Apple

On May 3, 2006, at 10:46 AM, rohit dhamija wrote:

I am developing a device driver for my USB bulk device, using I/O kit framework (its a user-level framework) and wanted your inputs in the following issue:

My application, i.e. user-interface loads the framework which in turn communicates with the device and returns back the data.

I need to achieve synchronization when multiple instances of the applications are running. For example, when we run 2 instances of the application, then each application will load the framework seperately and therefore each will have its own process space.

If you haven't discovered this yet, I/O Kit generally enforces single-open semantics. In other words, only one client can open an interface to a device at a time. (Other clients will get back a kIOReturnExclusiveAccess error.)

There is a mechanism that allows multiple processes to arbitrate access to a USB device. That is documented at <http://developer.apple.com/documentation/DeviceDrivers/Conceptual/ClassicUSBDeviceArb.html>.

Also, there is another mailing list devoted to USB development on the Mac <http://lists.apple.com/usb>.

Regards,

--gc

____________________________________________________________________

Garth Cummings email@hidden

Sr. Software Engineer

Apple Developer Technical Support

http://developer.apple.com/technicalsupport

References:
	>Synchronization b/w multiple instances...Help gurus.. (From: "rohit dhamija" <email@hidden>)