Help Calling PHP_FUNCTION's from C ( inside PHP extension's function)

Hi, Consider two *PHP* extension A and B. Extension A exports a PHP_FUNCTION to userspace.. Let s call it Afunc(). Extension B exports a PHP_FUNCTION to userspace.. Let s call it Bfunc(). Now, Is there any way to use Afunc1() inside the body of Bfunc()? I don't want to call back to userspace. I want to call the PHP_FUNCTION of one extension in some other extension's C function. PHP_FUNCTION internally expands by a macro to C prototype. Am not getting a proper idea in calling them by passing arguments and getting values returned. I have been trying hard in this regard. Please help me in this.