Node:Predefined Aux-Item Types, Next:Client-Specific Aux-Item Types, Previous:Aux-Item Inheritance, Up:The Aux-Item List
Predefined Aux-Item types are part of Protocol A, and clients should support all of them. As with other parts of the protocol, changes to these definitions will be made backwards-compatible, if possible.
Creation and deletion of items with a predefined type can cause arbitrarily complex and wondrous behavior in the server. Furthermore, the server may place constraints on the items with regard to content, flags, who can create them, to what objects they can be attached and so forth. The server may also silently enforce specific values for any field of an item, regardless of what the client requests.
All items with tags in the range 1-9999 and 30000 and up are considered
predefined. If a client attempts to create an item with a tag in this
range, but the server has no idea what that tag means, the server will
return an error (illegal-aux-item).
Some items with tags in the range 10000-19999 are also predefined. They are items that initially were reserved for private use for a specific client, but where it was later discovered that the tag was generally useful. They should ideally have been assigned a number in the 1-9999 range from the beginning, but if they already have a widespread use they can be redefined to be predefined. Such redefinition will always be made in cooperation with the client writer.
See Aux-Item Types, for the complete list of predefined Aux-Item types.