The SetActiveWindow function activates a window. The window must be attached to the calling thread's message queue.
Syntax
HWND SetActiveWindow(
HWND hWnd
);
Parameters
- hWnd
-
[in] Handle to the top-level window to be activated.
Return Value
If the function succeeds, the return value is the handle to the window that was previously active.
If the function fails, the return value is NULL. To get extended error information, call GetLastError.
Remarks
The SetActiveWindow function activates a window, but not if the application is in the background. The window will be brought into the foreground (top of Z-Order) if its application is in the foreground when the system activates the window.
If the window identified by the
hWnd parameter was created by the calling thread, the active window status of the calling thread is set to
hWnd. Otherwise, the active window status of the calling thread is set to NULL.
By using the AttachThreadInput function, a thread can attach its input processing to another thread. This allows a thread to call SetActiveWindow to activate a window attached to another thread's message queue.
Function Information
| Minimum DLL Version | user32.dll |
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| Header | Declared in Winuser.h, include Windows.h |
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| Import library | User32.lib |
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| Minimum operating systems |
Windows 95, Windows NT 3.1 |
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See Also