Re: Why do my threads sometimes die silenty?

Seems to me a thread can exit in one of three ways.

By throwing an exception.

$ perl -Mthreads -e'my $t = async { die "Foo" }; $t->join; say "done"'
Thread 1 terminated abnormally: Foo at -e line 1.
done
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This isn't silent.

By returning.

$ perl -Mthreads -E'my $t = async { "code" }; $t->join; say "done"'
done
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You can detect this as follows:

$ perl -Mthreads -E'sub t { "code" } my $t = async { t(); warn("return
+ed"); }; $t->join; say "done"'
returned at -e line 1.
done
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By calling threads->exit

$ perl -Mthreads -E'sub t { "code" } my $t = async { threads->exit(); 
+}; $t->join; say "done"'
done
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You can detect this as follows:

$ perl -Mthreads -E'my $o = \&threads::exit; *threads::exit = sub { wa
+rn "exit"; $o->(@_) }; my $t = async { threads->exit(); }; $t->join; 
+say "done"'
exit at -e line 1.
done
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Another possibility is that your thread isn't responding because it's blocked, not because it exited. What makes you think it died?

Comment on Re: Why do my threads sometimes die silenty? Select or Download Code

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Re^2: Why do my threads sometimes die silenty? by BrowserUk (Patriarch) on Sep 21, 2011 at 20:18 UTC
There is at least one more way: `C:\test>perl -Mthreads -E"my $t = async { die "Foo" }->detach; say 'do +ne'" done` [download] And I'm pretty sure I could come up with a few more. 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] [d/l]
Re^3: Why do my threads sometimes die silenty? by ikegami (Patriarch) on Sep 21, 2011 at 21:09 UTC
I'm pretty sure the OP meant the thread exited before the process terminated. Note that the above is not silent if the `die` has a chance to execute. (About 50% of the time on this machine.)	[reply] [d/l]
Re^4: Why do my threads sometimes die silenty? by BrowserUk (Patriarch) on Sep 21, 2011 at 21:18 UTC
Note that the above is not silent if the die has a chance to execute. Yes, but it turns out that is exactly what he was doing. At least in his experiments: There are other ways. For example, there were a bunch of versions of perl (most of the 5.8.x series from memory) that (on Windows) silently exited if they ran "Out of memory!" never producing that error message. I had that happen a lot. Also, hard to demo since dave-the-m changed the regex engine from recursive to iterative, but previously running a pathological regex in a thread could run it out of C-stack and it would silently disappear. There aren't many things left in perl that consume stack any more, but I wouldn't mind betting that if we could find one, that the thread would still terminate silently. 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]
Re^5: Why do my threads sometimes die silenty? by ikegami (Patriarch) on Sep 21, 2011 at 22:09 UTC
Re^6: Why do my threads sometimes die silenty? by BrowserUk (Patriarch) on Sep 21, 2011 at 22:17 UTC