This function is
EXPERIMENTAL. That means, that the behaviour of this
function, the function name, in concreto ANYTHING documented here can
change in a future release of this package WITHOUT NOTICE. Be warned, and
use this function at your own risk.
This reads the bytecodes from PHP for an existing function, and writes them to the
open file handle. Order is not important, (eg. if function b uses function a, and you
compile it like the example below, it will work perfectly OK)