AMQP-CPP

EXISTING EVENT LOOPS

Both the pure AMQP::Connection as well as the easier AMQP::TcpConnection class allow you to integrate AMQP-CPP in your own event loop. Whether you take care of running the event loop yourself (for example by using the select() system call), or if you use an existing library for it (like libevent, libev or libuv), you can implement the "monitor()" method to watch the file descriptors and hand over control back to AMQP-CPP when one of the sockets become active.

For libev and libevent users, we have even implemented an example implementation, so that you do not even have to do this. Instead of implementing the monitor() method yourself, you can use the AMQP::LibEvHandler or AMQP:LibEventHandler classes instead:

#include <ev.h>
#include <amqpcpp.h>
#include <amqpcpp/libev.h>

int main()
{
    // access to the event loop
    auto *loop = EV_DEFAULT;

    // handler for libev (so we don't have to implement AMQP::TcpHandler!)
    AMQP::LibEvHandler handler(loop);

    // make a connection
    AMQP::TcpConnection connection(&handler, AMQP::Address("amqp://localhost/"));

    // we need a channel too
    AMQP::TcpChannel channel(&connection);

    // create a temporary queue
    channel.declareQueue(AMQP::exclusive).onSuccess([&connection](const std::string &name, uint32_t messagecount, uint32_t consumercount) {

        // report the name of the temporary queue
        std::cout << "declared queue " << name << std::endl;

        // now we can close the connection
        connection.close();
    });

    // run the loop
    ev_run(loop, 0);

    // done
    return 0;
}

The AMQP::LibEvHandler and AMQP::LibEventHandler classes are extended AMQP::TcpHandler classes, with an implementation of the monitor() method that simply adds the filedescriptor to the event loop. If you use this class however, it is recommended not to instantiate it directly (like we did in the example), but to create your own "MyHandler" class that extends from it, and in which you also implement the onError() method to report possible connection errors to your end users.

Currently, we have only added such an example TcpHandler implementation for libev and libevent. For other event loops (like libuv and boost asio) we do not yet have such examples.



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