Check if a class has a member function of a given signature

Question

I\'m asking for a template trick to detect if a class has a specific member function of a given signature.

The problem is similar to the one cited here http://www.go

Answer 1

You appear to want the detector idiom. The above answers are variations on this that work with C++11 or C++14.

The std::experimental library has features which do essentially this. Reworking an example from above, it might be:

#include 

// serialized_method_t is a detector type for T.serialize(int) const
template
using serialized_method_t = decltype(std::declval.serialize(std::declval()));

// has_serialize_t is std::true_type when T.serialize(int) exists,
// and false otherwise.
template
using has_serialize_t = std::experimental::is_detected_t;

If you can't use std::experimental, a rudimentary version can be made like this:

template 
using void_t = void;
template