| MCI_NOTIFY | Specifies that MCI should post the MM_MCINOTIFY message when this command completes. The window that receives this message is specified in the dwCallback field of the data structure identified by lParam2. |
| MCI_TEST | Queries the device to determine if it can execute the command. The device returns an error if it is incapable of executing the command. It returns no error if it can handle the command. MCI returns control to the application without executing the command. |
| MCI_WAIT | Specifies that the unfreeze operation should finish before MCI returns control to the application. |
| MCI_DGV_RECT | Indicates the rc field of the data structure identified by lParam2 contains a valid display rectangle. The rectangle specifies a region within the frame buffer whose pixels should have their lock mask bit turned off. Rectangular regions are specified as described for the MCI_PUT command. If omitted, the rectangle defaults to the entire frame buffer. By using a sequence of freeze and unfreeze commands with different rectangles, arbitrary patterns of lock mask bits may be described. |
| LPMCI_DGV_RECT_PARMS lParam2 | Specifies a far pointer to a MCI_DGV_RECT_PARMS data structure. |
| Return Value | Returns zero if successful. Otherwise, it returns an MCI error code. |
| See Also | MCI_FREEZE |