First, they didn't call the PHP standard library: the poster of the root comment we are replying to has stated they didn't use the Zend runtime or code.<p>The PHP standard library has a huge number of functions that are mostly useless permutations of one another. As opposed to, say, Erlang's meager but usable lists and string module, PHP has such high-level meta-randomness as stristr() (case-insensitive search), str_word_count(), and str_shuffle(). So if you were going to convert that directly to C++, there wouldn't necessarily be a direct replacement in strings.h. Therefore I'd guess they either have to reimplement all of those in PHP, and compile that to C++, or write them in C++. Furthermore, some of these functions have unusual quirks, so some kind of framework would be required I think.