# Annotation Glossary

### N

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 callee must allocate storage.

### T

transfer full

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