How to store a templated function in a .cpp file?

Question

I have a header file that looks like this

// header.hpp
namespace n {
template <typename T>
T someFunc(int some_val);
}

and an implementation that seems to be incorrect:

// body.cpp
#include "header.hpp"
namespace n {
template int someFunc<int>(int some_val) {...}
template bool someFunc<bool>(int some_val) {...}
}

Question: How can I write type-specific implementations in a .cpp-file, if I have the definition of my templated function in the header?

Why do I want this?: In my case, someFunc calls different functions, depending on the type of T. So it is not truly generic, which is why I would like to have several implementations (an alternative would be to use this solution)

Sorry, for asking this simple question, but I only found solutions that explain how to store templated class-member-functions in .cpp files (compare post).

Dude! That is the same post I am linking to! It explains how to do that for templated classes. `someFunc` is not a function of a class. — User12547645, Mar 11 '20 at 20:53
As pointed out in https://stackoverflow.com/questions/495021/why-can-templates-only-be-implemented-in-the-header-file, there is an alternative solution for classes. Is there one for functions that are not part of a class? — User12547645, Mar 11 '20 at 20:55
What happens when you compile your template? Do you get any errors? If so, what are they? — Code-Apprentice, Mar 11 '20 at 20:55
explicit template instantiation cannot have a definition; if this definition is meant to be an explicit specialization, add '<>' after the 'template' keyword — User12547645, Mar 11 '20 at 20:56
Your templates evaluate to multiple `someFunc`'s with differing return types. You cannot overload on return types. — Brady Dean, Mar 11 '20 at 20:57
@BradyDean Well, I could just call `someFunc(...)` and `someFunc(...)`, right? — User12547645, Mar 11 '20 at 21:06

How to store a templated function in a .cpp file?

0 Answers0