Creating shared lib out of statical libs..

Question

Hello!
Over here we are trying to create a shared lib (.so) by doing
CC -G -o foo.so -h libfoo.so object.o -lbar -lgaz
Basically we want all functionality in the libbar.a and libgaz.a, but the resulting file, libfoo.so seems a little bit small..
Can we assume that the linker does smart linking and removes code from the libs that isn't used from itself? (to be honest sounds like a good idea :-))
Meanwhile, is there a good way to do this?? Should we do something like
CC -G -o foo.so -h libfoo.so object.o libbar.a libgaz.a
instead??
Can't find much about this in the documentation.. Don't know if I just haven't searched the wrong places??
/Andy

Answer 1

Hi There,
The first thing I will suggest you is the
document to read. C++ User's Guide for
Forte developer 6 update 2 - chapter 16 on
building libraries in C++ environment.
Are these libbar.a and libgaz.a archived libraries using C or C++? If these libraries are C
then you can convert them in .so using the following command.
cc -G -o libmylib.so.1 -zallextract libmylib.a
The main difference between linking with a archive and building a shared object is that the shared object is a indivisable unit. When you link against a archive you only get those components of the archive which the linking application directly references.
So - if you build a shared library with '-zallextract' you will get everything in the archive included in the shared library. This might be exactly what you intend and not cause a problem - but it depends upon what is in the archive and is up to you how you are using it.
I hope this helps.
...jagruti
Developers Technical Support
Sun Microsystems, http://www.sun.com/developers/support