A LispWorks client can set up an advise loop across a conversation using dde-advise-start, which takes a conversation (or a service designator/ topic designator pair in the case of an automatically managed conversation using dde-advise-start*), an item , and a key as its main arguments. The key argument defaults to the conversation name, and can be used to distinguish between multiple advise loops established on the same service/topic/item group.
Whenever the data monitored by the advise loop changes, a function is called to inform the client. By default this function is the generic function dde-client-advise-data. You can add methods to dde-client-advise-data specialized on the key or the client conversation class. Alternatively, you can supply a different function in the call to dde-advise-start.
Note: a DDE advise loop is not a loop in the program source code. In particular it should not be confused with the "event loop" which is a loop in source code that processes low level events.
LispWorks User Guide and Reference Manual - 21 Dec 2011