Hi,Ross,
I'm doubting this piece of code works correctly.
void BasicTaskScheduler0::triggerEvent(EventTriggerId eventTriggerId,
void* clientData) {
// First, record the "clientData":if (eventTriggerId == fLastUsedTriggerMask) { // common-case optimization: fTriggeredEventClientDatas[*eventTriggerId*] = clientData; // here not use *fLastUsedTriggerNum*???
} ... }
? 2010-12-11 14:19, Ross Finlayson ??:
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 callTaskScheduler:: 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.
-- *P.J.*
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