The following table summarizes the messages that correspond to the required command messages an application can send to your device driver. Your device driver must support all of these command messages.
DRV_CLOSE MCI_CLOSE_DRIVER
Closes the device. MCI translates the MCI_CLOSE sent by an application into the MCI_CLOSE DRIVER and DRV_CLOSE messages it sends to your device driver.
DRV_OPEN MCI_OPEN_DRIVER
Initializes the device. MCI translates the MCI_OPEN message sent by an application into the DRV_OPEN and MCI_OPEN_DRIVER messages it sends to your device driver.
Obtains information about the capabilities of the device.
Obtains information from a device driver.
Returns status information from the device driver.