106 lines
2.2 KiB
C++
106 lines
2.2 KiB
C++
// { dg-options "-std=gnu++14" }
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// Copyright (C) 2013-2016 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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// 20.2.3 exchange [utility.exchange]
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#include <utility>
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#include <type_traits>
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#include <testsuite_hooks.h>
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void
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test01()
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{
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const unsigned val = 4;
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int i = 1;
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auto prev = std::exchange(i, val);
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static_assert( std::is_same<decltype(prev), int>::value, "return type" );
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VERIFY( i == 4 );
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VERIFY( prev == 1 );
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prev = std::exchange(i, 3);
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VERIFY( i == 3 );
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VERIFY( prev == 4 );
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}
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// Default construction from empty braces
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void
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test02()
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{
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bool test __attribute__((unused)) = true;
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struct DefaultConstructible
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{
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DefaultConstructible(int i = 0) : value(i) { }
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int value;
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};
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DefaultConstructible x = 1;
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auto old = std::exchange(x, {});
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VERIFY( x.value == 0 );
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VERIFY( old.value == 1 );
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}
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int f(int) { return 0; }
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double f(double) { return 0; }
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// Deduce type of overloaded function
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void
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test03()
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{
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bool test __attribute__((unused)) = true;
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int (*fp)(int);
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std::exchange(fp, &f);
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VERIFY( fp != nullptr );
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}
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void test04()
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{
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struct From { };
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struct To {
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int value = 0;
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To() = default;
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To(const To&) = default;
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To(const From&) = delete;
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To& operator=(const From&) { value = 1; return *this; }
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To& operator=(From&&) { value = 2; return *this; }
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};
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To t;
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From f;
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auto prev = std::exchange(t, f);
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VERIFY( t.value == 1 );
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VERIFY( prev.value == 0 );
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prev = std::exchange(t, From{});
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VERIFY( t.value == 2 );
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VERIFY( prev.value == 1 );
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}
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int
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main()
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{
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test01();
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test02();
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test03();
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test04();
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return 0;
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}
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