Tk_CreateWindow(3) Tk Library Procedures Tk_CreateWindow(3)______________________________________________________________________________NAME
Tk_CreateWindow, Tk_CreateWindowFromPath, Tk_DestroyWindow, Tk_MakeWin‐
dowExist - create or delete window
Tk_CreateWindow(interp, parent, name, topLevScreen)
Tk_CreateWindowFromPath(interp, tkwin, pathName, topLevScreen)
Tcl_Interp *interp (out) Tcl interpreter to use for error
reporting. If no error occurs,
then *interp isn't modified.
Tk_Window parent (in) Token for the window that is to
serve as the logical parent of
the new window.
char *name (in) Name to use for this window.
Must be unique among all chil‐
dren of the same parent.
char *topLevScreen (in) Has same format as screenName.
If NULL, then new window is cre‐
ated as an internal window. If
non-NULL, new window is created
as a top-level window on screen
topLevScreen. If topLevScreen
is an empty string (``'') then
new window is created as top-
level window of parent's screen.
Tk_Window tkwin (in) Token for window.
char *pathName (in) Name of new window, specified as
path name within application
The procedures Tk_CreateWindow and Tk_CreateWindowFromPath are used to │
create new windows for use in Tk-based applications. Each of the pro‐ │
cedures returns a token that can be used to manipulate the window in │
other calls to the Tk library. If the window couldn't be created suc‐ │
cessfully, then NULL is returned and interp->result is modified to hold │
an error message. │
Tk supports two different kinds of windows: internal windows and top- │
level windows. An internal window is an interior window of a Tk appli‐
cation, such as a scrollbar or menu bar or button. A top-level window
is one that is created as a child of a screen's root window, rather
than as an interior window, but which is logically part of some exist‐
ing main window. Examples of top-level windows are pop-up menus and
New windows may be created by calling Tk_CreateWindow. If the
topLevScreen argument is NULL, then the new window will be an internal
window. If topLevScreen is non-NULL, then the new window will be a
top-level window: topLevScreen indicates the name of a screen and the
new window will be created as a child of the root window of
topLevScreen. In either case Tk will consider the new window to be the
logical child of parent: the new window's path name will reflect this
fact, options may be specified for the new window under this assump‐
tion, and so on. The only difference is that new X window for a top-
level window will not be a child of parent's X window. For example, a
pull-down menu's parent would be the button-like window used to invoke
it, which would in turn be a child of the menu bar window. A dialog
box might have the application's main window as its parent.
Tk_CreateWindowFromPath offers an alternate way of specifying new win‐
dows. In Tk_CreateWindowFromPath the new window is specified with a
token for any window in the target application (tkwin), plus a path
name for the new window. It produces the same effect as Tk_CreateWin‐
dow and allows both top-level and internal windows to be created,
depending on the value of topLevScreen. In calls to Tk_CreateWin‐
dowFromPath, as in calls to Tk_CreateWindow, the parent of the new win‐
dow must exist at the time of the call, but the new window must not
The window creation procedures don't actually issue the command to X to
create a window. Instead, they create a local data structure associ‐
ated with the window and defer the creation of the X window. The win‐
dow will actually be created by the first call to Tk_MapWindow.
Deferred window creation allows various aspects of the window (such as
its size, background color, etc.) to be modified after its creation
without incurring any overhead in the X server. When the window is
finally mapped all of the window attributes can be set while creating
The value returned by a window-creation procedure is not the X token
for the window (it can't be, since X hasn't been asked to create the
window yet). Instead, it is a token for Tk's local data structure for
the window. Most of the Tk library procedures take Tk_Window tokens,
rather than X identifiers. The actual X window identifier can be
retrieved from the local data structure using the Tk_WindowId macro;
see the manual entry for Tk_WindowId for details.
Tk_DestroyWindow deletes a window and all the data structures associ‐
ated with it, including any event handlers created with Tk_CreateEven‐
tHandler. In addition, Tk_DestroyWindow will delete any children of
tkwin recursively (where children are defined in the Tk sense, consist‐
ing of all windows that were created with the given window as parent).
If tkwin is an internal window, then event handlers interested in
destroy events are invoked immediately. If tkwin is a top-level or
main window, then the event handlers will be invoked later, after X has
seen the request and returned an event for it.
If a window has been created but hasn't been mapped, so no X window
exists, it is possible to force the creation of the X window by calling
Tk_MakeWindowExist. This procedure issues the X commands to instanti‐
ate the window given by tkwin.
create, deferred creation, destroy, display, internal window, screen,
top-level window, window
Tk 4.2 Tk_CreateWindow(3)