Using socket descriptor with IO::Select

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

Hi! I have looked in the FAQs for an answer, but I can't find anything similar.

I am in the process of writing a Perl module to interface an OEM C library to Perl.
A C function returns a socket descriptor, from socket().
I would like to use IO::Select to determine when the socket is ready to read.
The code I have works under UNIX Perl, but not WIN-NT Perl. (Perl 5.00503)
I think that I need to somehow insert the socket descriptor into a Perl IO::Socket object, but I can't figure out how to do that.

What do I need to do to get IO::Select to accept a socket descriptor?

Thanks.

-- BrianCM

 
#####################################################
# ConConnect is an OEM function to make TCP connection 
# to a server.
$sd = ConConnect( $ENV{'CCHOST'}, $ENV{'CCPORT'} );
croak( "ConConnect failed" ) if $sd == &ConLib::INVALID_SOCKET;
 
#
# ...... code deleted
# At this point $sd is a valid socket
 
# Add descriptors for select call
$allfds->add( \*STDIN );
$allfds->add( $sd ); # I presume the problem is here.
                     # Works for UNIX, not Win-NT
 
while( 1 ) {
 my @fds = $allfds->can_read( undef ); # hangs here on NT
 foreach my $stream (@fds) {
  if( $stream == \*STDIN ) {
   last if processStdin() < 0;    # process STDIN stream
  }
  if( $stream == $sd ) {
   last if processInput( $sd ) < 0;    # procComment on Using socket descriptor with IO::Select

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RE: Using socket descriptor with IO::Select by ender (Novice) on Mar 22, 2000 at 23:50 UTC
Ok, the following is taken from a simple perl irc server that I was using as a basis for writing something else. Is this what you were talking about? This is very simple, and just prints everything that it gets out. It's simpler than it looks, I promise. Just look it over. #!/usr/bin/perl use strict; use IO::Socket; use IO::Select; use POSIX; my $server; my $select; my %clients; $SIG{INT} = sub { foreach(values(%clients)) { close; } close $server; exit; }; sub start_listening { $server = IO::Socket::INET->new(Proto=>"tcp", LocalPort=>"8900", Listen=>1) or die "Can't open socket\n"; $select = IO::Select->new($server); } sub main_loop { while(1) { foreach my $client ($select->can_read(1)) { if($client == $server) { #connection waiting to be handled... $client = $server->accept(); $select->add($client); &setnonblocking($client); $clients{$client} = $client; } elsif(defined($clients{$client})) { my $pending; my $data; $pending = $client->recv($data,POSIX::BUFSIZ,0); if($pending) { print $data; } } } } } sub setnonblocking { my $sock = shift; # Get the current state of the socket.. my $flags = fcntl($sock, F_GETFL, 0) or die "Can't get the flags on socket: $!\n"; # ..and then add O_NONBLOCK (nonblocking-ness) on to it. fcntl($sock, F_SETFL, $flags \| O_NONBLOCK) or die "Can't set socket non-blocking: $!\n"; } start_listening(); main_loop();	[reply]

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RE: Using socket descriptor with IO::Select
by ender (Novice) on Mar 22, 2000 at 23:50 UTC


#!/usr/bin/perl

use strict;

use IO::Socket;
use IO::Select;
use POSIX;

my $server;
my $select;
my %clients;

$SIG{INT} = sub { foreach(values(%clients)) { close; } close $server; exit; };

sub start_listening {
  $server = IO::Socket::INET->new(Proto=>"tcp", LocalPort=>"8900", Listen=>1) or
 die "Can't open socket\n";
  $select = IO::Select->new($server);
}

sub main_loop {
  while(1) {
    foreach my $client ($select->can_read(1)) {
      if($client == $server) { #connection waiting to be handled...
        $client = $server->accept();
        $select->add($client);
        &setnonblocking($client);
        $clients{$client} = $client;
      } elsif(defined($clients{$client})) {
        my $pending;
        my $data;
        
        $pending = $client->recv($data,POSIX::BUFSIZ,0);
        
        if($pending) {
          print $data;
        }
      }
    }
  }
}

sub setnonblocking {
  my $sock = shift;
  # Get the current state of the socket..
  my $flags = fcntl($sock, F_GETFL, 0) or
    die "Can't get the flags on socket: $!\n";
  # ..and then add O_NONBLOCK (nonblocking-ness) on to it.
  fcntl($sock, F_SETFL, $flags | O_NONBLOCK) or
    die "Can't set socket non-blocking: $!\n";
}   

start_listening();
main_loop();

[reply]