Peter,
To answer your specific questions:
1. CMD_UPDATE_4 is a MicroStation keyin command to update view 4. The source of this could vary wide and far from MicroStation to an MDL or VBA application, or even users through keyin, function keys, etc.
2. The ChangeTrackInfo structure/parameter contains a modifying process name. For a drag move operation the modifying application is CLIBRD where a move element application is TRANSFRM - for these simple element operations. Read that as I would not make decisions in the code based on thsi since the operation could also be performed by other application for different element types and products installed.
Public void ChangeTrackElementChanged
(
MSElementDescrP newDescr,
MSElementDescrP oldDescr,
ChangeTrackInfo const* info,
char * sSourceInfo
)
char strApp[TASK_ID_SIZE];
...
strcpy (strApp, mdlSystem_getMdlTaskID (mdlSystem_getMdlDescFromProcessNumber (info->processNumber)));
SAMPLE RESULTS
2013-04-17 13:09:45.865,19,ChangeTrack,CLIPBRD,Element Modify,3,Line,678,0,Default,mdlErrNo: 0
2013-04-17 13:19:15.715,24,ChangeTrack,TRANSFRM,Element Modify,3,Line,678,0,Default,mdlErrNo: 0
It would be more beneficial if we would take a step back and ask what type of problem you are trying to solve since better or more modern approaches may make accomplishing the end goal/objective easier.
HTH,
Bob