<html>
    <head>
      <base href="https://llvm.org/bugs/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - std::promise/future deadlock"
   href="https://llvm.org/bugs/show_bug.cgi?id=30376">30376</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>std::promise/future deadlock
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libc++
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Macintosh
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>MacOS X
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>All Bugs
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>vrba@mixedrealities.no
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>The bug happens with "Apple LLVM 7.0.0" (clang 7) on OSX 10.11.1 (El Capitan)
with XCode 7.0.1. The program below will write out a series of numbers and
after a short while hang, whereas it shouldn't. It runs flawlessly on Linux.

#include <iostream>
#include <thread>
#include <future>
#include <boost/asio.hpp>

using std::cout;
using std::endl;

static boost::asio::io_service io;

static void asio_thread()
{
    boost::asio::io_service::work work(io);
    cout << "STARTING ASIO" << endl;
    io.run();
    cout << "STOPPING ASIO" << endl;
}

static int poll()
{
  static int n;

  std::promise<int> promise;
  auto fut = promise.get_future();

  io.post([&promise]() {
    promise.set_value(n++);
  });

  return fut.get();
}

int main()
{
  std::thread thread(asio_thread);

  size_t n = 0;

  while (1)
    cout << "POLL: " << poll() << "\n";

  return 0;
}</pre>
        </div>
      </p>
      <hr>
      <span>You are receiving this mail because:</span>
      
      <ul>
          <li>You are on the CC list for the bug.</li>
      </ul>
    </body>
</html>