How to detect the presence of a static member function with certain signature?

Question

I found several questions & answers on SO dealing with detecting at compile time (via SFINAE) whether a given class has a member of certain name, type, or signature. How

Answer 1

Following may help: (https://ideone.com/nDlFUE)

#include 

#define DEFINE_HAS_SIGNATURE(traitsName, funcName, signature)               \
    template                                                    \
    class traitsName                                                        \
    {                                                                       \
    private:                                                                \
        template struct helper;                              \
        template                                                \
        static std::uint8_t check(helper*);           \
        template static std::uint16_t check(...);               \
    public:                                                                 \
        static                                                              \
        constexpr bool value = sizeof(check(0)) == sizeof(std::uint8_t); \
    }

Then define a traits:

DEFINE_HAS_SIGNATURE(has_foo, T::foo, void (*)(void));