PHP instanceof - return TRUE only for children

Question

I have two classes, A and B. B extends class A.

If I execute instance of A on an instance of B, it returns TRUE.

How can this be avoided?

This is exactly how it should work. Use 'instanceOf B' otherwise. — adhominem, Aug 25 '14 at 14:34
http://stackoverflow.com/questions/16688655/check-if-a-object-is-a-instance-of-a-class-but-not-a-instance-of-a-subclass — sebbo, Aug 25 '14 at 14:35

score 5 · Accepted Answer · answered Aug 25 '14 at 14:36

5

This is how instanceof works, and correctly so: if B inherits from A, it is also of type A.

However, you can check the precise class by using get_class() instead:

if (get_class($b_instance) == 'A') {
    // Not true
}

answered Aug 25 '14 at 14:36

ljacqu

score 1 · Answer 2 · answered Aug 25 '14 at 14:37

1

You need to check class by get_class function

if( get_class($Binst) == 'A' ) {
}

answered Aug 25 '14 at 14:37

Dmitry Bezik

score 1 · Answer 3 · answered Aug 25 '14 at 14:37

You may want to know the Class name of an object.

Try to use get_class($Object).

Example:

$objA = new A(); $objB = new B();

get_class($objA) will return "A".

and

get_class($objB) will return "B".

Then if you use

if (get_class($objB) == "A") { echo "Its a A"; }

score 1 · Answer 4 · answered Aug 25 '14 at 15:30

1

Use is_subclass_of() function: is_subclass_of($b, 'A')

answered Aug 25 '14 at 15:30

Marek

4 Answers4