How precise is the timing clock in tcl? When using the [after] command, an interesting thing happens when you start using small values, you don't necessarily get the callback until later. This can cause problems if you are doing animation, like I am right now. 

Run on different WinXP SP2 computers:

Not so good.
  % set e [clock micro] ; after 5 {puts [expr [clock micro] - $e]}
  after#39
  16000


Now this is more like it!
  % set e [clock micro] ; after 5 {puts [expr [clock micro] - $e]}
  after#5914
  5055


Different machines will fail at different small values. I think this is because of the way the [after] command must be implemented on windows.  See this page: http://www.geisswerks.com/ryan/FAQS/timing.html


'''How to fix it?'''

I'm thinking to make a seperate thread use a better Win32 timing schedule command and call the main thread. I guess this is reimplementing the [after] command. Anyone have a better idea?