In php how do we call (int) (array) (object) ? Where to find more info about those?

[Rhudabon]

I was aware of (int) and (array) but not (object) and probably others.I'm wondering a) what is the proper name of those "things"; and, b) where can we found more information about those? (I was unable to find (object) on php.net website.Thanks in advance,MEM