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 and for returning results. Default is transfer full.
NULL may be passed as the value in, out, in-out; or as a return value.
Parameter for returning results. Default is transfer full.
The callback is valid until first called.
Free data container after the code is done.
Alias for transfer none, used for objects with floating refs.
Free data after the code is done.
Don't free data after the code is done.