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Poll : UGen : AbstractFunction : Object

Print the current output value of a UGen
Source: Poll.sc


Print the current output value of a UGen, useful for debugging SynthDefs.

WARNING: Printing values from the Server in intensive for the CPU. Poll should be used for debugging purposes.

Class Methods

Poll.ar(trig, in, label, trigid: -1)

Poll.kr(trig, in, label, trigid: -1)



a non-positive to positive transition telling Poll to return a value


the signal you want to poll


a string or symbol to be printed with the polled value


if greater then 0, a '/tr' message is sent back to the client (similar to SendTrig)


its in signal (and is therefore transparent).

Inherited class methods

Instance Methods

Inherited instance methods



{ Poll.kr(Impulse.kr(10), Line.kr(0, 1, 1), \test) }.play(s);

// multichannel expansion:

{ Poll.kr(Impulse.kr([10, 5]), Line.kr(0, [1, 5], [1, 2]), [\test, \test2]) }.play(s);

// using the poll message:

{ SinOsc.ar(375, 0, 1).poll(Impulse.ar(20), \test2) }.play(s);

// if no arguments are given, the poll is done every 0.1 sec.
{  Line.kr(0, 1, 1).poll }.play(s);

// send a '/tr' message back to the client. This can be useful if the server runs on another
// computer than the client, i.e. the post messages by the server cannot be read locally.

o = OSCFunc({arg msg; msg.postln;}, '/tr', s.addr);

{Poll.ar(Impulse.ar(5), Line.ar(0, 1, 1), \test2, 1234)}.play(s);
{SinOsc.ar(220, 0, 1).poll(Impulse.ar(15), "test", 1234)}.play(s);


// This example will kill the server (by outputting NaN).
// Poll.ar will help us spot why it's happening.
// Warning: You may need to reboot your server after running this.
var cutoff, son;
cutoff = LFPar.kr(0.2, 0, 500, 500);
son = LPF.ar(WhiteNoise.ar, cutoff);

// Using Poll to debug by spitting out a value if the output hits NaN
Poll.ar(if((son<=0)||(son>=0), 0, 1), cutoff, "Cutoff value which causes NaN:");



// This example polls when someone hits the trigger
x = {|t_poll=0|
var minfreq, maxfreq, son;
minfreq = LFNoise2.ar(0.25, 100, 110);
maxfreq = LFNoise2.ar(0.25, 200, 220);

son = Gendy1.ar(minfreq: minfreq, maxfreq: maxfreq, mul: 0.1);

Poll.kr(t_poll, [minfreq, maxfreq], ["minfreq", "maxfreq"]);



x.set(\t_poll, 1); // Hit this whenever you want to know what the parameters are