Re: Waiting for Alarm

alarm does wake the program in sleep, at least on my perl, v5.10.0 built for MSWin32-x86-multi-thread.

Here is the code

use strict;

sub Call_with_Timeout{
   my ($TIMEOUT, $CODEREF) = @_;

   eval {
      local $SIG{ALRM} = sub { die "alarm time out" };
      alarm $TIMEOUT;
      $CODEREF->(); # Whatever needs to be done
      alarm 0;
      1;  # return value from eval on normalcy
  } or return -1; # Timeout happened
  return 1; # OK
}

 my $t=Call_with_Timeout(3, sub{ sleep 3, print "$_.\n" for 1..2});
   print "Timed out=$t;\n";
[download]

prints
Timed out=-1;
Which means that the alarm woke it up.

"As you get older three things happen. The first is your memory goes, and I can't remember the other two... " - Sir Norman Wisdom

Comment on Re: Waiting for Alarm Download Code

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Re^2: Waiting for Alarm by n8ur (Acolyte) on Feb 16, 2008 at 18:21 UTC
When I tried using sleep in the loop, it bombed out after the first alarm -- I got one print from the handler, and then the program exited. However, I just tried again with this: #!/usr/bin/perl use Time::HiRes qw ( setitimer ITIMER_REAL time ); my $count; $SIG{ALRM} = sub { print time, "\n" }; setitimer(ITIMER_REAL, 1, 1); while (1) { sleep 1; } and it worked fine. If this is reliable, it does the job for me. But I wonder why the first time it only worked for the first iteration... Thanks!	[reply]
Re^3: Waiting for Alarm by n8ur (Acolyte) on Feb 16, 2008 at 18:23 UTC
Ignore the "my $count" -- that's left over from an earlier experiment. Apart from the while loop, this is based on an example in the Time::HiRes documentation.	[reply]