_ref and ref

_ref assigns an integer reference to objects added or found by a command. Later commands in the same request consume it through ref or a command-specific field such as src, dst, image_ref, or video_ref. A reference may represent several matched objects.

References must be declared before use, have the object type required by the consumer, and use IDs from 1 through 100000. Do not reuse an ID for another producer in the same request. References expire with the request; use an object’s _uniqueid or an application property to find it in a later request.

Omitting _ref creates no reference. Setting it does not itself request properties or binary output. In a reference-only Find command, returned: 0 can therefore accompany a nonempty match set; see Responses. A command using batch cannot also establish _ref.

For complete creation and traversal examples, see Transactions and references. See connect, is_connected_to, and AddConnection for consuming fields.