Re: [Jack-Devel] buffer size callback, revisit

Ok, my bad... I was reading the jack.h header from JACK 1.9.6, it seems
to differ from the one at jackaudio.org. Probably just a
copy/paste-thing. After the paragraph you mentioned there is another one
in that header file:

> All "notification events" are received in a seperated non RT thread,
> the code in the supplied function does not need to be
> suitable for real-time execution.

I will just stop reading that header :-).

Cheers,

Arne

On 16.02.2011 16:21, Paul Davis wrote:
> On Wed, Feb 16, 2011 at 10:12 AM, Arne Jacobs <[hidden]> wrote:
>> On a sidenote:
>>
>> The JACK API documentation states for the buffer size callback, that it
>> is called in a "separate non RT thread", i.e., not in the process
>> thread. Which sounds to me that the process callback and the buffer size
>> callback can run in parallel.
> 
> where are you reading this? the docs at jackaudio.org state:
> 
>    Tell JACK to call bufsize_callback whenever the size of the the
> buffer that will be passed to the
>    process_callback is about to change. Clients that depend on knowing
> the buffer size must
>    supply a bufsize_callback before activating themselves.
> 
>> Is this really the case? It means you'd have to allocate new buffers and
>> then somehow send those to the process thread in a lock-free way...?
>> What if the process callback has already been called with the new buffer
>> size, while the other thread is still reallocating the buffers?
> 
> this sounds like an artifact of jack2 calling everything (?) but the
> process callback from a 2nd non-RT client thread. if it does this,
> then its wrong, in the sense that as you noted, its unworkable. buffer
> size changes and the process callback MUST be synchronous, i think.

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