c++zeromqczmq

Moving cppzmq message_t to background thread

I have a receiver thread. I want to move the messages into a queue for background processors threads. To put it simply:

std::queue<zmq::message_t> qu;
zmq::message_t msg;
zmq::recv_result_t res = sock.recv(msg, zmq::recv_flags::none);
qu.push(std::move(message));

I get an error:

include/zmq.hpp:745:5: note: declared here
  745 |     message_t(const message_t &) ZMQ_DELETED_FUNCTION;

Even without std::move, it's still not working.

I understand that zmq::message_t are not supposed to be moved like that. What is the correct way of doing that (efficiently, without un needed copying)?

I would expect that message_t will hold the message data allocated on the heap, and that will be freed in the destructor of the message_t. In that case, I don't understand what is the issue here.

Solution

  • You could use

    qu.emplace(std::move(message))

    instead, or explicitly call move():

    qu.push(message_t{});
message.move(qu.back());