in reply to Re^4: Why do my threads sometimes die silenty?
in thread Why do my threads sometimes die silenty?

Here is an example that more closely approximate my app's situation: 
use strict;

use threads;
use threads::shared;
use Thread::Pool;

my $signal = undef;
share($signal);
my $fct = 
        sub {
            require Blah; Blah->import(); 
            $signal = 1;
        };
print "Starting the Thread::Pool\n";
my $pool = Thread::Pool->new(
                {do => $fct});
print "Thread::Pool started\n";

print "Sending a job to the Thread::Pool\n";
$pool->job();
print "Job sent to the Thread::Pool\n";

print "Waiting for the slave thread to set the shared signal\n";
while (!$signal) {
    print "Sleeping and waiting for signal from slave thread\n";
    sleep(1);
}
print "Got shared signal from slave thread\n";

$pool->shutdown();

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When I run it, I get: 
Starting the Thread::Pool

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And it gets stuck there, without outputting any error message. Obviously here, the slave gets a slice of CPU, since I sleep for 1 second between polls of the shared signal.

Note that if I coment out the faulty require line, I do get the proper behaviour, i.e. the script prints: 
Starting the Thread::Pool
Thread::Pool started
Sending a job to the Thread::Pool
Job sent to the Thread::Pool
Waiting for the slave thread to set the shared signal
Sleeping and waiting for signal from slave thread
Got shared signal from slave thread

[download]

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Re^6: Why do my threads sometimes die silenty?
by BrowserUk (Patriarch) on Sep 21, 2011 at 21:33 UTC

    What happens (*) if you change this:

    my $signal = undef;
share($signal);

    [download]

    To: my $signal :shared; ?

    I can't test it as I don't have Thread::Pool. It isn't available as a PPM for my version of Perl and I cannot be bothered to try and track down the numerous crappy, bloated dependencies it has to install it manually, given that I would never use it.

    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
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[d/l]
[select]
      Changed the $signal declaration to my $signal :shared; as you suggested, and I get the same behaviour as before. The thread never returns (because of the faulty "use Blah"), but I never see the error message. Alain
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[d/l]

        Sorry, but I cannot even begin to see how to debug Thread::Pool. You're best bet would be to raise the problem with the maintainer.

        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]

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