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 interp->result.
Tk_GetNumMainWindows returns a count of the number of main windows currently open in the process.
Copyright © 1990 The Regents of the University of California. Copyright © 1994-1996 Sun Microsystems, Inc. Copyright © 1995-1997 Roger E. Critchlow Jr.