Application Note:   Sourcing scripts into production readout
                    atomatcally on startup.
					Ron Fox (fox at nscl dot msu dot edu)


Sometimes, users of the production readout software need to source a tcl script when
the program starts up.  This can be done using the extensibility of the Readout Gui.
    When the readout gui starts, it searches for a file named ReadoutCallouts.tcl  in 
~ and ~/experiments/current.  If found, this file is sourced prior to creating the 
GUI.  All instances of the file are sourced.
  The file can contain arbitrary initialization code (for example you could create a 
toplevel widget that contains user interface elements to extend the GUI provided by 
ReadoutGUI.  You can also define any of the following proc's to be called by the 
ReadoutGUI as follows:

OnStart    - Called when the readout program has been started.
OnBegin    - Called when the run is just about to start.  This proc
             Receives the run number as a parameter
OnEnd      - Called when the run has just ended.  This proc receives 
             the run number as a parameter.
OnPause    - Called when the run has just paused.  This proc receives
		 the run number as a parameter.
OnResume   - Called just prior to resuming a paused run.  This proc 
		 receives the run number as a parameter.

The script below is a sample ReadoutCallouts.tcl script that sources a TCL Script 
into a production readout program whenever it is started.



#---------------------- Script starts -----------------------------
package require ReadoutControl


proc OnStart {} {
    after 500
    set scriptfile "~/experiment/current/essentialinitialization.tcl"
    set f [open $scriptfile r]
    set contents [read $f]
    close $f
    ReadoutControl::SendCommand $contents
}
#-------------------- Script ends ----------------------------------