CODEWITHSUNDEEP
c++arduino
jakkubu
jakkubu

Reputation: 43

If statement with function as a condition in Arduino without () works fine

I was using function returning bool as a condition in if statement in Arduino:

bool conditionFunc(){
 return true;
}
void setup(){}

void loop(){
  if (conditionFunc){
  }
}

In my opinion I should do:

if (conditionFunc()){ //added ()
  doSometing;
}

But the first one didn't cause any error during verifying, and code worked (according to my client - I didn't build a circuit - it was simple job so I didn't have to do it). I found it by accident. I don't have any variable named conditionFunc. In my opinion error should be discovered during verifying in Arduino IDE.

I'm confused. Did I miss something when I was learning c++, and the both solutions are OK? Maybe this is caused by the way c++ is interpreted by Arduino? As I said I didn't see it in action, but I don't know why my client would lay about something he wants to work properly. At least it should cause problem during compilation (verification in Arduino IDE)

Upvotes: 0

Views: 394

Answers (1)

Mike Seymour
Mike Seymour

Reputation: 254691

The first converts the function into a function pointer, and tests whether that pointer is non-null. It always is, since every function has a non-null address, so it will always doSomething.

So the code will compile, and might appear to "work" if the condition is usually true; but it might go wrong when the condition is false but the program carries on to doSomething anyway.

Upvotes: 5

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