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Re: [i386] Why g++ _always_ link an executable with libm.so?
- From: Daniel Jacobowitz <drow at false dot org>
- To: gcc at gcc dot gnu dot org, linux-gcc at vger dot kernel dot org
- Date: Tue, 4 Jan 2005 17:05:23 -0500
- Subject: Re: [i386] Why g++ _always_ link an executable with libm.so?
- References: <20050105030102.G1437@natasha.ward.six>
On Wed, Jan 05, 2005 at 03:01:02AM +0500, Denis Zaitsev wrote:
> I've found some strange behaviour of g++: if it's used to produce an
> executable, i.e.:
>
> g++ xxx.C -o XXX
>
> then that XXX is linked with libm.so, regardless of the fact that math
> is not used in the program. Also, libstdc++.so and libgcc_s.so are
> linked too, even though they aren't needed as well.
>
> But if g++ is used to compilation only, and the link stage is done by
> gcc or ld, i.e:
>
> g++ -c xxx.C -o xxx.o
> gcc xxx.o -o XXX
>
> then neither of that 3 libs are linked (of course, if they aren't
> needed).
>
> Why g++ does so? Is it intentional? Or how this can be solved?
drow@nevyn:~% readelf -d /usr/lib/libstdc++.so.6 | grep NEEDED
0x00000001 (NEEDED) Shared library: [libm.so.6]
0x00000001 (NEEDED) Shared library: [libgcc_s.so.1]
0x00000001 (NEEDED) Shared library: [libc.so.6]
Libstdc++ needs libm.
--
Daniel Jacobowitz