<td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> <br>
        </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> <br>
      inet_aton（將網(wǎng)絡(luò)地址轉(zhuǎn)成網(wǎng)絡(luò)二進(jìn)制的數(shù)字） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關(guān)函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> inet_addr，inet_ntoa<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 表頭文件 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include&lt;sys/scoket.h&gt;<br>
      #include&lt;netinet/in.h&gt;<br>
      #include&lt;arpa/inet.h&gt;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 定義函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> int inet_aton(const char * cp,struct 
      in_addr *inp);<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數(shù)說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> inet_aton()用來將參數(shù)cp所指的網(wǎng)絡(luò)地址字符串轉(zhuǎn)換成網(wǎng)絡(luò)使用的二進(jìn)制的數(shù)字，然后存于參數(shù)inp所指的in_addr結(jié)構(gòu)中。<br>
      結(jié)構(gòu)in_addr定義如下<br>
      struct in_addr<br>
      {<br>
      unsigned long int s_addr;<br>
      };<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 返回值 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 成功則返回非0值，失敗則返回0。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc273></a></font> </div>
    </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> <br>
        </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> <br>
      inet_ntoa（將網(wǎng)絡(luò)二進(jìn)制的數(shù)字轉(zhuǎn)換成網(wǎng)絡(luò)地址） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關(guān)函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> inet_addr，inet_aton<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 表頭文件 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include&lt;sys/socket.h&gt;<br>
      #include&lt;netinet/in.h&gt;<br>
      #include&lt;arpa/inet.h&gt;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 定義函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> char * inet_ntoa(struct in_addr 
      in);<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數(shù)說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> inet_ntoa()用來將參數(shù)in所指的網(wǎng)絡(luò)二進(jìn)制的數(shù)字轉(zhuǎn)換成網(wǎng)絡(luò)地址，然后將指向此網(wǎng)絡(luò)地址字符串的指針返回。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 返回值 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 成功則返回字符串指針，失敗則返回NULL。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc274></a></font> </div>
    </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> <br>
        </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> <br>
      listen（等待連接） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關(guān)函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> socket，bind，accept，connect<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 表頭文件 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include&lt;sys/socket.h&gt;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 定義函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> int listen(int s,int backlog);<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數(shù)說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> listen()用來等待參數(shù)s 的socket連線。參數(shù)backlog指定同時能處理的最大連接要求，如果連接數(shù)目達(dá)此上限則client端將收到ECONNREFUSED的錯誤。Listen()并未開始接收連線，只是設(shè)置socket為listen模式，真正接收client端連線的是accept()。通常listen()會在socket()，bind()之后調(diào)用，接著才調(diào)用accept()。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 返回值 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 成功則返回0，失敗返回-1，錯誤原因存于errno<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 附加說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> listen()只適用SOCK_STREAM或SOCK_SEQPACKET的socket類型。如果socket為AF_INET則參數(shù)backlog 
      最大值可設(shè)至128。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 錯誤代碼 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> EBADF 參數(shù)sockfd非合法socket處理代碼<br>
      EACCESS 權(quán)限不足<br>
      EOPNOTSUPP 指定的socket并未支援listen模式。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 范例 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include&lt;sys/types.h&gt;<br>
      #include&lt;sys/socket.h&gt;<br>
      #include&lt;netinet/in.h&gt;<br>
      #include&lt;arpa/inet.h&gt;<br>
      #include&lt;unistd.h&gt;<br>
      #define PORT 1234<br>
      #define MAXSOCKFD 10<br>
      main()<br>
      {<br>
      int sockfd,newsockfd,is_connected[MAXSOCKFD],fd;<br>
      struct sockaddr_in addr;<br>
      int addr_len = sizeof(struct sockaddr_in);<br>
      fd_set readfds;<br>
      char buffer[256];<br>
      char msg[ ] =”Welcome to server!”;<br>
      if ((sockfd = socket(AF_INET,SOCK_STREAM,0))&lt;0){<br>
      perror(“socket”);<br>
      exit(1);<br>
      }<br>
      bzero(&addr,sizeof(addr));<br>
      addr.sin_family =AF_INET;<br>
      addr.sin_port = htons(PORT);<br>
      addr.sin_addr.s_addr = htonl(INADDR_ANY);<br>
      if(bind(sockfd,&addr,sizeof(addr))&lt;0){<br>
      perror(“connect”);<br>
      exit(1);<br>
      }<br>
      if(listen(sockfd,3)&lt;0){<br>
      perror(“l(fā)isten”);<br>
      exit(1);<br>
      }<br>
      for(fd=0;fd&lt;MAXSOCKFD;fd++)<br>
      is_connected[fd]=0;<br>
      while(1){<br>
      FD_ZERO(&readfds);<br>
      FD_SET(sockfd,&readfds);<br>
      for(fd=0;fd&lt;MAXSOCKFD;fd++)<br>
      if(is_connected[fd]) FD_SET(fd,&readfds);<br>
      if(!select(MAXSOCKFD,&readfds,NULL,NULL,NULL))continue;<br>
      for(fd=0;fd&lt;MAXSOCKFD;fd++)<br>
      if(FD_ISSET(fd,&readfds)){<br>
      if(sockfd = =fd){<br>
      if((newsockfd = accept (sockfd,&addr,&addr_len))&lt;0)<br>
      perror(“accept”);<br>
      write(newsockfd,msg,sizeof(msg));<br>
      is_connected[newsockfd] =1;<br>
      printf(“cnnect from %s\n”,inet_ntoa(addr.sin_addr));<br>
      }else{<br>
      bzero(buffer,sizeof(buffer));<br>
      if(read(fd,buffer,sizeof(buffer))&lt;=0){<br>
      printf(“connect closed.\n”);<br>
      is_connected[fd]=0;<br>
      close(fd);<br>
      }else<br>
      printf(“%s”,buffer);<br>
      }<br>
      }<br>
      }<br>
      }<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 執(zhí)行 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> $ ./listen<br>
      connect from 127.0.0.1<br>
      hi I am client<br>
      connected closed.<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc275></a></font> </div>
    </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> <br>
        </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> <br>
      ntohl（將32位網(wǎng)絡(luò)字符順序轉(zhuǎn)換成主機(jī)字符順序） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關(guān)函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> htonl，htons，ntohs<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 表頭文件 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include&lt;netinet/in.h&gt;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 定義函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> unsigned long int ntohl(unsigned 
      long int netlong);<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數(shù)說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> ntohl()用來將參數(shù)指定的32位netlong轉(zhuǎn)換成主機(jī)字符順序。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 返回值 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 返回對應(yīng)的主機(jī)字符順序。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 范例 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 參考getservent()。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc276></a></font> </div>
    </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> <br>
        </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> <br>
      ntohs（將16位網(wǎng)絡(luò)字符順序轉(zhuǎn)換成主機(jī)字符順序） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關(guān)函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> htonl，htons，ntohl<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 表頭文件 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include&lt;netinet/in.h&gt;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 定義函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> unsigned short int ntohs(unsigned 
      short int netshort);<br>
      </font> </td>
  </tr>