Re: Shared library versioning

[Anthony DeRobertis <anthony@derobert.net>]

Alexis.Papadopoulos@imag.fr wrote:

> g.h :
> template <class T>
> void g (T x);
> 
> g.cc :
> template <class T>
> void g (T x) {
>    cout << x;
> }
> 
> The .h file has to include the .cc one in order for the compilation to work.
> That leads to a shared library that we'll call libg.so.1.0.0
> Let's say now that I compile a program `prgm` and link it against the above library.

There are two issues here. The first is that you are not really linking
against the code in the shared library. GCC does not support template
export (for damn good reasons, really), and certainly does not support
it through shared libraries. In all likelyhood, the compiler is actually
inlining g().

If you were really using the shared library, you would not have to
include the .cc file. You're not. Your .so most likely does not even
export the instantiation of g<T> you need.