# Annotation Glossary

### A

allow-none

  NULL is OK, both for passing and for returning.

### C

constructor

  This symbol is a constructor, not a static method.

### I

in

  Parameter for input. Default is transfer none.

### O

out

  Parameter for returning results. Default is transfer full.

### T

transfer floating

  Alias for transfer none, used for objects with floating refs.

transfer full

  Free data after the code is done.

transfer none

  Don't free data after the code is done.

### 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.