About the Default Queue Callback Routine
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.
For information on custom queue callback routines, see Creating a Custom Queue Callback Routine.