GetDesktopWindow

GetDesktopWindow is a function in the Windows API that retrieves a handle to the desktop window. The desktop window is a special top-level window that covers the entire screen and serves as the root of the top-level window hierarchy. The function returns an HWND that can be used with other Windows API calls that require a window handle.

Prototype: HWND GetDesktopWindow(void); The function takes no parameters and returns an HWND identifying the desktop window.

Use and behavior: The handle returned by GetDesktopWindow can be passed to functions that expect an HWND, such as GetWindowDC or GetDC to obtain a device context for the entire screen, or to various window enumeration and measurement APIs like EnumWindows and GetWindowRect. In practice, it is commonly used to obtain a device context for drawing, screen capture, or analysis tasks that operate on the full virtual screen.

Remarks: The desktop window is a system-provided window and acts as the base of the desktop’s UI. It is not treated as a regular interactive application window. Using GetDC(GetDesktopWindow()) or GetWindowDC(GetDesktopWindow()) yields a device context for the entire screen, which can be used for low-level graphics tasks such as BitBlt operations for screen captures.

See also: GetDC, GetWindowDC, ReleaseDC, EnumWindows.