http://www.perlmonks.org?node_id=1000702

tenny1204 has asked for the wisdom of the Perl Monks concerning the following question:

I wrote some socket-communication programs and now I want to rewrite them using the built-in functions iso the IO::Socket library.But i can't figure out how to set a timeout like you can do in the constructor when using IO::Socket.What i tried was adding these 2 lines of code for setting a 1 second timeout.

setsockopt(SOCKET,SOL_SOCKET,SO_SNDTIMEO,pack("LL",1,0));
setsockopt(SOCKET,SOL_SOCKET,SO_RCVTIMEO,pack("LL",1,0));

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They don't work and i can't find out what does. Maybe someone can help me, Thank you in advance

Replies are listed 'Best First'.
Re: built-in socket functions
by Anonymous Monk on Oct 25, 2012 at 02:33 UTC

    What kind of socket do you have?

    Doesn't SO_SNDTIMEO require blocking sockets?

    Why aren't you error checking? 

    setsockopt ... or die Fudge("SO_SNDTIMEO");
setsockopt ... or die Fudge("SO_RCVTIMEO");
sub Fudge {
    use Errno();
    join qq/\n/,
      "Error @_",
      map { "  $_" } int( $! ) . q/ / . $!,
      int( $^E ) . q/ / . $^E,
      grep( { $!{$_} } keys %! ),
      q/ /;
}

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[d/l]

      I tried errorchecking but no error, doesn't even seem to matter what i write after pack().I have something like: 

      $port=80;
$proto=getprotobyname('tcp');
socket(SOCKET,AF_INET,SOCK_STREAM,$proto) or die "no socket";
setsockopt(SOCKET,SOL_SOCKET,SO_RCVTIMEO,pack("LL",1,0));
$iadr = inet_aton("127.0.0.1");
$padr=sockaddr_in($port,$iadr);
if(connect(SOCKET,$padr)){
print "connection ok";}
else{print "$!\n";}

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      It should correspond to something like:

      $conn = IO::Socket::INET->new(
    PeerAddr=>"127.0.0.1",
    PeerPort=>80,
    Proto=>'tcp',
    Timeout=> 1, 
        Blocking=>1    );

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      So: a blocking socket with a 1 second timeout because now the standardtimeout is something like 10 seconds,making my applications run slower iso faster which was the general idea.

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[d/l]
[select]

        See Re: how to set socket recv timeout in architecture independent manner?

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        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.

        RIP Neil Armstrong
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Re: built-in socket functions
by zentara (Archbishop) on Oct 25, 2012 at 10:42 UTC
    If you havn't seen it, cookbook example

    They use a syntax like 

    use Socket;
require "sys/socket.ph";    # for &TCP_NODELAY

setsockopt(SERVER, SOL_SOCKET, &TCP_NODELAY, 1)
    or die "Couldn't disable Nagle's algorithm: $!\n";

Re-enable it with:

setsockopt(SERVER, SOL_SOCKET, &TCP_NODELAY, 0)
    or die "Couldn't enable Nagle's algorithm: $!\n";

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    I'm not really a human, but I play one on earth.
    Old Perl Programmer Haiku ................... flash japh
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[d/l]
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