Re: dlopen from dlopend library question

[Ralf Wildenhues]

Hi Gleb,

Sorry for the late response,

* Gleb Natapov wrote on Sun, Jul 17, 2005 at 11:39:34AM CEST:
> 
> I have library (lets say liba.so) that on startup checks available 
> hardware and loads appropriate plugin (say plugin.so) to drive the hardware.
> plugin.so uses symbols from liba.so. 
> 
> Everything works OK if liba.so linked with application, but if
> application is modular by itself and use module (say module.so) that
> is linked with liba.so then dlopen of plugin.so from liba.so fails with
> unresolved symbols.
> 
> How can I solve this issue?

If you use Libtool/libltdl for portable modules (which you do not seem
to do), look at Libtool branch-2-0 or CVS HEAD, which allows ltdlopen'ing
from libraries.  Make sure to read the corresponding documentation
pertaining to libltdl, make use of `-module' and `-export-dynamic'.

> PS: All this happens using linux system.

If you want to be GCC/GNU ld specific only, you can use --export-dynamic
for exporting symbols to dlopen'ed modules.

If this is not enough help, don't hesitate to ask for details.  If you
could provide a small example that reproduces the failure, the better.

Cheers,
Ralf