s.options.verbosity = -1;

s.boot;

a = {
    var trig = Impulse.kr(0);
    Poll.kr(trig, Rand(0, 1));
    FreeSelf.kr(trig <= 0);
    0
}.play;

The Poll output is not printed because verbosity < 0.

I can understand why this was done -- if Poll is considered to be "informational" and verbosity = -1 means to suppress informational messages, then of course you wouldn't see anything.

I disagree that Poll is informational. This is output that the user explicitly requested by writing the unit into a SynthDef. That differentiates it from messages posted by scsynth, without the user's intent.

Possible solutions:

1. Always print Poll output, no matter the verbosity level.
2. Or, if you may want to suppress it sometimes, change the verbosity to be a mask system. Verbosity = -1 (0xFFFFFFFF) could mean print everything.

-2 (0xFFFFFFFE), suppress informational messages
-3 (0xFFFFFFFD), suppress error messages
-5 (0xFFFFFFFB), suppress Poll and other explicit messages

Then these could be bitAnd'ed to control the behavior individually, so, for example, you could keep error messages but suppress informational+Poll by -6.

Use case: NRT analysis. It would be useful to get Poll printouts without the whole slew of "next OSC packet" informational messages. Currently impossible.