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 // <iterator> 11 // template <class C> constexpr auto empty(const C& c) -> decltype(c.empty()); // C++17 12 // template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept; // C++17 13 // template <class E> constexpr bool empty(initializer_list<E> il) noexcept; // C++17 14 15 #if __cplusplus <= 201402L 16 int main () {} 17 #else 18 19 #include <iterator> 20 #include <cassert> 21 #include <vector> 22 #include <array> 23 #include <list> 24 #include <initializer_list> 25 26 template<typename C> 27 void test_const_container( const C& c ) 28 { 29 assert ( std::empty(c) == c.empty()); 30 } 31 32 template<typename T> 33 void test_const_container( const std::initializer_list<T>& c ) 34 { 35 assert ( std::empty(c) == (c.size() == 0)); 36 } 37 38 template<typename C> 39 void test_container( C& c ) 40 { 41 assert ( std::empty(c) == c.empty()); 42 } 43 44 template<typename T> 45 void test_container( std::initializer_list<T>& c ) 46 { 47 assert ( std::empty(c) == (c.size() == 0)); 48 } 49 50 template<typename T, size_t Sz> 51 void test_const_array( const T (&array)[Sz] ) 52 { 53 assert (!std::empty(array)); 54 } 55 56 int main() 57 { 58 std::vector<int> v; v.push_back(1); 59 std::list<int> l; l.push_back(2); 60 std::array<int, 1> a; a[0] = 3; 61 std::initializer_list<int> il = { 4 }; 62 63 test_container ( v ); 64 test_container ( l ); 65 test_container ( a ); 66 test_container ( il ); 67 68 test_const_container ( v ); 69 test_const_container ( l ); 70 test_const_container ( a ); 71 test_const_container ( il ); 72 73 static constexpr int arrA [] { 1, 2, 3 }; 74 test_const_array ( arrA ); 75 } 76 77 #endif 78
