Re^4: Print inside SIGNALS

This code does not work...

alarm 2;
$SIG{ALRM} = \&Finish;
my $a=<>;

sub Finish { print "Timeout reached"; }
[download]

This code does not work either...

alarm 2;
$SIG{ALRM} = \&Finish;
while (1==1){};

sub Finish { print "Timeout reached"; }
[download]

So i guess many calls are not interrumptibles... am i right>?

Comment on Re^4: Print inside SIGNALS Select or Download Code

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Re^5: Print inside SIGNALS by haukex (Archbishop) on Jul 16, 2018 at 20:20 UTC
So i guess many calls are not interrumptibles... am i right? I don't think that's the problem here - see my reply to your nearly identical post here.	[reply]
Re^5: Print inside SIGNALS by ikegami (Patriarch) on Jul 17, 2018 at 11:22 UTC
First snippet: `<>` can't be interrupted because there's no way to check `<>` for errors. However, the signal handler does get called once it returns. Second snippet: There's nothing to interrupt here, so the signal handler gets called immediately. However, since the program has no way of terminating the program cleanly, the message will never leave STDOUT's buffer to the underlying file system handle.	[reply] [d/l] [select]
Re^6: Print inside SIGNALS by haukex (Archbishop) on Jul 17, 2018 at 11:50 UTC
First snippet: `<>` can't be interrupted because there's no way to check `<>` for errors. However, the signal handler does get called once it returns. At least on my machine (Linux), it seems to be the same buffering issue... `$ perl -wMstrict -e 'alarm 2; $SIG{ALRM}=sub{ print "Timeout reached" };<>' ^C $ perl -wMstrict -e 'alarm 2; $SIG{ALRM}=sub{ print "Timeout reached\n" };<>' Timeout reached ^C $ perl -wMstrict -e 'alarm 2; $SIG{ALRM}=sub{ print STDERR "Timeout reached" };<>' Timeout reached^C` [download]	[reply] [d/l] [select]
Re^7: Print inside SIGNALS by ikegami (Patriarch) on Jul 17, 2018 at 16:18 UTC
No, "it didn't work" for you because you killed the program before the signal handler was called.	[reply]
Re^8: Print inside SIGNALS by haukex (Archbishop) on Jul 17, 2018 at 18:14 UTC
Re^9: Print inside SIGNALS by ikegami (Patriarch) on Jul 18, 2018 at 11:20 UTC
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