I have the following code snippet. There the context.close() blocks forever. Does anyone have a hint on how to fix this? I suspect this is happening because I send a message but never receive an answer, as the close() doesn’t block if I do get a response. The question is, what if I don’t get a response? How can I close the context in this case without causing a deadlock? I use libzmq 4.3.4 and cppzmq 4.7.1.

zmq::context_t context(1);
zmq::socket_t socket1(context, zmq::socket_type::req);
const std::string foo("foo_");
socket1.connect("tcp://127.0.0.1:8889");    
zmq::message_t msg(foo.size());
std::memcpy(msg.data(), foo.c_str(), foo.size());
socket1.send(std::move(msg), zmq::send_flags::none);
socket1.set(zmq::sockopt::rcvtimeo, 500);
socket1.recv(msg);
socket1.disconnect("tcp://127.0.0.1:8889");
socket1.set(zmq::sockopt::linger, 0);
socket1.close();
context.close();