程嶏清单 17-4.txt

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程序清单17-4：client.pl
#!/usr/bin/perl
 #
 # define constants for talking to server
 #
 $PACKIT = 'S n C4 x8';
 $AF_INET = 2;
 $SOCK_STR = 1;     # STREAMS
 $DEF_PROTO = 0;    #default protocol of IP
 $port = 6668 unless $port;
    
 #
 # Get the name of the server
 #
 ($name, $aliases, $addrtype, $len, @addrs) = gethostbyname("www.ikra.com"); 
 ($a,$b,$c,$d) = unpack('C4',$addrs[0]);
 print "Server Name=$name, Server Address= $a.$b.$c.$d\n"; 
 $that = pack($PACKIT,$AF_INET,$port,$addrs[0]);
  
 #
 # Confine yourself to the local host machine address of 127.0.0.1 
 #
 $this = pack($PACKIT,$AF_INET,$port,127,0,0,1);
    
 #
 # Disable buffering on this socket.
 #
 select(CLIENT_SOCKET);
 $| = 1;
 select(stdout);
  
  
 socket(CLIENT_SOCKET,$AF_INET,$SOCK_STR,$DEF_PROTO) 
or  die "$0: Cannot open socket\n";
 print "Created socket\n";

 #
 # Attempt to connect to server.
 #
 do
 {
  sleep(1);
   $result = connect(CLIENT_SOCKET,$that);
   i f (result != 1) {
       print "Sleeping\n"; 
      }

 } while ($result != 1);

 sleep(5);
 print "After connection\n";
  
 #
 # send data to server
 #
 # write(CLIENT_SOCKET,"hello",5);

 read(CLIENT_SOCKET,$buf,100);

 print "[" . $buf . "]\n";
 close(CLIENT_SOCKET);
# end of client program