How to use explicit template instantiation to reduce compilation time?

Question

It was suggested to use explicit template instantiation to reduce compilation time. I am wondering how to do it. For example

// a.h
template         


        

Answer 1

If you know that your template will be used only for certain types, lets call them T1,T2, you can move implementation to source file, like normal classes.

//foo.hpp
template
struct Foo {
    void f();
};

//foo.cpp
template
void Foo::f() {}

template class Foo;
template class Foo;