NULL is OK, both for passing and for returning.

Parameter points to an array of items.

Generics and defining elements of containers and arrays.

Parameter for input. Default is transfer none.

The callback is valid only during the call to the method.

Exposed in C code, not necessarily available in other languages.

Free data after the code is done.

Don't free data after the code is done.

Override the parsed C type with given type.