function_exists - find the file containing a given function in an object

string function_exists( string str, object ob, int flag );

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 by an inherited object.

0 is returned if the function was not defined.

Note that function_exists() does not check shadows.

If flag is omitted or zero functions that cannot be called are not returned (e.g. the function is returned only if call_other(ob, str) would succeed). If the flag is nonzero, static and private functions are returned too.