[CM] Re: snd jack playback mode bug

Tim Orford tim@orford.org
Tue, 02 Nov 2004 20:28:20 +0100

On Sun, Oct 31, 2004 at 06:16:15PM +0100, Kjetil Svalastog Matheussen wrote:
> > If you are running jack in Playback mode, snd 7.8 will
> > imediately segfault in mus_audio_read_buffers().
> > 
> > i assume that this is easily repeatable. I can provide
> > any additional information if needed.
> > 
> Yes, please provide some code that use mus_audio_read_buffers.
> I wrote the jack-code, but have never used mus_audio_read_buffers.

yes thanks for adding this v useful functionality!
I must apologise for the incorrect information regarding
mus_audio_read_buffers - that was indicated by gdb but appears to
be false. By adding printfs i beleive the segfault happens here:

static int sndjack_getnuminchannels(void){
  int lokke=0;
  const char **ports=jack_get_ports(sndjack_client,"alsa_pcm:capture_*","",0);

  while(ports[lokke]!=NULL){ ////// ****appears to crash here with lokke=0
  if(lokke<2) return 2;
  return lokke;

I'm using jack 9.8, but am still assuming that this segfault is
reproducable on any system when jack is started with '--playback'.
If others have no time or inclination to fix, i will gladly do so, but
am reluctant as i have little experience of jack coding or knowledge
of Snd.

Once again, thanks Kjetil for adding jack support, and regards to
Tim Orford