第十三號艦隊
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tttt

Posted on Edited on 
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template <typename T>
struct has_member_foo
{
        template <typename U, void (U::*)()> struct SFINAE {};
        template <typename U> static char check(SFINAE<U, &U::foo>*);
        template <typename U> static int  check(...);
        static const bool value = sizeof(check<T>(0)) == sizeof(char);
};
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#include <utility>
template <typename T>
struct has_member_foo11
{
private:
        template<typename U> static auto check(int) ->
        decltype(std::declval<U>().foo(), std::true_type());

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

public:
        enum {
                value = std::is_same<decltype(check<T>(0)),std::true_type>::value
        };
};
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template <typename T, typename ...Args>
struct has_member_foo11
{
private:
        template<typename U> static auto check(int) ->
        decltype(std::declval<U>().foo(std::declval<Args>()...), std::true_type());

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

public:
        enum {
                value = std::is_same<decltype(check<T>(0)),std::true_type>::value
        };
};