libcxx/test/std/thread/futures/futures.promise/set_lvalue_at_thread_exit.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 promise<R>
  15
  16 // void promise<R&>::set_value_at_thread_exit(R& r);
  17
  18 #include <future>
  19 #include <memory>
  20 #include <cassert>
  21
  22 #include "make_test_thread.h"
  23 #include "test_macros.h"
  24
  25 int i = 0;
  26
  27 void func(std::promise<int&> p)
  28 {
  29     p.set_value_at_thread_exit(i);
  30     i = 4;
  31 }
  32
  33 int main(int, char**)
  34 {
  35     {
  36         std::promise<int&> p;
  37         std::future<int&> f = p.get_future();
  38         support::make_test_thread(func, std::move(p)).detach();
  39         assert(f.get() == 4);
  40     }
  41
  42   return 0;
  43 }