Void function: a function-definition is not allowed here before '{' token

[Deltaflyer]

The interpreter complains about the following lines:

@kelvinkkong

void bONPopCallback(void *ptr) {  // Release event for button
analogWrite(motorPin, fanSpeed);  // Turn ON fan
}
void bOFFPopCallback(void *ptr) { // Release event for button
analogWrite(motorPin, 0);  // Turn OFF fan
}
void bFMinus2PopCallback (void *ptr) {
analogWrite(motorPin, 255 / 4); // 25% speed
}
void bFMinusPopCallback (void *ptr) {
//fanSpeed = fanSpeed - 5; //Minus 5 to current value of counter - Couldn't get this to work.
analogWrite(motorPin, 255 / 2); // 50% speed
}
void bFPlusPopCallback (void *ptr) {
//fanSpeed = fanSpeed + 5; //Plus 5 to current value of counter - Couldn't get this to work.
  analogWrite(motorPin, 255 * 3 / 4); // 75% speed
}
void bFPlus2PopCallback (void *ptr) {

  analogWrite(motorPin, 255); // 100% speed
}

I can imagine that he doesn't like the spelling (void * ptr). but I am not sure how it (if wrong) has to be spelled correctly.