During indexing, OnProgressUpdate will be called frequently with information about the progress of the indexing job. You can use this information to show the user a progress bar or other status indicator during indexing. To access this information, create a class based on DIndexJob that overrides OnProgressUpdate. Example: 

 class CMyIndexJob : public DIndexJob {
     public:
         virtual void OnProgressUpdate(dtsIndexProgressInfo& info) {
         // ... show the user the update info in a dialog box
         }
     };

DIndexJob Class