Tk_WindowId returns the X identifier for tkwin, or NULL if no X window has been created for tkwin yet.
Tk_Parent returns Tk's token for the logical parent of tkwin. The parent is the token that was specified when tkwin was created, or NULL for main windows.
Tk_Interp returns the Tcl interpreter associated with a tkwin or NULL if there is an error.
Tk_Display returns a pointer to the Xlib display structure corresponding to tkwin. Tk_DisplayName returns an ASCII string identifying tkwin's display. Tk_ScreenNumber returns the index of tkwin's screen among all the screens of tkwin's display. Tk_Screen returns a pointer to the Xlib structure corresponding to tkwin's screen. Tk_AlwaysShowSelection indicates whether text/entry widgets should always display their selection, regardless of window focus.
Tk_X, Tk_Y, Tk_Width, and Tk_Height return information about tkwin's location within its parent and its size. The location information refers to the upper-left pixel in the window, or its border if there is one. The width and height information refers to the interior size of the window, not including any border. Tk_Changes returns a pointer to a structure containing all of the above information plus a few other fields. Tk_Attributes returns a pointer to an XSetWindowAttributes structure describing all of the attributes of the tkwin's window, such as background pixmap, event mask, and so on (Tk keeps track of all this information as it is changed by the application). Note: it is essential that applications use Tk procedures like Tk_ResizeWindow instead of X procedures like XResizeWindow, so that Tk can keep its data structures up-to-date.
Tk_IsContainer returns a non-zero value if tkwin is a container, and that some other application may be embedding itself inside tkwin.
Tk_IsEmbedded returns a non-zero value if tkwin is not a free-standing window, but rather is embedded in some other application.
Tk_IsMapped returns a non-zero value if tkwin is mapped and zero if tkwin is not mapped.
Tk_IsTopLevel returns a non-zero value if tkwin is a top-level window (its X parent is the root window of the screen) and zero if tkwin is not a top-level window.
Tk_ReqWidth and Tk_ReqHeight return information about the window's requested size. These values correspond to the last call to Tk_GeometryRequest for tkwin.
Tk_MinReqWidth and Tk_MinReqHeight return information about the window's minimum requested size. These values correspond to the last call to Tk_SetMinimumRequestSize for tkwin.
Tk_InternalBorderLeft, Tk_InternalBorderRight, Tk_InternalBorderTop and Tk_InternalBorderBottom return the width of one side of the internal border that has been requested for tkwin, or 0 if no internal border was requested. The return value is simply the last value passed to Tk_SetInternalBorder or Tk_SetInternalBorderEx for tkwin.
Tk_Visual, Tk_Depth, and Tk_Colormap return information about the visual characteristics of a window. Tk_Visual returns the visual type for the window, Tk_Depth returns the number of bits per pixel, and Tk_Colormap returns the current colormap for the window. The visual characteristics are normally set from the defaults for the window's screen, but they may be overridden by calling Tk_SetWindowVisual.
Tk_NewWindowObj creates a new Tcl_Obj from the window.