It is quite useful to know which ZeroMQ version you are using. Knowing the exact version is helpful in some scenarios to avoid unwanted surprises. For example, there are some differences between ZeroMQ 2.x and ZeroMQ 3.x, such as deprecated methods; therefore, if you know the exact ZeroMQ version you have on your machine, you would avoid using deprecated methods.

#include <stdio.h>
#include "zmq.h"

int main (int argc, char const *argv[]) {
  int major, minor, patch;
  zmq_version(&major, &minor, &patch);
  printf("Installed ZeroMQ version: %d.%d.%d
", major, minor, patch);
    
  return 0;
}