Here we will described the functions that do not fit into any of the above categories and are essentially housekeeping functions.
There is a predicate that returns a reference to the main window of a Tcl/Tk interpreter:
tk_main_window(+TclInterpreter, -TkWindow)
which given a reference to a Tcl interpreter Tclnterpreter, returns a reference to its main window in TkWindow.
The window reference can then be used in tk_destroy_window/1:
tk_destroy_window(+TkWindow)
which destroys the window or widget referenced by TkWindow and all of its sub-widgets.
The predicate tk_make_window_exist/1 also takes a window reference:
tk_make_window_exist(+TkWindow)
which causes the window referenced by TkWindow in the Tcl interpreter TclInterpreter to be immediately mapped to the display. This is useful because normally Tk delays displaying new information for a long as possible (waiting until the machine is idle, for example), but using this call causes Tk to display the window immediately.
There is a predicate for determining how many main windows, and hence Tcl/Tk interpreters (excluding simple Tcl interpreters), are currently in use:
tk_num_main_windows(-NumberOfWindows)
which returns an integer in the variable NumberOfWindows.