Applications use the MCI_GETDEVCAPS message to determine the capabilities of a device and its device driver. An application will supply a pointer to a MCI_GETDEVCAPS_PARMS data structure. This structure has the following fields:
typedef struct {
DWORDdwCallback;// Callback for MCI_NOTIFY
DWORDdwReturn;// Information returned to user
DWORDdwItem;// Flag specifying type of information
The dwReturn field of this data structure contains the information returned by your device driver. The MCI_GETDEVCAPS_ITEM flag sent by the application validates the dwItem field of this data structure. The contents of dwItem specify the type of information requested. The following constants are always defined for MCI_GETDEVCAPS:
| MCI Constant | Description |
| MCI_GETDEVCAPS_CAN_RECORD | Return TRUE if device has recording capabilities; false otherwise. Returning TRUE implies that the device driver also has stop and pause capabilities. |
| MCI_GETDEVCAPS_HAS_AUDIO | Return TRUE if the device has audio capabilities; FALSE otherwise. |
| MCI_GETDEVCAPS_HAS_VIDEO | Return TRUE if the device has video capabilities; FALSE otherwise. |
| MCI_GETDEVCAPS_USES_FILES | Return TRUE if the device driver uses files; FALSE otherwise. Returning TRUE implies the device driver is also a compound device. |
| MCI_GETDEVCAPS_COMPOUND_DEVICE | Return TRUE if the device driver uses device elements. |
| MCI_GETDEVCAPS_DEVICE_TYPE | Return the device driver type. |
| MCI_GETDEVCAPS_CAN_EJECT | Return TRUE if the device can eject the media; FALSE otherwise. |
| MCI_GETDEVCAPS_CAN_PLAY | Return TRUE if the device has playback capabilities; FALSE otherwise. Returning TRUE implies that the device driver also has stop and pause capabilities. |
| MCI_GETDEVCAPS_CAN_SAVE | Return TRUE if the device driver can save data; FALSE otherwise. |