1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14
10
11// <iterator>
12// template <class C> constexpr auto empty(const C& c) -> decltype(c.empty()); // C++17
13// template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept; // C++17
14// template <class E> constexpr bool empty(initializer_list<E> il) noexcept; // C++17
15
16#include <iterator>
17#include <cassert>
18#include <vector>
19#include <array>
20#include <list>
21#include <initializer_list>
22
23#include "test_macros.h"
24
25#if TEST_STD_VER > 14
26#include <string_view>
27#endif
28
29template<typename C>
30void test_const_container( const C& c )
31{
32// Can't say noexcept here because the container might not be
33 assert ( std::empty(c) == c.empty());
34}
35
36template<typename T>
37void test_const_container( const std::initializer_list<T>& c )
38{
39 assert ( std::empty(c) == (c.size() == 0));
40}
41
42template<typename C>
43void test_container( C& c )
44{
45// Can't say noexcept here because the container might not be
46 assert ( std::empty(c) == c.empty());
47}
48
49template<typename T>
50void test_container( std::initializer_list<T>& c )
51{
52 ASSERT_NOEXCEPT(std::empty(c));
53 assert ( std::empty(c) == (c.size() == 0));
54}
55
56template<typename T, std::size_t Sz>
57void test_const_array( const T (&array)[Sz] )
58{
59 ASSERT_NOEXCEPT(std::empty(array));
60 assert (!std::empty(array));
61}
62
63int main(int, char**)
64{
65 std::vector<int> v; v.push_back(x: 1);
66 std::list<int> l; l.push_back(x: 2);
67 std::array<int, 1> a; a[0] = 3;
68 std::initializer_list<int> il = { 4 };
69
70 test_container ( c&: v );
71 test_container ( c&: l );
72 test_container ( c&: a );
73 test_container ( c&: il );
74
75 test_const_container ( c: v );
76 test_const_container ( c: l );
77 test_const_container ( c: a );
78 test_const_container ( c: il );
79
80#if TEST_STD_VER > 14
81 std::string_view sv{"ABC"};
82 test_container ( sv );
83 test_const_container ( sv );
84#endif
85
86 static constexpr int arrA [] { 1, 2, 3 };
87 test_const_array ( array: arrA );
88
89 return 0;
90}
91

source code of libcxx/test/std/iterators/iterator.container/empty.pass.cpp