Re: Avoiding useless library dependencies

[Jakub Wilk <jwilk@debian.org>]

* Nikolaus Rath <Nikolaus@rath.org>, 2011-05-22, 21:17:
> > > gcc -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions build/temp.linux-x86_64-2.7/src/llfuse.o -o build/lib.linux-x86_64-2.7/llfuse.so --as-needed -pthread -lfuse -lrt -ld
> >
> > You want to use "-Wl,--as-needed", not "--as-needed". ("--as-needed" 
> > is a linker option, not a compiler option.)
>
> Doesn't seem to make any difference:
>
> [...]
> gcc -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions build/temp.linux-x86_64-2.6/src/llfuse.o -o build/lib.linux-x86_64-2.6/llfuse.so -Wl,--as-needed -pthread -lfuse -lrt -ldl
> copying build/lib.linux-x86_64-2.6/llfuse.so -> src
>
> $ ldd src/llfuse.so
> 	linux-vdso.so.1 =>  (0x00007fff63dff000)
> 	libfuse.so.2 => /usr/lib/libfuse.so.2 (0x00007fe771490000)
> 	libpthread.so.0 => /lib/libpthread.so.0 (0x00007fe771274000)
> 	libc.so.6 => /lib/libc.so.6 (0x00007fe770ef0000)
> 	librt.so.1 => /lib/librt.so.1 (0x00007fe770ce8000)
> 	libdl.so.2 => /lib/libdl.so.2 (0x00007fe770ae4000)
> 	/lib64/ld-linux-x86-64.so.2 (0x00007fe77193b000)

Please keep in mind that ldd is recursive. Since libfuse.so.2 is linked 
with librt and libdl, these two will show up in ldd output regardless of 
whether llfuse is linked with them or not.

Use "readelf -d /path/to/library | grep NEEDED" instead of ldd.

--
Jakub Wilk