MQTT Error in IDE (Troubleshooting)

[papa]

        Papa: Recently nin34 personal messaged:

Hi there,  I'm facing an error while trying to run a code for IoT Based Smart Parking System using Adafruit IO.

WARNING: Spurious .github folder in 'Adafruit MQTT Library' library

C:\Users\ninad\Documents\Arduino\Sketches\sketch_feb20a\sketch_feb20a.ino: In function 'void loop()':

sketch_feb20a:85: error: 'MQTT_connect' was not declared in this scope
        MQTT_connect();

Could you please help me? Thanks!

iotdesignpro.com/projects/iot-based-smart-parking-using-esp8266
      You can find the entire code on the above link ^

[papa]

        I looked at the sketch at iotdesignpro.com/projects/iot-based-smart-parking-using-esp8266

MQTT_connect() is a function the sketch calls, but it is nowhere in the sketch itself. At first I thought perhaps MQTT_connect() is supposed to be found in one of the #included libraries, I would guess "Adafruit_MQTT.h" or "Adafruit_MQTT_Client.h"  However, I did not find MQTT_connect() in either of those libraries.  That is, MQTT_connect() is not declared (set up) anywhere reachable by how you are using the sketch so it throws an error.

Looking further here: github.com/adafruit/Adafruit_MQTT_Library/blob/master/examples/mqtt_esp8266/mqtt_esp8266.ino
... I found this just before void setup() in an example sketch:

// Bug workaround for Arduino 1.6.6, it seems to need a function declaration
// for some reason (only affects ESP8266, likely an arduino-builder bug).
        void MQTT_connect();

        papa:  so try this in the sketch ...   Find these two lines:

Adafruit_MQTT_Publish ExitSlot3 = Adafruit_MQTT_Publish(&mqtt,MQTT_NAME "/f/ExitSlot3");

void setup() {

& between the two above lines insert this line:
        void MQTT_connect();
================================
That is, try this: make the two lines like the following 3 lines (so MQTT_connect is "declared" before it's used in void loop():

Adafruit_MQTT_Publish ExitSlot3 = Adafruit_MQTT_Publish(&mqtt,MQTT_NAME "/f/ExitSlot3");

void MQTT_connect();

void setup() {