Re: ExtAudioFileRead Crash
Re: ExtAudioFileRead Crash
- Subject: Re: ExtAudioFileRead Crash
- From: Jean-Daniel Dupas <email@hidden>
- Date: Sun, 11 Oct 2009 22:55:33 +0200
Le 11 oct. 2009 à 22:25, Peter Castine a écrit :
On 11-Oct-2009, at 19:32, Jean-Daniel Dupas wrote:
It look like that this is your app which spawn additional threads.
On Leopard the app spawns *one* audio thread, and one audio thread
only.
It is the same app on Leopard and Snow Leopard.
I can see that multiple audio threads are running in the crash log.
But I'm not doing anything to spawn more threads.
Since Snow Leopard advertises how Grand Central Dispatch is
automatically multi-threading apps without developer intervention,
my question was basically if this will also instantiate multiple
threads on an API that is documented not to be thread-safe. If this
is indeed the case, what is the most efficient way to avoid the
problem?
On Snow Leopard, GCD thread are worker threads not plain pthreads. The
first symbol in the thread stack is start_wqthread and you always got
a bunch of dispatch_xxx symbols at the bottom of the stack trace.
In your crash log, the first two symbols on the trace are thread_start
and _pthread_start immediately follow by WorkerThreadStartFunc (which
is a function of your application).
This is obviously the result of a pthread_create call passing the
WorkerThreadStartFunc as third argument, not a GCD thread.
Maybe there is something on Leopard which prevent creation of
multithreads that does not works on Snow Leopard, but I recommend you
to check your thread creation code (putting a printf will allow a
quick check).
On 11-Oct-2009, at 18:38, tahome izwah wrote:
From the topmost call to CrashIfClientProvidedBogusAudioBufferList
() I
would surmise that there is something wrong with the ABL you're
providing. Are you sure that its format is matching the data you're
expecting?
Yes, I see this. Believe me, I have checked the thread prep code.
Again: on Leopard I do *not* get this crash. It occurs only on Snow
Leopard.
Maybe this is a Snow Leopard question rather than a CoreAudio one,
but I would have thought that other people using CoreAudio would be
getting burned if the OS 10.6 multi-threading is clobbering
ExtAudioFileRead.
-- P.
-- Jean-Daniel
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