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Re^3: Signal to a sleeping Perl program

by QM (Parson)
on Jan 20, 2020 at 10:59 UTC ( #11111628=note: print w/replies, xml ) Need Help??


in reply to Re^2: Signal to a sleeping Perl program
in thread Signal to a sleeping Perl program

Any signal, or at least any non-ignored signal interrupts sleep.

Many forget this, and expect that a literal sleep 60 may not actually take 60s, but could be anything less than that. In one-off scripts I've seen code like this (untested):

sub my_sleep { my $sleep_time = (shift or 1); # total time to sleep my $sleep_interval = (shift or 10); # wake up at least this often my $start = time; $stop_time = $start + $sleep_time; while (time < $stop_time) { sleep $sleep_time; # handle wake up tasks } my $elapsed = time - $start; return $elapsed; # total time actually slept (plus shipping and ha +ndling) }

You may want additional conditions, and use this as a timeout mechanism. There's probably a nice module for that, or roll your own.

But the point is sleep comes with an unspoken if (...), if something else doesn't wake me up.

-QM
--
Quantum Mechanics: The dreams stuff is made of

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