PATHHardware Documentation > USB Devices > Mac OS USB DDK API Reference

Passing Messages To Another Driver

The USBDriverNotify function supports message passing between drivers.



 
OSStatus USBDriverNotify (

                     USBReference reference,

                     USBDriverMessage mesg,

                     UInt32 refcon,

                     USBDriverNotificationCallbackPtr callback);

--> reference: A USBReference for the recipient driver.
--> mesg: The message to pass to the recipient driver
--> refcon: General reference value passed the completion routine for use by the driver.
--> callback: A pointer to a callback function.

Drivers call the USBDriverNotify function with the USB reference of the recipient driver, a message, a refcon, and an optional pointer to a callback function. The USB Manager locates the recipient driver based on the supplied reference and passes the message on by calling the USBDeviceNotificationCallbackProc for recipient driver, if it has a notification proc. Possible message constants are:



 
kNotifyAddDevice = 0x00,

kNotifyRemoveDevice = 0x01,

kNotifyAddInterface = 0x02,

kNotifyRemoveInterface = 0x03,

kNotifyGetDeviceDescriptor = 0x04,

kNotifyGetInterfaceDescriptor = 0x05,

kNotifyGetNextDeviceByClass = 0x06,

kNotifyGetDriverConnectionID = 0x07,

kNotifyInstallDeviceNotification = 0x08,

kNotifyRemoveDeviceNotification = 0x09

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