(PHP 5 >= 5.0.3)
ReflectionParameter::isOptional — Checks if optional
Checks if the parameter is optional.
Diese Funktion hat keine Parameter.
TRUE if the parameter is optional, otherwise FALSE
Lets say you have method defined
function read_me( a,b,c=1,d,e=2,f=3){}
then reading argument "c" to be optional, it will actually give you false (or nothing at all). This is probably a bug that counts number of required arguments, assuming you have put all optional to the end.