 2005/09/26