At 12:38 -0800 5/3/03, Vivek Balasubramanyam wrote: There isn't a specific need to use wait queues over any other kind of synchronization, since only one thread is ever in the queue. But I do need to use something that will let this thread sleep until a separate thread sends a wakeup signal (when the buffer goes from empty to non-empty). I get the feeling you're barking up the wrong tree here. Specifically, if you have an I/O Kit driver that installs a character device, Mach primitives are probably too low-level. Instead, you should probably be using BSD primitives, such as "sleep" and "wakeup". Of course, to use these from within a I/O Kit driver, you have to manually acquire the appropriate BSD funnel. You can see all of this in the IOSerialBSDClient driver, which is Apple's code to shim from I/O Kit into a BSD character device. <http://www.opensource.apple.com/cgi-bin/registered/cvs/IOSerialFamily/IOSerialFamily.kmodproj/IOSerialBSDClient.cpp?rev=1.1.1.3&content-type=text/x-cvsweb-markup> [APSL account required] Another option might be to publish *two* nubs from your driver, the first one being the actual modem and the second being the monitoring device. I/O Kit will then match IOSerialBSDClient on top of each, and you can let it shim you into BSD. S+E -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Technical Support * Networking, Communications, Hardware _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.