Re: Catching signals under Linux

On a more elementary level, why does this code:

use strict;
use warnings;
use 5.010;
use threads;

sub thr_func
{
    say 'in thread';
    $SIG{'HUP'} = sub { say "signal caught" };
}

my $thr = threads->create('thr_func');
$thr->kill('HUP')->join();
[download]

produce this output:

Signal SIGHUP received, but no signal handler set.
[download]

The threads docs seem pretty clear that you can signal a thread.

Comment on Re: Catching signals under Linux Select or Download Code

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Re^2: Catching signals under Linux by JavaFan (Canon) on Jan 29, 2010 at 10:57 UTC
Because you're likely to send the signal before the other thread was able to set the handler. Note that your output doesn't include 'in thread', which is printed before you set SIGHUP.	[reply]
Re^3: Catching signals under Linux by locked_user sundialsvc4 (Abbot) on Jan 29, 2010 at 18:17 UTC
I have not looked closely at your code, but I would observe that the scenario just described is extremely common, and therefore extremely likely.
Re^3: Catching signals under Linux by 7stud (Deacon) on Jan 29, 2010 at 11:29 UTC
Yup: `use strict; use warnings; use 5.010; use threads; sub thr_func { say 'in thread'; $SIG{'HUP'} = sub { say "signal caught" }; say 'doing some task...'; sleep 5; } my $thr = threads->create('thr_func'); sleep 2; $thr->kill('HUP')->join(); --output:-- in thread doing some task... signal caught` [download] Thanks.	[reply] [d/l]