in reply to Perl Alarm Not Working

With Deferred (or Safe) Signals enabled--the default since 5.8.something--there are (many) somethings that cannot be interrupted by SIGALRM.

Reading your later description of do_program(), it seems like that it is doing many, maybe even most, of those somethings.

You may find the use of Perl::Unsafe::Signals worth testing.

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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Re^2: Perl Alarm Not Working
by ikegami (Patriarch) on Dec 19, 2010 at 21:21 UTC
    The db code won't be interruptible* (a good thing), but the LWP stuff will be. No idea what "abstract the site page information" means, much less how it's implemented, so I don't know about that.

    * — That means the signal handler will be called when the db code returns if the signal was sent when the db code was executing.

[reply]
      the LWP stuff will be [interuptable]

      You sure?

      When I run the following two one liners, 'here' is printed after 30 seconds--when the server times out--not after 10 as it would be if the alarm had interupted the socket read. 

      C:\test>start /b perl -MIO::Socket 
-E"$s=IO::Socket::INET->new(Listen=>1,LocalPort=>12345);$c=$s->accept;
+sleep 30"

C:\test>perl -MIO::Socket 
-E"$s=IO::Socket::INET->new('localhost:12345');eval{alarm 10;<$s>};pri
+nt'here'"
here

      [download]
      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]
        C:\test>start /b perl -MIO::Socket 
-E"$s=IO::Socket::INET->new(Listen=>1,LocalPort=>12345);$c=$s->accept;
+sleep 30"

C:\test>perl -MIO::Socket 
-E"$s=IO::Socket::INET->new('localhost:12345');eval{alarm 10;<$s>};pri
+nt'here'"
here

        [download]

        Windows has no signals. Not even SIGALRM. Perl emulates them, and the emulation is far from perfection. (It's actually pretty good, given that ugly Windows API.)

        Alexander

        --
        Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)
[reply]
[d/l]

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