AutoCAD Land Desktop

[#1]

I want to clear undo history when i undo one time.How can i do it?

I search on web and find this solution but it doesn't work.I use AcEditorReactor to capture first undo and when undo end i call this cammand:

acedCommand( RTSTR, "._UNDO", RTSTR, "_CONTROL", RTSTR, "_NONE", RTSTR, "._UNDO", RTSTR, "_ALL", 0 );

Thanks

[#2]

Can you elaborate on your need to "...clear undo history when i undo one time..." please?