GetWindowTextLength

This function 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.

At a Glance

Header file:	Winuser.h
Windows CE versions:	1.0 and later

Syntax

int GetWindowTextLength( HWND hWnd);

Parameters

hWnd

Handle to the window or control.

Return Values

The length, in characters, of the text indicates success. Under certain conditions, this value may actually be greater than the length of the text. For more information, see the following Remarks section. Zero indicates that the window has no text. To get extended error information, 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 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.

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