# In GameMaker how to check if instance is a given object?

Let's say, I have three objects: obj_square, obj_circle and obj_triangle.

Instances of all three types of objects exists in the room and call the same script: scr_test.

Inside of this script, how can I check instance of which object is calling it?

Pseudocode:

if(self is instanceof(obj_circle))
{
// do stuff
}


object_index
if(object_index == obj_square) {