[squeak-dev] Re: How can I listen to my app?

Chris Muller asqueaker at gmail.com
Fri Sep 12 15:44:03 UTC 2014


On Thu, Sep 11, 2014 at 6:38 PM, David T. Lewis <lewis at mail.msen.com> wrote:
> On Thu, Sep 11, 2014 at 02:47:55PM -0500, Chris Muller wrote:
>>
>> On Thu, Sep 11, 2014 at 2:42 PM, Chris Muller <asqueaker at gmail.com> wrote:
>> > I've decided I want to get a feel for what my app is doing and at what
>> > rate by, literally, listening to it.  I want to put in some brief
>> > beeps into strategic locations.
>> >
>> > But sound is an area where I have exactly zero experience.  I want the
>> > sounds to play but with minimal impact on the running program; i.e.,
>> > I'm willing to make the beeps very short, but even a 10ms beep (would
>> > I even be able to hear that?) would slow the program down.
>> >
>> > And yet, if I tried to play them in the background, they will not be
>> > in-sync with with the real-time state of the app.  I suppose another
>> > option would be to record the events I'm interested in and their time
>> > and play them back later, but I'm more interested in the *real-time*
>> > state.
>> >
>> > Finally, how can I play any sound at all with Squeak and Cog on Linux?
>> >  When I try some of the demo sounds on FMSound, there is no sound and
>> > I see this message in the console:
>> >
>> >     sound: /dev/dsp: No such file or directory
>> >
>> > Of course, no other apps on this machine have any trouble playing
>> > sounds, so is something simply pointing in the wrong place?
>>
>> squeak -help reports:
>>
>> Available drivers:
>>   vm-sound-null
>>   vm-sound-ALSA
>>   vm-sound-OSS
>>
>> But when I try:
>>
>>    squeak -vm sound=ALSA my.image
>>
>> and try to play a sound I get this on the console:
>>
>>    sound_Start(default)
>>    soundStart: snd_add_pcm_handler: Function not implemented
>>
>
> Sound works fine on my trusty SuSE box, but not at all on my user-friendly
> but generally untrustworthy Ubuntu laptop. What kind of system are you using?

I'm using one of the most popular Linux distros, Ubuntu.

I tried the -vm-sound-alsa switch to the vm (instead of -vm
sound=ALSA) but the same message is produced on the console when I try
to "FMSound pluckedElecBass play".

   sound_Start(default)
   soundStart: snd_add_pcm_handler: Function not implemented

Does this mean that Cog does not support sound?  Using "-vm sound=OSS"....
.....
WAIT!!!
....
Success!!!

I managed to get a sound out of Cog by:

  1) copying so.vm-sound-pulse from my interpreter VM lib directory to
Cog's lib directory
  2) renaming so.vm-sound-pulse to vm-sound-pulse
  3) setting execute permissions on vm-sound-pulse

With that, I can actually get sound out of Squeak..

And, now, when I do squeak -help, "vm-sound-pulse" is now listed.

Eliot, do you think we could eventually include this driver in your
Cog releases?

> Sound systems have been changing on Linux distributions, and I suspect that
> we may be falling behind in our support for this.
>
> Dave
>
>


More information about the Squeak-dev mailing list