SYNOPSIS
	string function_exists(string str, object ob)

DESCRIPTION
	Return the file name of the object that defines the function
	str in object ob. The returned value can be other than
	file_name(ob) if the function is defined in an inherited
	object. The returned name always begins with a '/' (absolute
	path). 0 is returned if the function was not defined.

SEE ALSO
	call_other(E)