libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/swap.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: no-threads
  10 // UNSUPPORTED: c++03
  11
  12 // <future>
  13
  14 // class packaged_task<R(ArgTypes...)>
  15
  16 // template <class R, class... ArgTypes>
  17 //   void
  18 //   swap(packaged_task<R(ArgTypes...)>& x, packaged_task<R(ArgTypes...)>& y);
  19
  20 #include <future>
  21 #include <cassert>
  22
  23 #include "test_macros.h"
  24
  25 class A
  26 {
  27     long data_;
  28
  29 public:
  30     explicit A(long i) : data_(i) {}
  31
  32     long operator()(long i, long j) const {return data_ + i + j;}
  33 };
  34
  35 int main(int, char**)
  36 {
  37     {
  38         std::packaged_task<double(int, char)> p0(A(5));
  39         std::packaged_task<double(int, char)> p;
  40         swap(p, p0);
  41         assert(!p0.valid());
  42         assert(p.valid());
  43         std::future<double> f = p.get_future();
  44         p(3, 97);
  45         assert(f.get() == 105.0);
  46     }
  47     {
  48         std::packaged_task<double(int, char)> p0;
  49         std::packaged_task<double(int, char)> p;
  50         swap(p, p0);
  51         assert(!p0.valid());
  52         assert(!p.valid());
  53     }
  54
  55   return 0;
  56 }