# 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

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.

### S

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 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.

type

  Override the parsed C type with given type.

### V

virtual

  This is the invoker for a virtual method.