# Annotation Glossary

### A

allow-none

  NULL is OK, both for passing and for returning.

array

  Parameter points to an array of items.

### 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

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

out

  Parameter for returning results. Default is transfer full.

out caller-allocates

  Out parameter, where caller must allocate storage.

### S

scope async

  The callback is valid until first called.

skip

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

### T

transfer container

  The caller owns the data container, but not the data inside it.

transfer full

  The caller owns the data, and is responsible for free it.

transfer none

  The data is owned by the callee, which is responsible of freeing it.