David Parra has a suggestion for PHP developers out there - it might be beneficial to learn some C so you know what's going on.

I think most of the people using PHP wonder from time to time about particular behavior of the language. [...] But lately I stumbled over a nice one. It looked like a bug in PHP, but turns out to be an interesting, curious, part of the C-language.

He gives an example of a case where an error message (as a result of E_ALL error reporting) shows evaluation of certain variables in a different order than anticipated. As it turns out, the difference was in the order of the parameters in the C code of PHP (different on SPARC versus x86 systems).