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NF:winuser.GetWindowTextLengthW

GetWindowTextLengthW function (winuser.h)

Retrieves the length, in characters, of the specified window's title bar text (if the window has a title bar). (Unicode)

GetWindowTextLength

GetWindowTextLength function [Windows and Messages]

GetWindowTextLengthW

_win32_GetWindowTextLength

_win32_getwindowtextlength_cpp

winmsg.getwindowtextlength

winui._win32_getwindowtextlength

winuser/GetWindowTextLength

winuser/GetWindowTextLengthW

winmsg\getwindowtextlength.htm

winmsg

VS|winui|~\winui\windowsuserinterface\windowing\windows\windowreference\windowfunctions\getwindowtextlength.htm

12/05/2018

GetWindowTextLength, GetWindowTextLength function [Windows and Messages], GetWindowTextLengthA, GetWindowTextLengthW, _win32_GetWindowTextLength, _win32_getwindowtextlength_cpp, winmsg.getwindowtextlength, winui._win32_getwindowtextlength, winuser/GetWindowTextLength, winuser/GetWindowTextLengthA, winuser/GetWindowTextLengthW

winuser.h

Windows.h

Windows

Windows 2000 Professional [desktop apps only]

Windows 2000 Server [desktop apps only]

GetWindowTextLengthW (Unicode) and GetWindowTextLengthA (ANSI)

User32.lib

User32.dll

Windows

19H1

GetWindowTextLengthW

winuser/GetWindowTextLengthW

c++

APIRef

kbSyntax

DllExport

User32.dll

Ext-MS-Win-NTUser-Window-l1-1-1.dll

Ext-MS-Win-NTUser-Window-l1-1-2.dll

ext-ms-win-ntuser-window-l1-1-3.dll

Ext-MS-Win-NTUser-Window-L1-1-0.dll

Ext-MS-Win-NTUser-Window-L1-1-4.dll

GetWindowTextLength

GetWindowTextLengthA

GetWindowTextLengthW

ext-ms-win-ntuser-window-l1-1-1 (introduced in Windows 8.1)

GetWindowTextLengthW function

-description

Retrieves the length, in characters, of the specified window's title bar text (if the window has a title bar). If the specified window is a control, the function retrieves the length of the text within the control. However, GetWindowTextLength cannot retrieve the length of the text of an edit control in another application.

-parameters

-param hWnd [in]

Type: HWND

A handle to the window or control.

-returns

Type: int

If the function succeeds, the return value is the length, in characters, of the text. Under certain conditions, this value might be greater than the length of the text (see Remarks).

If the window has no text, the return value is zero.

Function failure is indicated by a return value of zero and a GetLastError result that is nonzero.

Note

This function does not clear the most recent error information. To determine success or failure, clear the most recent error information by calling SetLastError with 0, then call GetLastError.

-remarks

If the target window is owned by the current process, GetWindowTextLength causes a WM_GETTEXTLENGTH message to be sent to the specified window or control.

Under certain conditions, the GetWindowTextLength function may return a value that is larger than the actual length of the text. This occurs with certain mixtures of ANSI and Unicode, and is due to the system allowing for the possible existence of double-byte character set (DBCS) characters within the text. The return value, however, will always be at least as large as the actual length of the text; you can thus always use it to guide buffer allocation. This behavior can occur when an application uses both ANSI functions and common dialogs, which use Unicode. It can also occur when an application uses the ANSI version of GetWindowTextLength with a window whose window procedure is Unicode, or the Unicode version of GetWindowTextLength with a window whose window procedure is ANSI. For more information on ANSI and ANSI functions, see Conventions for Function Prototypes.

To obtain the exact length of the text, use the WM_GETTEXT, LB_GETTEXT, or CB_GETLBTEXT messages, or the GetWindowText function.

Note

The winuser.h header defines GetWindowTextLength as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.