libtk/doc/CrtWindow.3

#include <tk.h>
Tk_Window
Tk_CreateWindow(interp, parent, name, topLevScreen)
Tk_Window
Tk_CreateWindowFromPath(interp, tkwin, pathName, topLevScreen)
Tk_DestroyWindow(tkwin)
Tk_MakeWindowExist(tkwin)
 ARGUMENTS
.AS Tcl_Interp *topLevScreen
.AP Tcl_Interp *interp out
Tcl interpreter to use for error reporting. If no error occurs,
then *interp isn't modified.
.AP Tk_Window parent in
Token for the window that is to serve as the logical parent of
the new window.
.AP char *name in
Name to use for this window. Must be unique among all children of
the same parent.
.AP char *topLevScreen in
Has same format as screenName. If NULL, then new window is
created 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.
.AP Tk_Window tkwin in
Token for window.
.AP char *pathName in
Name of new window, specified as path name within application
(e.g. .a.b.c).
E
 DESCRIPTION

The procedures Tk_CreateWindow
.VS
and Tk_CreateWindowFromPath
are used to create new windows for
use in Tk-based applications. Each of the procedures 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 successfully, 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.
.VE
An internal window is an interior window of a Tk application, 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 existing main
window. Examples of top-level windows are pop-up menus and dialog boxes.

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 assumption, 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 windows. 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_CreateWindow and allows
both top-level and internal windows to be created, depending on
the value of topLevScreen. In calls to Tk_CreateWindowFromPath,
as in calls to Tk_CreateWindow, the parent of the new window
must exist at the time of the call, but the new window must not
already exist.

The window creation procedures don't
actually issue the command to X to create a window.
Instead, they create a local data structure associated with
the window and defer the creation of the X window.
The window 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 window.

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 associated with it, including any event handlers
created with Tk_CreateEventHandler. In addition,
Tk_DestroyWindow will delete any children of tkwin
recursively (where children are defined in the Tk sense, consisting
of all windows that were created with the given window as parent).
If tkwin was created by Tk_CreateInternalWindow 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 instantiate the window given by tkwin.

 KEYWORDS
create, deferred creation, destroy, display, internal window,
screen, top-level window, window