Non-Blocking I/O in Perl - an Example

  • Presented by Barry Brevik
  • Presentation at: http://manicreader.com/perl/socktalk.html
  • Code at: http://manicreader.com/perl/socketprint.txt

Non-Blocking I/O in Perl - an Example

        
    
          
  • use IO::Handle;
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  • use IO::Socket;        # Imports IO::Handle.
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  • use IO::Socket::INET;  # Imports IO::Socket.
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  • Book: Network Programming with Perl by Lincoln Stein,
    Addison Wesley ISBN 0-201-61571-1.
          
  • Book: Perl Cookbook by Christiansen & Torkington,
    O'Reilly ISBN 1-56592-243-3.

Non-Blocking I/O in Perl - an Example

        
    
          
  • use Socket;      # Native Perl.
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  • my $printProtocol = (getprotobyname('tcp'))[2];
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  • my $binaryIP = pack('C4', split(/\./, '10.18.0.30'));  or
    my $binaryIP = inet_aton('10.18.0.30')
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  • socket(PRINTER, AF_INET, SOCK_STREAM, $printProtocol);
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  • connect(PRINTER, pack('Sna4x8', AF_INET, 9100, $binaryIP));
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Non-Blocking I/O in Perl - an Example

        
    
          
  • Four argument select statement ready file descriptors.
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  • vec($readyOut, fileno(PRINTER), 1) = 1;
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  • select $readyIn, $readyOut, $exceptIn, <timeout>;
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  • $readyIn = is your file descriptor ready to send data?
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  • $readyOut = is your file descriptor ready to receive data?
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  • $readyExcept = is your file descriptor trying to send you
    an exception such as an out of band or urgent msg?
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