Re: [eclipse-clp-users] embedded ECLiPSe in C++, problems with post event

From: Gesche Gierse <gierse_at_...358...>
Date: Sun, 24 Mar 2013 18:46:36 +0100
On 03/22/2013 10:47 PM, Joachim Schimpf wrote:
> On 22/03/2013 18:47, Gesche Gierse wrote:
>> Hello,
>> I'm currently using ECLiPSe embedded in a C++ project and I'm facing
>> some problem with sending events from C++ to ECLiPSe.
>> The C++ project has various threads, some running continuous, others
>> only for some time. The ECLiPSe context is initialized within one of the
>> continuous threads.
>> However the ECLiPSe program I want to run needs to call an predicate
>> whenever the control-thread is running (this is one of the
>> none-continuous threads). So I post an event to the ECLiPSe context
>> every time the control-thread is running.
>> Everything compiles just fine, and for like a minute it will run the way
>> it should, but at some time I always get a "Bogus event queue
>> notification in next_posted_event()"-error.
>> So my question is, is this a threading problem? Does posting events not
>> work well, when used in a thread that is non-continuous?
> Yes, this is very likely a threading problem.  The current event posting
> mechanism is not designed for thread communication.
> Could you briefly explain a few more details about your architecture,
> so we can suggest an alternative solution:
> Does your ECLiPSe thread process jobs that it receives via these events?
> If yes, are these jobs then queued, or interrupt each other?
> Is the event simple, or are you passing any data (arguments, etc)
> along with the event notification?  Or is it just an abort-event?

The event is quite simple.
In general the C++ threads belong to a cycle: sense, think, act. Eclipse
should do the "think" part, so the event I'm passing simply tells
ECLiPSe, that it's the start of the "think"-phase, and therefore it can
read the sensor data which are up to date at that point (no arguments
needs to be passed). It's simply an timing thing.

I used a solution with event_after_every at first, but I would rather
like to sync it with the C++ threads.

Received on Sun Mar 24 2013 - 17:46:50 CET

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