If your primary goal is to avoid drift, then this routine will do the trick (within the limitations of the system clock):
  
$|= 1;
my $i;
my $start_time = time;
my $period = 60;
while (1) {
    print time, "\n";
    my $next_sleep = ($start_time + $period * ++$i) - time;
    sleep $next_sleep;
}

[download]
This guarantees that future samples won't compound the timming imprecisions of prior samples. 
   MeowChow                                   
               s aamecha.s a..a\u$&owag.print

In reply to (MeowChow) Re: Reasonably accurate timing by MeowChow
in thread Reasonably accurate timing by traveler

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