libcxx/test/std/strings/basic.string/string.cons/dtor.pass.cpp

   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
  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
  55 int main(int, char**) {
  56   test();
  57 #if TEST_STD_VER > 17
  58   static_assert(test());
  59 #endif
  60
  61   return 0;
  62 }