libcxx/test/std/thread/futures/futures.task/futures.task.members/reset.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 reset();
  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
  31     {
  32         return data_ + i + j;
  33     }
  34 };
  35
  36 int main(int, char**)
  37 {
  38     {
  39         std::packaged_task<double(int, char)> p(A(5));
  40         std::future<double> f = p.get_future();
  41         p(3, 97);
  42         assert(f.get() == 105.0);
  43         p.reset();
  44         p(4, 97);
  45         f = p.get_future();
  46         assert(f.get() == 106.0);
  47     }
  48 #ifndef TEST_HAS_NO_EXCEPTIONS
  49     {
  50         std::packaged_task<double(int, char)> p;
  51         try
  52         {
  53             p.reset();
  54             assert(false);
  55         }
  56         catch (const std::future_error& e)
  57         {
  58             assert(e.code() == make_error_code(std::future_errc::no_state));
  59         }
  60     }
  61 #endif
  62
  63   return 0;
  64 }