GetActiveWindow function (winuser.h)

Retrieves the window handle to the active window attached to the calling thread's message queue.

Syntax

HWND GetActiveWindow();

Type: HWND

The return value is the handle to the active window attached to the calling thread's message queue. Otherwise, the return value is NULL.

To get the handle to the foreground window, you can use GetForegroundWindow.

To get the window handle to the active window in the message queue for another thread, use GetGUIThreadInfo.

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)