Re: Is this a bug of perl threads?

I can reproduce the problem with your client/server combo. Running the server part under strace indicated the process had been "killed by SIGPIPE":

...
[pid 27966] write(4, "58\n", 3)         = -1 EPIPE (Broken pipe)
[pid 27966] --- SIGPIPE (Broken pipe) @ 0 (0) ---
Process 27966 detached
[pid 27967] <... accept resumed> 0x4219cef0, [4096]) = ? ERESTARTSYS (
+To be restarted)
[pid 27967] +++ killed by SIGPIPE +++
Process 27967 detached
[pid 27968] <... accept resumed> 0x4299def0, [4096]) = ? ERESTARTSYS (
+To be restarted)
[pid 27968] +++ killed by SIGPIPE +++
Process 27968 detached
<... futex resumed> )                   = ? ERESTARTSYS (To be restart
+ed)
+++ killed by SIGPIPE +++
[download]

Adding $SIG{PIPE} = 'IGNORE' to the server code solved the issue for me. You probably also want to check if the print $client "$second\n" failed, in which case you should close the connection properly (otherwise, the respective threads will remain busy for 60 seconds printing to nowhere...):

    ...
        for ($second=60; $second>0; --$second) {
                sleep 1;
                last unless print $client "$second\n";
        }
        close $client;
    ...
[download]

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Re^2: Is this a bug of perl threads? by Ray.Zachary (Acolyte) on Mar 12, 2010 at 04:05 UTC
WOOOOOW, That's awesome! You are right! Thank you almut, and thanks everybody, that problem was solved with handling $SIG{PIPE}. Seems I need going to read some papers about signals.	[reply]
Re^3: Is this a bug of perl threads? by ikegami (Patriarch) on Mar 12, 2010 at 04:38 UTC
That particular signal occurs when you attempt to write to a pipe or socket that's been disconnected. The default action is to kill the process. You can safely ignore the signal. In exchange, you should check if `print` succeeds, and exit the loop if not. `sub server { local $SIG{PIPE} = 'IGNORE'; while (my $client = $server->accept()) { for my $sec (1..60) { sleep 1; print $client "$sec\n" or last; } } }` [download]	[reply] [d/l] [select]