I'm not sure that I would call PHP4 objects object oriented, as I remember it, it was all such a huge hack (down to being able to return null from a constructor). I only had to maintain some code like that at the tail end of PHP4's life, so I never found out whether that was how OOP was done in PHP4, or if it was a hack to simulate OOP in a language that didn't support it.
I'm not sure that I would call PHP4 objects object oriented, as I remember it, it was all such a huge hack (down to being able to return null from a constructor). I only had to maintain some code like that at the tail end of PHP4's life, so I never found out whether that was how OOP was done in PHP4, or if it was a hack to simulate OOP in a language that didn't support it.