libcxx/test/std/thread/futures/futures.task/futures.task.members/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 // void swap(packaged_task& other);
  17
  18 #include <future>
  19 #include <cassert>
  20
  21 #include "test_macros.h"
  22
  23 class A
  24 {
  25     long data_;
  26
  27 public:
  28     explicit A(long i) : data_(i) {}
  29
  30     long operator()(long i, long j) const {return data_ + i + j;}
  31 };
  32
  33 int main(int, char**)
  34 {
  35     {
  36         std::packaged_task<double(int, char)> p0(A(5));
  37         std::packaged_task<double(int, char)> p;
  38         p.swap(p0);
  39         assert(!p0.valid());
  40         assert(p.valid());
  41         std::future<double> f = p.get_future();
  42         p(3, 97);
  43         assert(f.get() == 105.0);
  44     }
  45     {
  46         std::packaged_task<double(int, char)> p0;
  47         std::packaged_task<double(int, char)> p;
  48         p.swap(p0);
  49         assert(!p0.valid());
  50         assert(!p.valid());
  51     }
  52
  53   return 0;
  54 }