A
NULL is OK, both for passing and for returning.
Parameter points to an array of items.
C
This parameter is a 'user_data', for callbacks; many bindings can pass NULL here.
N
NULL may be passed as the value in, out, in-out; or as a return value.
O
NULL may be passed instead of a pointer to a location.
Parameter for returning results. Default is transfer full.
Out parameter, where caller must allocate storage.
S
The callback is valid only during the call to the method.
Exposed in C code, not necessarily available in other languages.
T
Free data after the code is done.
Don't free data after the code is done.
Override the parsed C type with given type.