Tk_MainWindow, Tk_GetNumMainWindows - functions for query
ing main window information
Tcl_Interp *interp (in/out) Interpreter associated
with the application.
A main window is a special kind of toplevel window used as
the outermost window in an application.
If interp is associated with a Tk application then
Tk_MainWindow returns the application's main window. If
there is no Tk application associated with interp then
Tk_MainWindow returns NULL and leaves an error message in
Tk_GetNumMainWindows returns a count of the number of main
windows currently open in the process.
application, main window