PHP array to char **

Hi, I'm working on some improvements to the pgsql extension and I would like to know how to convert a zval* that points to a PHP array to a char** that I can pass to the pgsql API functions. The API function takes const char** so it will not modify the string, but the string must exist for the duration of the API call... I've been looking at other code that does similar things, but I can't help wondering if there is a simple, straightforward way of doing it? Cheers, Chris