What else can i do 'sleep' when the sleep() can't work well with alarm?

Question

There are many documents say "you should avoid using sleep with alarm, since many systems use alarm for the sleep implementation". And actually, I'm suffering with this problem. So does anyone can help me that what else i can do 'sleep' when the sleep() can't work well with alarm? I have already tried 'usleep' of the Time::HiRes module, and select() function. But they didn't work either.

Answer 1

Seeing as you're being interrupted by alarms, and so can't reliably use sleep() or select(), I suggest using Time::HiRes::gettimeofday in combination with select().

Here's some code that I've not tested. It should resist being interrupted by signals, and will sleep for the desired number of seconds plus up to 0.1 seconds. If you're willing to burn more CPU cycles doing nothing productive, you can make the resolution much better:

...
alarm_resistant_sleep(5); # sleep for 5 seconds, no matter what
...

use Time::HiRes;

sub alarm_resistant_sleep {
  my $end = Time::HiRes::time() + shift();
  for (;;) {
    my $delta = $end - Time::HiRes::time();
    last if $delta <= 0;
    select(undef, undef, undef, $delta);
  }
}

Answer 2

You can try AnyEvent:

use AnyEvent;

my $cv = AnyEvent->condvar;
my $wait_one_and_a_half_seconds = AnyEvent->timer(
    after => 1.5,
    cb => sub { $cv->send }
);     
# now wait till our time has come
$cv->recv;