mosquitto_connect_async seems to be blocking since version 1.2

[onaips]

I just downloaded version 1.2 and mosquitto_connect_async is now blocking when connecting to server. Such behavior was not present on the version 1.1.3 i was using.

[Roger Light (roger.light)]

In 1.1.x mosquitto_connect_async() didn't actually attempt any connection. It does now and makes a non-blocking connection. The problem is that the DNS lookups are still blocking. If you use an IP address instead of a hostname it should work just fine. I realise this isn't an ideal situation!

[Karl Palsson (ubuntu-tweak)]

fwiw, our 1.1 code aborted if connect_async returned non success. Because in the past, it always succeeded. Now that it does make a connection attempt, blocking or not, we need to not actually care about the response being successful or not (other than MOSQ_ERR_INVAL) and simply carry on and make the call to _loop_start()

#define CFG_DEFAULT_MQ_HOST "127.0.0.1"
        int connect_result = mosquitto_connect_async(st->mosq, CFG_DEFAULT_MQ_HOST, 1883, 90);

        if (connect_result != MOSQ_ERR_SUCCESS) {
                // oh, this looks really bad when this happens
                WLOG("Failed to create a thread for connecting to %s: code:%d, reason: %s\n",
   CFG_DEFAULT_MQ_HOST, connect_result, strerror(errno));
                // XXX DON'T ABORT HERE ON MOSQUITTO 1.2!
               // return false;
        }
        // okay, "connected", lets go...
        // start looping in a thread, this also reconnects if necessary!!
        ILOG("Starting mosquitto loop thread\n");
        int loop_result = mosquitto_loop_start(st->mosq);
        if (loop_result != MOSQ_ERR_SUCCESS) {
                // oh, this looks really bad again give up!
                WLOG("Failed to create a thread for looping mosquitto.\n");
                return false;
        }
        // everything fine
        return true;

User error I guess :)