This section describes a light weight class library for creating Tcl/Tk applications. [5] It consists of a header file tcl++.h, and a main program All you need to do to create a Tcl/Tk application is write any application specific Tcl commands using the NEWCMD macro, link your code with the tclmain code, and then proceed to write the rest of your application as a Tcl script. The tclmain code uses argv[1] to get the name of a script to execute, so assuming that the executable image part of your application is called appl, you would start off your application script with

...Your Tcl/Tk code goes here...
then your script becomes the application, directly launchable from the shell.

EcoLab processes any pending TCL events prior to executing the C++ implementation method. This keeps the GUI lively. However, it may cause problems if TCL scripts depend on C++ state that may be changed by event processing. There is a boolean global variable processEvents, that disables the background even processing if set to false. TCL commands enableEventProcessing and disableEventProcessing can be used to set/clear this flag from the TCL interface.