| 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 freeze operation should finish before MCI returns control to the application. |
| MCI_DGV_FREEZE_AT | Specifies that the rc field of the data structure identified by lParam2 contains a valid rectangle. The rectangle specifies a region within the frame buffer that will have the lock mask bit for each pixel turned on. The specified pixels will not be updated until their lock mask bit is turned off. If this flag is not specified, the rectangle defaults to the entire frame buffer. This flag is supported only if MCI_GETDEVCAPS message returns TRUE for the MCI_DGV_GETDEVCAPS_CAN_LOCK flag. |
| MCI_DGV_FREEZE_OUTSIDE | Indicates the area outside the region specified for the MCI_DGV_FREEZE_AT flag is frozen. |
| LPMCI_DGV_FREEZE_PARMS lParam2 | Specifies a far pointer to a MCI_DGV_FREEZE_PARMS data structure. |
| Return Value | Returns zero if successful. Otherwise, it returns an MCI error code. |
| Comments | This message does not affect the presentation source. It might continue to generate images that are discarded. |
| See Also | MCI_UNFREEZE |