The default queue callback routine handles notifications sent by SetupCommitFileQueue in a generic manner. By using the default routine, you get a ready-made user interface to create common setup dialog boxes. It is recommended that you use the default queue callback routine, both for ease of use, and to ensure a consistent appearance and behavior of dialog boxes generated during the installation.
The default callback routine requires a context structure for internal record keeping. In addition, the queue passes additional information relevant to the current notification in a set of parameters, Param1 and Param2.
For example, if the queue sends an SPFILENOTIFY_NEEDMEDIA notification to the default callback routine, Param1 points to a SOURCE_MEDIA structure that contains information about the media needed, and Param2 points to a character array that can receive new path information from the user.
The default callback routine uses this information to prompt the user to either insert the needed source media, specify a new path, skip copying the current file, or cancel the current operation. The default queue callback routine returns FILEOP_NEWPATH, FILEOP_DOIT , FILEOP_SKIP, or FILEOP_ABORT to the queue, depending on which action the user took.
For information on how the default queue callback routine handles each queue notification, see File Queue Notifications.