Personal Communications Response

If Personal Communications can perform the DDE_UNADVISE, Personal Communications returns an ACK message containing positive status information to the client:
WM_DDE_ACK(wStatus, aItem)

If Personal Communications cannot perform the DDE_UNADVISE, Personal Communications returns an ACK message containing negative status information and one of the following return codes in the low-order byte of the wStatus word.

Return Code Explanation
1 Advise has not started yet.
9 A system error occurred.