GetWindowTextW function (winuser.h)

Makale
02/09/2023

Copies the text of the specified window's title bar (if it has one) into a buffer. If the specified window is a control, the text of the control is copied. However, GetWindowText cannot retrieve the text of a control in another application.

Syntax

int GetWindowTextW(
  [in]  HWND   hWnd,
  [out] LPWSTR lpString,
  [in]  int    nMaxCount
);

Parameters

[in] hWnd

Type: HWND

A handle to the window or control containing the text.

[out] lpString

Type: LPTSTR

The buffer that will receive the text. If the string is as long or longer than the buffer, the string is truncated and terminated with a null character.

[in] nMaxCount

Type: int

The maximum number of characters to copy to the buffer, including the null character. If the text exceeds this limit, it is truncated.

Return value

Type: int

If the function succeeds, the return value is the length, in characters, of the copied string, not including the terminating null character. If the window has no title bar or text, if the title bar is empty, or if the window or control handle is invalid, the return value is zero. To get extended error information, call GetLastError.

This function cannot retrieve the text of an edit control in another application.

Remarks

If the target window is owned by the current process, GetWindowText causes a WM_GETTEXT message to be sent to the specified window or control. If the target window is owned by another process and has a caption, GetWindowText retrieves the window caption text. If the window does not have a caption, the return value is a null string. This behavior is by design. It allows applications to call GetWindowText without becoming unresponsive if the process that owns the target window is not responding. However, if the target window is not responding and it belongs to the calling application, GetWindowText will cause the calling application to become unresponsive.

To retrieve the text of a control in another process, send a WM_GETTEXT message directly instead of calling GetWindowText.

Examples

For an example, see Sending a Message.

Note

The winuser.h header defines GetWindowText 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.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	winuser.h (include Windows.h)
Library	User32.lib
DLL	User32.dll
API set	ext-ms-win-ntuser-window-l1-1-4 (introduced in Windows 10, version 10.0.14393)

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