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Re: Re: Can I timeout an accept call?

by Declarent (Sexton)
on Jun 10, 2002 at 16:09 UTC ( [id://173208]=note: print w/replies, xml ) Need Help??

in reply to Re: Can I timeout an accept call?
in thread Can I timeout an accept call?

Many thanks to you, Monks!

After much fiddling with the ideas here, I decided on another way of doing it. Here's what I decided:

I'm using IO::Socket::INET, so my ports are defaulted to non-blocking. Sadly, that means that as soon as I get any connection from the client, I can get an undef on that port during a pause or after input during the next cycle. So that was out.

I then set the port to block, and set the Timeout value, but it wouldn't time out for me at accept. Dunno why that is, I'm on *nix, so it should work. *shrug*

So, I set the thing to block, and after the accept I added:

$test=$data_port->peerhost(); if (not defined $test){close_data_port;}
That way, during any client pause, the connection is still open, so peerhost returns it's IP address. When the connection drops, that value goes undef and I call my exit sub.

Now, my population explosion is under control. Many Thanks!


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Re: Re: Re: Can I timeout an accept call?
by Fastolfe (Vicar) on Jun 10, 2002 at 22:48 UTC
    Unfortunately, non-blocking IO isn't as simple as blocking IO. I'm not sure why you say that your sockets are "defaulted to non-blocking" simply by virtue of using IO::Socket::INET. To my knowledge, sockets created from this module are not automatically placed in a non-blocking state unless you explicitly ask for them that way.

    To get around the fact that many of your non-blocking socket calls will immediately return (frequently with 'undef'), you should use IO::Select to detect when a socket has something for you, or when a socket is available to accept data. It's generally safe then to read from or write to a socket such that you won't block, and won't get 'undef' (unless it really means it).

    Unfortunately this logic tends to add a lot of additional complexity to your code. Fortunately, much of this has already been encapsulated in some Perl modules, POE being the most noteworthy.

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