access to $this->myvar from C

Howdy folks, I'm writing a C wrapper function to php for my needs, and was wondering how I would go about getting access to a class variable. Here is what I have (for example) class my_class { var $mytest; function my_test() { myc_wrapper($foo); echo $this->mytest; } } from myc_wrapper, how can I set the value of this->mytest. I know I could just pass a variable to myc_wrapper, but I have a bunch of variables I have to pass back from myc_wrapper, and I don't want to use an array. I have read the docs on the "PHP Development" section of the on-line manual, but it wasn't very complete and seems out of date. Thanks Walt