Splitting templated C++ classes into .hpp/.cpp files--is it possible?

Question

I am getting errors trying to compile a C++ template class which is split between a .hpp and .cpp file:

$ g++ -c -o main.o main.cpp         


        

Answer 1

The problem is that a template doesn't generate an actual class, it's just a template telling the compiler how to generate a class. You need to generate a concrete class.

The easy and natural way is to put the methods in the header file. But there is another way.

In your .cpp file, if you have a reference to every template instantiation and method you require, the compiler will generate them there for use throughout your project.

new stack.cpp:

#include 
#include "stack.hpp"
template  stack::stack() {
        std::cerr << "Hello, stack " << this << "!" << std::endl;
}
template  stack::~stack() {
        std::cerr << "Goodbye, stack " << this << "." << std::endl;
}
static void DummyFunc() {
    static stack stack_int;  // generates the constructor and destructor code
    // ... any other method invocations need to go here to produce the method code
}