Perl listen 函数

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  描述

  listen 此函数将网络套接字SOCKET配置为侦听传入的网络连接。将传入连接队列长度设置为EXPR。您可能需要考虑使用IO :: Socket模块，该模块提供了一种创建和侦听网络套接字的简便方法。
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  句法

  以下是此函数的简单语法-

  
  listen SOCKET, EXPR
  

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  返回值

  如果失败，此函数返回0，如果成功，则返回1。
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  示例

  以下是显示其基本用法的示例代码-

   
  use strict;
  use Socket;
  
  # use port 7890 as default
  my $port = shift || 7890;
  my $proto = getprotobyname('tcp');
  
  # create a socket, make it reusable
  socket(SOCKET, PF_INET, SOCK_STREAM, $proto) 
     or die "Can't open socket $!\n";
  setsockopt(SOCKET, SOL_SOCKET, SO_REUSEADDR, 1) 
     or die "Can't set socket option to SO_REUSEADDR $!\n";
  
  # bind to a port, then listen
  bind( SOCKET, pack( 'Sn4x8', AF_INET, $port, "\0\0\0\0" ))
         or die "Can't bind to port $port! \n";
  listen(SOCKET, 5) or die "listen: $!";
  print "SERVER started on port $port\n";
  
  # accepting a connection
  my $client_addr;
  while ($client_addr = accept(NET_SOCKET, SOCKET)) {
     # send them a message, close connection
     print NEW_SOCKET "Smile from the server";
     close NEW_SOCKET;
  }