nf-winuser-gettopwindow.md

UID	NF:winuser.GetTopWindow
title	GetTopWindow function (winuser.h)
description	Examines the Z order of the child windows associated with the specified parent window and retrieves a handle to the child window at the top of the Z order.
helpviewer_keywords	GetTopWindow GetTopWindow function [Windows and Messages] _win32_GetTopWindow _win32_gettopwindow_cpp winmsg.gettopwindow winui._win32_gettopwindow winuser/GetTopWindow
old-location	winmsg\gettopwindow.htm
tech.root	winmsg
ms.assetid	VS|winui|~\winui\windowsuserinterface\windowing\windows\windowreference\windowfunctions\gettopwindow.htm
ms.date	12/05/2018
ms.keywords	GetTopWindow, GetTopWindow function [Windows and Messages], _win32_GetTopWindow, _win32_gettopwindow_cpp, winmsg.gettopwindow, winui._win32_gettopwindow, winuser/GetTopWindow
req.header	winuser.h
req.include-header	Windows.h
req.target-type	Windows
req.target-min-winverclnt	Windows 2000 Professional [desktop apps only]
req.target-min-winversvr	Windows 2000 Server [desktop apps only]
req.kmdf-ver
req.umdf-ver
req.ddi-compliance
req.unicode-ansi
req.idl
req.max-support
req.namespace
req.assembly
req.type-library
req.lib	User32.lib
req.dll	User32.dll
req.irql
targetos	Windows
req.typenames
req.redist
ms.custom	19H1
f1_keywords	GetTopWindow winuser/GetTopWindow
dev_langs	c++
topic_type	APIRef kbSyntax
api_type	DllExport
api_location	ext-ms-win-rtcore-ntuser-window-ext-l1-1-1.dll ext-ms-win-ntuser-window-l1-1-6.dll ext-ms-win-ntuser-window-l1-1-5.dll User32.dll API-MS-Win-NTUser-IE-Window-l1-1-0.dll ie_shims.dll API-MS-Win-RTCore-NTUser-Window-l1-1-0.dll minuser.dll Ext-MS-Win-RTCore-NTUser-Window-Ext-l1-1-0.dll
api_name	GetTopWindow
req.apiset	ext-ms-win-ntuser-window-l1-1-4 (introduced in Windows 10, version 10.0.14393)

GetTopWindow function

-description

Examines the Z order of the child windows associated with the specified parent window and retrieves a handle to the child window at the top of the Z order.

-parameters

-param hWnd [in, optional]

Type: HWND

A handle to the parent window whose child windows are to be examined. If this parameter is NULL, the function returns a handle to the window at the top of the Z order.

-returns

Type: HWND

If the function succeeds, the return value is a handle to the child window at the top of the Z order. If the specified window has no child windows, the return value is NULL. To get extended error information, use the GetLastError function. The function does not clear the last error information. To determine success or failure in case of NULL return value, clear the last error information by calling SetLastError function with 0 value, then call GetTopWindow. Function failure will be indicated by a return value of NULL and a GetLastError function result that is nonzero.

-see-also

Conceptual

GetNextWindow

GetWindow

Reference

Windows