Checking if an instance's class implements an interface?

Question

Given a class instance, is it possible to determine if it implements a particular interface? As far as I know, there isn\'t a built-in function to do this directly. What opt

Answer 1

Update

The is_a function is missing here as alternative.

I did some performance tests to check which of the stated ways is the most performant.

Results over 100k iterations

      instanceof [object] took   7.67 ms | +  0% | ..........
            is_a [object] took  12.30 ms | + 60% | ................
             is_a [class] took  17.43 ms | +127% | ......................
class_implements [object] took  28.37 ms | +270% | ....................................
       reflection [class] took  34.17 ms | +346% | ............................................

Added some dots to actually "feel" see the difference.

Generated by this: https://3v4l.org/8Cog7

Conclusion

In case you have an object to check, use instance of like mentioned in the accepted answer.

In case you have a class to check, use is_a.

Bonus

Given the case you want to instantiate a class based on an interface you require it to have, it is more preformant to use is_a. There is only one exception - when the constructor is empty.

Example: is_a(, , true);

It will return bool. The third parameter "allow_string" allows it to check class names without instantiating the class.