Where to define C++ class member template function and functors that instantiate it?

Question

I have a class Foo which is used in a small standalone project. It has a class definition in Foo.h with the implementation for the class\' member functions in an implementat

Answer 1

My default would be to put the definition for the member function templates right in the .h file, like this:

class Foo
{
public: 
  template void DoSomething(T t);
};

// ... later...

template
void Foo::DoSomething(T t)
{
  // ...
}

If this is suboptimal for a particular case, then I'd take more heroic measures. Starting with #include-ing a .inc file with the definition at the end of the .h file, or possibly even doing explicit instantiations in the .cpp files where I needed the member function templates to be used.