Tk_CreateWindow(3) Tk (4.2) Tk_CreateWindow(3)
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NAME
Tk_CreateWindow, Tk_CreateWindowFromPath, Tk_DestroyWindow,
Tk_MakeWindowExist - create or delete window
SYNOPSIS
#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
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
children of the same
parent.
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
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Tk_CreateWindow(3) Tk (4.2) Tk_CreateWindow(3)
screen.
Tk_Window tkwin (in) Token for window.
char *pathName (in) Name of new window,
specified as path
name within
application (e.g.
.a.b.c).
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DESCRIPTION
The procedures Tk_CreateWindow 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. 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
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Tk_CreateWindow(3) Tk (4.2) Tk_CreateWindow(3)
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
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