IDL 4.2 · §8 (Building Block)

Annotations

Annotations attach metadata that drives wire behaviour and code generation: @key (instance identity), @final/@appendable/@mutable (extensibility), @optional, @id, @default and the full standardised XTypes set.

Example

@mutable
struct DeviceState {
  @key   @id(1) string<32> serial;
  @optional      double    temperature;
  @default(0)    long      error_code;
};

ZeroDDS support

OMG IDL 4.2 section	§8 (Building Block)
Implementation	`idl-rust/src/annotations.rs`
Tests	`annotations.rs`
Status	✓ RC3 — parsed, validated and code-generated across all target languages.

See also: IDL construct coverage · idl-4.2 audit · OMG IDL 4.2 spec