A
allow-none
NULL is OK, both for passing and for returning.
array
Parameter points to an array of items.
C
closure
This parameter is a 'user_data', for callbacks; many bindings can pass NULL here.
D
destroy
This parameter is a 'destroy_data', for callbacks.
E
element-type
Generics and defining elements of containers and arrays.
I
inout
Parameter for input and for returning results. Default is transfer full.
N
nullable
NULL may be passed as the value in, out, in-out; or as a return value.
O
optional
NULL may be passed instead of a pointer to a location.
out
Parameter for returning results. Default is transfer full.
out caller-allocates
Out parameter, where caller must allocate storage.
S
scope notified
The callback is valid until the GDestroyNotify argument is called.
skip
Exposed in C code, not necessarily available in other languages.
T
transfer full
Free data after the code is done.
transfer none
Don't free data after the code is done.