separating out Javier's program

src/15_3_chainlistener.c

@@ -0,0 +1,42 @@
+#include <czmq.h>
+int main(int argc, char ** argv) {
+
+  char *zmqserver;
+  char *topic;
+
+  if (argc < 3) {
+    printf("\nUSAGE:\nchainlistener <tcp://localhost:port> <topic>\n\n");
+    return 0;
+  } else {
+    zmqserver = argv[1];
+    topic = argv[2];
+  }
+
+  zsock_t *socket = zsock_new_sub(zmqserver, topic);
+  assert(socket);
+
+  while(1) {
+    zmsg_t *msg;
+    int rc = zsock_recv(socket, "m", &msg);
+    assert(rc == 0);
+
+    char *header = zmsg_popstr(msg);
+    zframe_t *zdata = zmsg_pop(msg);
+    unsigned int *no = (unsigned int*)zmsg_popstr(msg);
+
+    char *data = zframe_strhex(zdata);
+    int len = zframe_size(zdata);
+    printf("Size: %d\n", len);
+    printf("Data: %s", data);
+    printf("\nNo: %d\n", *no);
+
+    free(header);
+    free(data);
+    free(no);
+    free(zdata);
+    zmsg_destroy(&msg);
+    sleep(1);
+ }
+  zsock_destroy(&socket);
+  return 0;
+}