[chuck-users] a little debugging help for frozen VM!

[Scott Hewitt]

Hi,

I have often wondered if this behaviour should be detected by the
compiler / VM and cause an error to occur

I have actually used this behaviour to illustrate a wider security
concern in a paper accepted to the upcoming ICMC

And that is a cool first ChucK problem Chris!!

On Fri, May 25, 2012 at 8:57 PM, Andrew Turley <aturley at acm.org> wrote:
> Your code never gets out of the first while-loop. Among other things,
> that means that you never make it to the pedEvent handler. I'm not
> entirely sure what you're trying to do, but I think you want something
> more like this:
>
> //begincode
>
> Machine.add("justa.ck");                        //class of frequency definitions
> Machine.add("pedestrianSender.ck");      //OSC sender of int values
>
> OscRecv receiver;                                //OSC receiver object
> 6449 => receiver.port;
> receiver.listen();
> receiver.event("weather/pedestrian, int") @=> OscEvent pedEvent;
>
> -1 => int b3base1;  //int to store a shred ID
> -1 => int b3base2;  //ditto
>
> 25 => int pedCount; //int to store pedCount sent via OSC
>
> while (pedEvent.nextMsg() != 0) {
>  pedEvent.getInt() => pedCount;
>
>  //if the pedCount is greater than 20 (a value which will be sent via
> OSC) and b3base1 is equal to -1, i.e. the shred isn't currently
> running,
>  //add both shreds to the VM and assign their shred ID to the b3base1
> and b3base2
>
>  if (pedCount > 20 && b3base1 == -1) {
>    Machine.add("b3base.ck") => b3base1;
>    Machine.add("b3base.ck") => b3base2;
>  }
>
>  else {
>
>    //if the pedCount is less than 20, remove both shreds from the VM
> and assign -1 to their value so that if the pedCount goes back above
> 20 they
>    //meet the conditional.
>
>    if (pedCount < 20 && b3base1 != -1) {
>      Machine.remove(b3base1);
>      Machine.remove(b3base2);
>      -1 => b3base1;
>      -1 => b3base2;
>    }
>  }
>
>  while( pedEvent.nextMsg() != 0) {
>    pedEvent.getInt() => pedCount;
>    2::second => now;
>  }
> }
>
> //endcode
>
> If you need to run through the loop once when you start then you could
> use a do-while-loop instead of a while-loop
> (http://chuck.cs.princeton.edu/doc/language/ctrl.html#while).
>
> andy
>
> On Fri, May 25, 2012 at 3:32 PM, [chriswicks] <crwicks at yahoo.com> wrote:
>> Hey, all.  I'm attempting to build something that shifts layers of ChucK
>> files based on OSC events, and I hit a snag really early on.  I'm a
>> relatively new programmer, so hopefully this isn't too stupid of a question,
>> but I've got an issue that freezes the virtual machine and doesn't play any
>> sound or send any OSC events.  Nothing happens..the VM shows that the shreds
>> are added, and then it just freezes and I have to force quit...it won't take
>> a --removeall or --kill command or anything.  Individually, each file works
>> as it should, aside from the file whose code I am including here.  I think I
>> may be missing a key concept as to the way Machine.add works and how it
>> assigns the value of the shred to an int, but I'm just not sure.  If anyone
>> can give me some direction here as to what might be happening I'd appreciate
>> it!  I've tried advancing time in various places, setting my initial
>> pedCount to various values, all to no avail.  Thanks very much, and please
>> let me know if this is unclear in any way.
>>
>> //begincode
>>
>> Machine.add("justa.ck");                        //class of frequency
>> definitions
>> Machine.add("pedestrianSender.ck");      //OSC sender of int values
>>
>> OscRecv receiver;                                //OSC receiver object
>> 6449 => receiver.port;
>> receiver.listen();
>> receiver.event("weather/pedestrian, int") @=> OscEvent pedEvent;
>>
>> -1 => int b3base1;  //int to store a shred ID
>> -1 => int b3base2;  //ditto
>>
>> 25 => int pedCount; //int to store pedCount sent via OSC
>>
>> while (true) {
>>
>>   //if the pedCount is greater than 20 (a value which will be sent via OSC)
>> and b3base1 is equal to -1, i.e. the shred isn't currently running,
>>   //add both shreds to the VM and assign their shred ID to the b3base1 and
>> b3base2
>>
>>   if (pedCount > 20 && b3base1 == -1) {
>>     Machine.add("b3base.ck") => b3base1;
>>     Machine.add("b3base.ck") => b3base2;
>>   }
>>
>>   else {
>>
>>     //if the pedCount is less than 20, remove both shreds from the VM and
>> assign -1 to their value so that if the pedCount goes back above 20 they
>>     //meet the conditional.
>>
>>     if (pedCount < 20 && b3base1 != -1) {
>>       Machine.remove(b3base1);
>>       Machine.remove(b3base2);
>>       -1 => b3base1;
>>       -1 => b3base2;
>>     }
>>   }
>>
>>   while( pedEvent.nextMsg() != 0) {
>>     pedEvent.getInt() => pedCount;
>>     2::second => now;
>>   }
>> }
>>
>> //endcode
>>
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