1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // <functional> 11 12 // template <class T> 13 // struct hash 14 // : public unary_function<T, size_t> 15 // { 16 // size_t operator()(T val) const; 17 // }; 18 19 // Not very portable 20 21 #include <system_error> 22 #include <cassert> 23 #include <type_traits> 24 25 void 26 test(int i) 27 { 28 typedef std::error_code T; 29 typedef std::hash<T> H; 30 static_assert((std::is_base_of<std::unary_function<T, std::size_t>, 31 H>::value), ""); 32 H h; 33 T ec(i, std::system_category()); 34 assert(h(ec) == i); 35 } 36 37 int main() 38 { 39 test(0); 40 test(2); 41 test(10); 42 } 43
