Question

I am working on an API in C++ and trying /really/ hard not to use RTTI, (Run-Time Type Information), to implement some dependency injection functionality.

I believe I can do this, but by utilizing templates–but it got me wondering:

When the templates are “expanded” and implemented by the compiler, do they in fact introduce a circular dependency, (either compile time or run time), when the template class is implemented in a framework library, and the client of that class is in a upper tiered library?

Thanks for your help!

#include <string>

/************************************************************/
// Implemented in Framework.lib
namespace Framework 
{
    template<typename ShapeTemplateType>
    class Utility
    {           
        void Do()
        {
            ShapeTemplateType x;
            (void) x;
        }
    };
} // End namespace Framework 

/************************************************************/
// Implemented in Application.lib
namespace Application
{
    class StateObject
    {
        int i;
    };

    class Facade
    {
        Framework::Utility<StateObject> state;
    };
} // End Namespace Application


/********************************************************************/
// Implemented in Client
int main(int args, char* argv[])
{
    Application::Facade facade;

    //Derived d;
    return 0;
}

Answer 1

The code for the template is generated in the compilation unit where it is instantiated. In your example, the resulting machine code will be in Application.lib.