[lug] Shared library question

[D. Stimits]

Eric Weber wrote:
> 
> I'm trying to learn about creating shared libraries.  I wrote a small
> routine to pop up a message box, then tried to create a shared library
> using the following command:
> gcc `gtk-config --cflags` -c -fPIC -o libgmsg.so.0.0.1 gmsgbox.c
> 
> I then placed this library in /usr/lib, and included the link:
> ln -s libgmsg.so.0.0.1 libgmsg.so
> 
> I then compiled a program trying to link to this new library using the
> command:
> gcc `gtk-config --cflags` -o gtktxtvw gtktxtvw.o callbacks.o menu.o -lgmsg
> `gtk-config --libs`

Try adding this in to your second line (linking), near the start:
   -shared -Wl,-export-dynamic,-soname,libgmsg.so.0

I'm not sure you need all that, such as export-dynamic, but I don't
think it'll hurt.

> 
> Now, the compilation and linking works successfully, and the program runs
> as expected, including the calls to the routing in libgmsg.  However, the
> problem is that when I run ldd on gtktxtvw, the libgmsg library does not
> appear in the output, so it appears that libgmsg is being linked
> statically in my program.  Am I missing a step here in generating a shared
> library?  Thanks.
> 
> Eric Weber
> -------------------------------
> Department of Mathematics
> Texas A&M University
> http://www.math.tamu.edu/~weber
> 
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