Re: shared library RTTI with gcc

[Ronan Collobert <collober@...>]

> True, RTTI should not be used as part of a library's public interface.
> Now try to explain that to all c++ programmers out there...  :-(

Wim, that is a very personal point of view, programmers have different 
needs. I could as well say we should all write clean C/C++ libraries, 
with all functions starting with a prefix (or using namespace with C++): 
we will then not have any names confusion problems and could open all 
libraries with RTLD_GLOBAL with no risk :)

> However I also have a problem with the behaviour of dlopen in Lua but
> is not related to C++ at all.

I agree, Mauro. The only difference is that a part of C++ language does 
even not work if you do not use RTLD_GLOBAL.

To avoid name collisions, gcc recommends namespaces. Quote from 
http://gcc.gnu.org/faq.html#dso ...
"If you are worried about different objects with the same name colliding 
during the linking or loading process, then you should use namespaces to 
disambiguate them. Giving distinct objects with global linkage the same 
name is a violation of the One Definition Rule (ODR)"

> I actually _want_ one of my shared object's symbols exported to all
> subsequent modules. This is because I have many modules with common
> code, that should stay in the same place.

Yeah. In the end, if you have many clean C or C++ libraries which 
depends on each other, or C++ libraries which uses RTTI you might want 
to use RTLD_GLOBAL. If you have C or C++ libraries were you are not sure 
about name collisions (especially if it not your library) RTLD_LOCAL is 
the way. So a flag in package.loadlib would do the job, as you say.

Ronan.