C, PHP interaction

Does anyone know how to write functions in C or C++ and then use them in PHP?

Thanks.

I wasnt aware that PHP was capable of such things. CGI can be used for this though.

I'm not sure whether or not there is a built-in feature that does this.
But since PHP is open-source, it may be possible to modify it in order to execute native C/C++

only thing I can think of is having PHP exec(ing) programs.

http://us3.php.net/exec

There are of course some issues you will have to work around yourself like piping certain things, etc.