Last modified: July 23, 2011

Applies to: Outlook

Uniquely identifies a connection between an advise sink, an advise source, and MAPI.

Header file:


typedef struct
  ULONG cb;


Count of bytes in the ab member.


Array of bytes describing the notification key.

The Subscribe and Notify methods of IMAPISupport use the NOTIFKEY structure to generate notifications to the appropriate advise sink about the appropriate advise source.

Service providers generate notification keys when their Advise method is called and they want to call Subscribe to handle the notification registration and the subsequent sending of notifications. A notification key can be the entry identifier of the advise source or it can be any other identifying item such as a constant. For example, a message store provider might use the path of a folder as its notification key.

The notification key should work across multiple processes.

The scope requirements for a notification key resemble those for a long-term entry identifier. However, unlike an entry identifier, a notification key must be binary-comparable. Typically, a notification key includes a GUID value defined by the service provider followed by other provider-specific information unique to the object.

For a discussion of the use of the NOTIFKEY structure to manage the connections between the advise sinks and the objects that generate the notifications, see Supporting Event Notification.