The generic function
is the default function called when an advise loop informs a client that the data monitored by the loop has changed. By default it does nothing, but it may be specialized on the object used as the key in dde-advise-start or dde-advise-start*, or on a client conversation class if the default
See Advise loops for information about DDE advise loops.
LispWorks User Guide and Reference Manual - 21 Dec 2011