How to force inclusion of an object file in a static library when linking into executable?

Question

I have a C++ project that due to its directory structure is set up as a static library A, which is linked into shared library B, which is linked in

Answer 1

If you can use C++0x features of gcc (-std=c++0x), then the function default template arguments may do the trick. As of the current c++ standard, default arguments are not allowed for function templates. With these enabled in c++0x, you can do something like :-

In some header file of static library ...

template< class T = int >
void Af()
{
}

Then in its corresponding cpp file use explicit template instantiation...

template void Af();

This will generate the symbols for the function Af though it is not yet called/referenced. This won't affect the callers due to the fact that because of the default template argument, you need not specify a type. Just add the template before the function declaration and explicitly instantiate it in its implementation file.

HTH,