# Annotation Glossary

### 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.

constructor

  This symbol is a constructor, not a static method.

### D

default

  Default parameter value (for in case the shadows-to function has less parameters).

destroy

  This parameter is a 'destroy_data', for callbacks.

### E

element-type

  Generics and defining elements of containers and arrays.

### I

in

  Parameter for input. Default is transfer none.

inout

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

### N

not nullable

  NULL must not be passed as the value in, out, in-out; or as a return value.

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 callee-allocates

  Out parameter, where caller must allocate storage.

out caller-allocates

  Out parameter, where caller must allocate storage.

### R

rename-to

  Rename the original symbol's name to SYMBOL.

### S

scope async

  The callback is valid until first called.

skip

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

### T

transfer container

  Free data container after the code is done.

transfer full

  Free data after the code is done.

transfer none

  Don't free data after the code is done.

type

  Override the parsed C type with given type.