CODEWITHSUNDEEP
linkerzeromq
F. Aydemir
F. Aydemir

Reputation: 2735

zmq.hpp - Undefined Reference `zmq_poll'

I am using zeromq api for my application and having below indicated link problems. I have installed both zeromq and czmq tar ball to my ubuntu 12.10 system and verified that the necessary header files (e.g. zmq.h)are present under /usr/local/include. Could you please tell me why I am getting these link problems? What would be possible solution. I also installed zmq c++ bindings (zmq.hpp).

/XXXX.cpp:92: undefined reference to `zmq_poll'
CMakeFiles/dummy.dir/__/xxx_api/TheQueue.cpp.o: In function`zmq::error_t::error_t()':

/usr/local/include/zmq.hpp:76: undefined reference to `zmq_errno'
CMakeFiles/dummy.dir/__/xxx_api/TheQueue.cpp.o: In function `zmq::error_t::what() const':

 /usr/local/include/zmq.hpp:80: undefined reference to `zmq_strerror'
 CMakeFiles/dummy.dir/__/xxx/TheQueue.cpp.o: In function`zmq::context_t::context_t(int)':

/usr/local/include/zmq.hpp:241: undefined reference to `zmq_init'
CMakeFiles/dummy.dir/__/control_api/TheQueue.cpp.o: In function `zmq::context_t::close()':

/usr/local/include/zmq.hpp:267: undefined reference to `zmq_term'
CMakeFiles/dummy.dir/__/xxx_api/TheQueue.cpp.o: In function `zmq::socket_t::socket_t(zmq::context_t&, int)':

collect2: error: ld returned 1 exit status
make[2]: *** [/xxx/build_output/dummy] Error 1
make[1]: *** [/xxx/CMakeFiles/dummy.dir/all] Error 2

Upvotes: 2

Views: 5915

Answers (1)

Adam Miller
Adam Miller

Reputation: 1783

The following example works for me:

Here I have my file, containing the following: 

#include "cppzmq/zmq.hpp"
#include <string>
#include <iostream>

int main ()
{
    //  Prepare our context and socket
    zmq::context_t context (1);
    zmq::socket_t socket (context, ZMQ_REQ);

    std::cout << "Connecting to hello world server…" << std::endl;
    socket.connect ("tcp://localhost:5555");

    //  Do 10 requests, waiting each time for a response
    for (int request_nbr = 0; request_nbr != 10; request_nbr++) {
        zmq::message_t request (6);
        memcpy ((void *) request.data (), "Hello", 5);
        std::cout << "Sending Hello " << request_nbr << "…" << std::endl;
        socket.send (request);

        //  Get the reply.
        zmq::message_t reply;
        socket.recv (&reply);
        std::cout << "Received World " << request_nbr << std::endl;
    }
    return 0;
}

Then here I have the following command, which compiles it:

g++ test.cpp -o test -lzmq

To make zmq work on my linux machine, I simply downloaded zeromq as a tarball (for unix/linux) from their site. I then ran 

make && make install

Upvotes: 5

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