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

On Tue, Feb 15, 2011 at 11:36:07AM -0600, Jack O'Quin wrote:
> On Tue, Feb 15, 2011 at 11:21 AM, Paul Davis <[hidden]> wrote:
> 
> > this is true EVEN IF the client registered a buffer size callback. why
> > so? despite the suggestion in the API docs for the buffer size
> > callback, existing implementations do NOT guarantee to call the
> > client's buffer size callback from within jack_activate(). this means
> > that there is no reliable way for a client to know the port buffer
> > size before its first process callback. the buffer size callback will
> > notify it of later changes to the size, but not the initial size when
> > it gets its first process() call.
> 
> Perhaps a stupid question: why not ensure the buffer size callback
> *is* invoked before the first process callback?
> 
> Is that because it cannot be called in the realtime thread?

how would you detect that its invoked ?
jack-svn is invoking bufsize callback during jack_activate()
there is no way, to be sure this happens.

so currently, one needs to allocate everything. then the bufsize cb will
come, and results in reallocations. the old signature of the bufsize cb
also does not allow determining the size of the midi port buffers.

the new functionname allows us do detect whether it will be called via
weak linking. we are basically solving 2 problems at once.

does it make sense to you now ?

> -- 
>  joq
> 
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-- 
torben Hohn

1297792161.26637_0.ltw:2,a <20110215174904.GL3055 at siel dot b>