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Parameters
hWnd
Identifies the window whose window procedure is to receive the message. Two values have special meanings:
Value Meaning
HWND_BROADCAST The message is posted to all top-level windows in the system, including disabled or invisible unowned windows, overlapped windows, and pop-up windows. The message is not posted to child windows.
NULL The function behaves like a call to PostThreadMessage with the dwThreadId parameter set to the identifier of the current thread.
Msg
Specifies the message to be posted.
wParam
Specifies additional message-specific information.
lParam
Specifies additional message-specific information.