//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <string>
// void swap(basic_string& c)
// noexcept(!allocator_type::propagate_on_container_swap::value ||
// __is_nothrow_swappable<allocator_type>::value);
//
// In C++17, the standard says that swap shall have:
// noexcept(allocator_traits<Allocator>::propagate_on_container_swap::value ||
// allocator_traits<Allocator>::is_always_equal::value);
// This tests a conforming extension
#include <string>
#include <cassert>
#include "test_allocator.h"
template <class T>
struct some_alloc
{
typedef T value_type;
some_alloc() {}
some_alloc(const some_alloc&);
void deallocate(void*, unsigned) {}
typedef std::true_type propagate_on_container_swap;
};
template <class T>
struct some_alloc2
{
typedef T value_type;
some_alloc2() {}
some_alloc2(const some_alloc2&);
void deallocate(void*, unsigned) {}
typedef std::false_type propagate_on_container_swap;
typedef std::true_type is_always_equal;
};
int main()
{
#if __has_feature(cxx_noexcept)
{
typedef std::string C;
C c1, c2;
static_assert(noexcept(swap(c1, c2)), "");
}
{
typedef std::basic_string<char, std::char_traits<char>, test_allocator<char>> C;
C c1, c2;
static_assert(noexcept(swap(c1, c2)), "");
}
{
typedef std::basic_string<char, std::char_traits<char>, some_alloc<char>> C;
C c1, c2;
#if TEST_STD_VER >= 14
// In c++14, if POCS is set, swapping the allocator is required not to throw
static_assert( noexcept(swap(c1, c2)), "");
#else
static_assert(!noexcept(swap(c1, c2)), "");
#endif
}
#if TEST_STD_VER >= 14
{
typedef std::basic_string<char, std::char_traits<char>, some_alloc2<char>> C;
C c1, c2;
// if the allocators are always equal, then the swap can be noexcept
static_assert( noexcept(swap(c1, c2)), "");
}
#endif
#endif
}