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 interp->result.
Tk_GetNumMainWindows returns a count of the number of main windows currently open in the process.
KEYWORDSapplication, main window