libcxx/test/std/thread/futures/futures.promise/set_lvalue.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(R& r);
  17
  18 #include <future>
  19 #include <cassert>
  20
  21 #include "test_macros.h"
  22
  23 int main(int, char**)
  24 {
  25     {
  26         typedef int& T;
  27         int i = 3;
  28         std::promise<T> p;
  29         std::future<T> f = p.get_future();
  30         p.set_value(i);
  31         int& j = f.get();
  32         assert(j == 3);
  33         ++i;
  34         assert(j == 4);
  35 #ifndef TEST_HAS_NO_EXCEPTIONS
  36         try
  37         {
  38             p.set_value(i);
  39             assert(false);
  40         }
  41         catch (const std::future_error& e)
  42         {
  43             assert(e.code() == make_error_code(std::future_errc::promise_already_satisfied));
  44         }
  45 #endif
  46     }
  47
  48   return 0;
  49 }