But I need better resolution than one second.

Oh, sorry, didn't listen carefully. Then use Time::HiRes, which is a core module on newer perls: 

perl -we 'use Time::HiRes "time"; print time, "\n";'

[download]
or the gettimeoftheday function from the same module, or (on linux) 
perl -we 'defined(syscall 78, ($d = pack "x100"), 0) or die "panic: ge
+ttimeofday failed $!"; ($s, $u) = unpack "l!l!", $d; printf "%d.%06d\
+n", $s, $u;'

[download]
but 156 instead of 78 on solaris, and 116 (untested) instead of 78 on freebsd, (Update:) 96 instead of 78 on linux-x86_64.

Update:

Before every tick, get the current time, and wait whatever time is left till the next tick.
That's essentially what I'm already doing.
My point is that you have to ask for the time before every sleep. I don't see your code, so you might already be doing that. Of course, if you spawn an external process for querying the time, then that's slow, so don't do that.

In reply to Re^3: making something happen in real time by ambrus
in thread making something happen in real time by bcrowell2

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