Re: [i386] Why g++ _always_ link an executable with libm.so?

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