获取鼠标点窗口句柄

/* The GetCursorPos function retrieves the cursor's position, in screen coordinates. */
BOOL GetCursorPos(
LPPOINT &point
);

/* The WindowFromPoint function retrieves a handle to the window that contains the specified point. */
HWND WindowFromPoint(
POINT point
);

/*The GetWindow function retrieves a handle to a window that has the specified relationship (Z-Order or owner) to the specified window. */
HWND GetWindow(
HWND hWnd,
UINT uCmd //通过把uCmd代码设置为GW_HWNDNEXT来获取兄弟窗口的句柄
);