Re: [Discuss-gnuradio] how to implement synchronous source block correctly ?

[Artem Pisarenko]

Thank you for fast answer.

Martin Braun (CEL) wrote
> There's an overview of the scheduler:
> http://gnuradio.squarespace.com/blog/2013/9/15/explaining-the-gnu-radio-scheduler.html
> "Users", as you say, usually don't need more than this to write GNU
> Radio code, and most often don't need to know anything at all about it.

If I'm not user, but also I'm not developer, who am I then ? ;)
I reviewed this "developers-internal" document already and that's why I
intentionally mentioned user point of view.


Martin Braun (CEL) wrote
> You never use a throttle and a hardware clock in one flow graph (e.g.
> throttle + audio)

Does it means that I can use multiple synchronous blocks of same type ? I've
checked "audio source -> audio sink" and I get same underruns.


Martin Braun (CEL) wrote
> work() should never block. Sources are a bit of an exception, though...

I see audio sink doesn't consume CPU, so it blocks too ? Another exception
?..


Martin Braun (CEL) wrote
> - I'm pretty sure you've misunderstood the concept of a "sync block".
>   Refer to [1] for an introduction. It merely describes the ratio of
>   input and output rates. The opposite of a sync block is *not* an
>   'async' block.

No, it's just ambiguous terminology. How should we call blocks producing
output synchronously with some reference source ?


Martin Braun (CEL) wrote
> - The scheduler does all the work for you regarding calling of work().
>   You don't need to interrupt work(). Not sure what you're intentions
>   were with using stop().

My intention was to use non-timeout blocking calls (as supposed to be
correct) in work() with wait condition on some "stop" signal.


Martin Braun (CEL) wrote
> Writing blocks is one of the things we try and document as good as
> possible. The corresponding tutorial [1] has received a lot of feedback
> and has been continuously updated. It also discusses most of the
> questions you had earlier.

Due to lack of documentation, this tutorial was the only source and I
learned it from cover to cover. I mentioned only non-trivial issues which is
not discussed in it. So it's new feedback ;)



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