Parameter for returning results. Default is transfer full.

The callback is valid until first called.

NULL is ok, both for passing and for returning.

Parameter for input and for returning results. Default is transfer full.

This parameter is a 'user_data', for callbacks; many bindings can pass NULL here.

Don't free data after the code is done.

Parameter points to an array of items.

Parameter for input. Default is transfer none.

Free data after the code is done.

Typed errors. Similar to throws in Java.