# 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.

### 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.

### M

method

  This is a method

### 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 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.

scope call

  The callback is valid only during the call to the method.

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.

### U

Unstable

  Unstable interfaces are experimental or transitional. They are typically used to give outside developers early access to new or rapidly changing technology, or to provide an interim solution to a problem where a more general solution is anticipated. No claims are made about either source or binary compatibility from one minor release to the next. The Unstable interface level is a warning that these interfaces are subject to change without warning and should not be used in unbundled products. Given such caveats, customer impact need not be a factor when considering incompatible changes to an Unstable interface in a major or minor release. Nonetheless, when such changes are introduced, the changes should still be mentioned in the release notes for the affected release.

### V

virtual

  This is the invoker for a virtual method.