This message informs the window that it is being destroyed. The DestroyWindow function sends the WM_DESTROY message to the window after removing the window from the screen. The WM_DESTROY message is sent to a parent window before any of its child windows are destroyed.
wParam
This parameter is not used.
lParam
This parameter is not used.
If the window being destroyed is part of the clipboard-viewer chain (set by using the SetClipboardViewer function), the window must remove itself from the clipboard viewer chain by processing the ChangeClipboardChain function before returning from the WM_DESTROY message.
ChangeClipboardChain, DestroyWindow, SetClipboardViewer