隨手記錄

unless ($peer = accept NS, S){

    die "Can't accept a connection: $!\n";

}

while(1) { accept( NEW_SOCKET, SOCKT ); ....... }

#!/usr/bin/perl -T
use strict;
use warnings;
BEGIN { $ENV{PATH} = "/usr/bin:/bin" }
use Socket;
use Carp;
my $EOL = "\015\012";

sub logmsg { print "$0 $$: @_ at ", scalar localtime(), "\n" }

my $port  = shift || 2345;
die "invalid port" unless $port =~ /^ \d+ $/x;

my $proto = getprotobyname("tcp");

socket(my $server, PF_INET, SOCK_STREAM, $proto) || die "socket: $!";
setsockopt($server, SOL_SOCKET, SO_REUSEADDR, pack("l", 1))
                                              || die "setsockopt: $!";
bind($server, sockaddr_in($port, INADDR_ANY)) || die "bind: $!";
listen($server, SOMAXCONN)                    || die "listen: $!";

logmsg "server started on port $port";

for (my $paddr; $paddr = accept(my $client, $server); close $client) {
    my($port, $iaddr) = sockaddr_in($paddr);
    my $name = gethostbyaddr($iaddr, AF_INET);

    logmsg "connection from $name [",
            inet_ntoa($iaddr), "]
            at port $port";

    print $client "Hello there, $name, it's now ",
                    scalar localtime(), $EOL;
}