If the scheduler is waiting on select() (in BasicTaskScheduler.cpp) to kick-in and no network activity or alarm happen to awake the select() will the new mechanism provide a mean to exit the threading loop ?
Thanks GB |-----Original Message----- |From: live-devel-boun...@ns.live555.com [mailto:live-devel- |boun...@ns.live555.com] On Behalf Of Ross Finlayson |Sent: Saturday, December 11, 2010 1:19 |To: live-de...@ns.live555.com |Subject: [Live-devel] New TaskScheduler 'event trigger' mechanism, and |(much) improved "DeviceSource" | |One of the biggest problems that developers have had with this library is that |it has been difficult to define and handle new kinds of event - beyond the |file/socket I/O and delayed task events that we support by default. | |In particular, it has been difficult to implement input devices (such as |encoders) when we want to signal a new event (such as the availability of new |frame data) from an external thread. The 'watch variable' mechanism - |although it can be used - is not particular well-suited for this purpose. |Furthermore, the model code in "DeviceSource.cpp" has not been particular |helpful, because it doesn't really describe what to do to handle events that |are signaled from an external thread. | |To overcome this, I have now installed a new version (2010.12.11) of the |"LIVE555 Streaming Media" library that now includes a new 'event trigger' |mechanism for "TaskScheduler" (and its subclass, "BasicTaskScheduler"). | |Specifically, you can now - using the new function | TaskScheduler::createEventTrigger() |- register an event handler function, to be associated with a particular 'event |trigger id'. At some later time, you can call | TaskScheduler:: triggerEvent() |with this 'event trigger id' as parameter, and this will cause the event handler |function to get called (from within the event loop). | |For more details, see "UsageEnvironment/include/UsageEnvironment.hh" | |One nice feature of this mechanism is that - unlike other library routines - the |"triggerEvent()" function can be called from a separate thread. This makes it |easier to implement input device classes. | | |I have also updated (and, I hope, significantly improved) the model code in |"liveMedia/DeviceSource.cpp". This code describes how to implement an |input device class that uses the new 'event trigger' |mechanism (with the event possibly being signaled from an external thread). | |If you're implementing (or have already implemented) an input device class, |then I encourage you to take a look at the new "DeviceSource" |code - and perhaps use this as a model for your code. |-- | |Ross Finlayson |Live Networks, Inc. |http://www.live555.com/ |_______________________________________________ |live-devel mailing list |live-devel@lists.live555.com |http://lists.live555.com/mailman/listinfo/live-devel _______________________________________________ live-devel mailing list live-devel@lists.live555.com http://lists.live555.com/mailman/listinfo/live-devel
