xref: /llvm-project/libcxx/test/std/strings/basic.string/string.cons/dtor.pass.cpp (revision a40bada91aeda276a772acfbcae6e8de26755a11)
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
10 
11 // <string>
12 
13 // ~basic_string() // implied noexcept; // constexpr since C++20
14 
15 #include <string>
16 #include <cassert>
17 
18 #include "test_macros.h"
19 #include "test_allocator.h"
20 
21 template <class T>
22 struct throwing_alloc {
23   typedef T value_type;
24   throwing_alloc(const throwing_alloc&);
25   T* allocate(std::size_t);
26   ~throwing_alloc() noexcept(false);
27 };
28 
29 // Test that it's possible to take the address of basic_string's destructors
30 // by creating globals which will register their destructors with cxa_atexit.
31 std::string unused_string;
32 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
33 std::wstring unused_wide_string;
34 #endif
35 
36 static_assert(std::is_nothrow_destructible<std::string>::value, "");
37 static_assert(
38     std::is_nothrow_destructible< std::basic_string<char, std::char_traits<char>, test_allocator<char>>>::value, "");
39 LIBCPP_STATIC_ASSERT(
40     !std::is_nothrow_destructible< std::basic_string<char, std::char_traits<char>, throwing_alloc<char>>>::value, "");
41 
test()42 TEST_CONSTEXPR_CXX20 bool test() {
43   test_allocator_statistics alloc_stats;
44   {
45     std::basic_string<char, std::char_traits<char>, test_allocator<char>> str2((test_allocator<char>(&alloc_stats)));
46     str2 = "long long string so no SSO";
47     assert(alloc_stats.alloc_count > 0);
48     LIBCPP_ASSERT(alloc_stats.alloc_count == 1);
49   }
50   assert(alloc_stats.alloc_count == 0);
51 
52   return true;
53 }
54 
main(int,char **)55 int main(int, char**) {
56   test();
57 #if TEST_STD_VER > 17
58   static_assert(test());
59 #endif
60 
61   return 0;
62 }
63