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 // <string_view>
10 
11 // constexpr const _CharT& back();
12 
13 #include <string_view>
14 #include <cassert>
15 
16 #include "test_macros.h"
17 
18 template <typename CharT>
19 bool test ( const CharT *s, size_t len ) {
20     typedef std::basic_string_view<CharT> SV;
21     SV sv ( s, len );
22     ASSERT_SAME_TYPE(decltype(sv.front()), typename SV::const_reference);
23     LIBCPP_ASSERT_NOEXCEPT(   sv.front());
24     assert ( sv.length() == len );
25     assert ( sv.front() == s[0] );
26     return &sv.front() == s;
27     }
28 
29 int main(int, char**) {
30     assert ( test ( "ABCDE", 5 ));
31     assert ( test ( "a", 1 ));
32 
33     assert ( test ( L"ABCDE", 5 ));
34     assert ( test ( L"a", 1 ));
35 
36 #if TEST_STD_VER >= 11
37     assert ( test ( u"ABCDE", 5 ));
38     assert ( test ( u"a", 1 ));
39 
40     assert ( test ( U"ABCDE", 5 ));
41     assert ( test ( U"a", 1 ));
42 #endif
43 
44 #if TEST_STD_VER >= 11
45     {
46     constexpr std::basic_string_view<char> sv ( "ABC", 2 );
47     static_assert ( sv.length() ==  2,  "" );
48     static_assert ( sv.front()  == 'A', "" );
49     }
50 #endif
51 
52   return 0;
53 }
54