WM_MOUSEMOVE
fwKeys = wParam; /* key flags */
xPos = LOWORD(lParam); /* horizontal position of cursor */
yPos = HIWORD(lParam); /* vertical position of cursor */The WM_MOUSEMOVE message is sent to a window when the mouse cursor moves. If the mouse is not captured, the message goes to the window beneath the cursor. Otherwise, the message goes to the window that has captured the mouse.
fwKeys
Value of wParam. Indicates whether various virtual keys are down. This parameter can be any combination of the following values:
| Value | Description |
| MK_CONTROL | Set if CTRL key is down. |
| MK_LBUTTON | Set if left button is down. |
| MK_MBUTTON | Set if middle button is down. |
| MK_RBUTTON | Set if right button is down. |
| MK_SHIFT | Set if SHIFT key is down. |
xPos
Value of the low-order word of lParam. Specifies the x-coordinate of the cursor, as a screen coordinate.
yPos
Value of the high-order word of lParam. Specifies the y-coordinate of the cursor, as a screen coordinate.
An application should return zero if it processes this message.
The MAKEPOINT macro can be used to convert the lParam parameter to a POINT structure.