| // PR c++/56208 |
| // { dg-do compile { target c++11 } } |
| |
| struct ostream { |
| ostream& operator<<(int); |
| }; |
| |
| struct sfinae_base { |
| |
| typedef char one; |
| typedef char (&two)[2]; |
| |
| template<class T> |
| static T make(); |
| |
| template<unsigned> struct ok { typedef int type; }; |
| |
| template<class U, class T> |
| static one test(decltype((make<U>() << make<T>()), 0)); |
| |
| template<class, class> |
| static two test(...); |
| }; |
| |
| template<class T> |
| struct is_printable : private sfinae_base |
| { |
| enum { value = sizeof(test<ostream&, T>(0)) == sizeof(one) }; |
| }; |
| |
| typedef int ok[is_printable<int>::value ? 1 : -1]; |
