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

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Here’s a possible implementation relying on C++11 features. It correctly detects the function even if it’s inherited (unlike the solution in the accepted answer, as Mike Kinghan observes in his answer).

The function this snippet tests for is called serialize:

#include <type_traits>

// Primary template with a static assertion
// for a meaningful error message
// if it ever gets instantiated.
// We could leave it undefined if we didn't care.

template<typename, typename T>
struct has_serialize {
    static_assert(
        std::integral_constant<T, false>::value,
        "Second template parameter needs to be of function type.");
};

// specialization that does the checking

template<typename C, typename Ret, typename... Args>
struct has_serialize<C, Ret(Args...)> {
private:
    template<typename T>
    static constexpr auto check(T*)
    -> typename
        std::is_same<
            decltype( std::declval<T>().serialize( std::declval<Args>()... ) ),
            Ret    // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        >::type;  // attempt to call it and see if the return type is correct

    template<typename>
    static constexpr std::false_type check(...);

    typedef decltype(check<C>(0)) type;

public:
    static constexpr bool value = type::value;
};

Usage:

struct X {
     int serialize(const std::string&) { return 42; } 
};

struct Y : X {};

std::cout << has_serialize<Y, int(const std::string&)>::value; // will print 1

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