Winsock学习1:用winsock实现socket通讯的server端。

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本文介绍了学习winsock api时，参照书上例子实现server端的源码。在VC++6.0下编译时，出现winsock api函数名不能解析的错误，如error LNK2001等。通过在工程中project-->setting-->Link-->Object/Library modules添加ws2_32.lib解决了该问题。

学习winsock api,参照书上写的server端的例子。

源码如下：

/*
*File:Server.cpp
*
*/

#include <winsock2.h>
#include <stdio.h>
#include <stdlib.h>

#define DEFAULT_PORT 5150
#define DEFAULT_BUFFER 4096
int iPort = DEFAULT_PORT;

BOOL bInterface = TRUE ;
BOOL bRecvOnly = FALSE;
char szAddress[128];
//Function:usage
//Description:
// Print usage information and exit
void usage()
{
printf("usage:server [-p:x] [-i:ip] [-o]/n/n");
printf("    -p:x Port number to listen on/n");
printf("    -i:str Interface to listen on/n");
printf("    -o Dont't echo the data back/n");
printf("camel 2004-8-29");
ExitProcess(1);
}

// Function:
void ValidateArgs(int argc,char **argv)
{
int i;
for (i = 1; i < argc ;i++)
{
    if ((argv[i][0]=='-') || (argv[1][0]=='/') )
    {
      switch (tolower(argv[i][1]))
      {
        case 'p':
          iPort = atoi(&argv[i][3]);
          break;
        case 'i':
          bInterface = TRUE;
          if(strlen(argv[i]) > 3)
            strcpy(szAddress,&argv[i][3]);
          break;
  case 'o':
   bRecvOnly = TRUE;
   break;
        default:
           usage();
           break;
      }
    }
}

}

//
DWORD WINAPI ClientThread(LPVOID lpParam)
{
SOCKET sock = (SOCKET)lpParam;
char szBuff[DEFAULT_BUFFER];
int ret,
   nLeft,
   idx;
while(1)
{
    //perform a blocking recv() call
ret = recv(sock,szBuff,DEFAULT_BUFFER,0);
if (ret==0) //Graceful close
  break;
else if (ret==SOCKET_ERROR)
    {
   printf("recv() failed: %d/n",WSAGetLastError());
   break;
}
    szBuff[ret] = '/0';
printf("RECV:'%S'/n",szBuff);
//
//If we selected to echo the data back,do it
//
    if(!bRecvOnly)
    {
   nLeft = ret;
   idx = 0;
   //
   //Make sure we write all the data
   //
   while(nLeft > 0)
   {
     ret = send(sock,&szBuff[idx],nLeft,0);
  if (ret == 0)
    break;
  else if (ret == SOCKET_ERROR)
  {
    printf("send() failed: %d/n",WSAGetLastError());
    break;
  }
  nLeft -= ret;
  idx += ret;

}

}

}
return 0;

}

int main(int argc,char ** argv)
{
printf("Server.cpp/n");
WSADATA wsd;
SOCKET sListen,
      sClient;
int iAddrSize;
HANDLE hThread;
DWORD dwThreadId;
struct sockaddr_in local,client;
ValidateArgs(argc,argv);
if (WSAStartup(MAKEWORD(2,2),&wsd)!=0)
{
    printf("Failed to load Winsock!/n");
return 1;
}
//
//Create out listening socket
//
sListen = socket(AF_INET,SOCK_STREAM,IPPROTO_IP);
if (sListen == SOCKET_ERROR)
{
    printf("socket() failed: %d/n",WSAGetLastError());
return 1;
}
//Select the local interface,and bind to it
//
if(bInterface)
{
    local.sin_addr.s_addr = inet_addr(szAddress);
if(local.sin_addr.s_addr == INADDR_NONE)
  usage();
}
else
   local.sin_addr.s_addr = htonl(INADDR_ANY);
local.sin_family = AF_INET;
local.sin_port = htons(iPort);

if (bind(sListen,(struct sockaddr *)&local,sizeof(local)) == SOCKET_ERROR)
{
    printf("bing() failed: %d/n",WSAGetLastError());
return 1;
}
listen(sListen,8);
//
//In a continuous loop, wait for incoming clients.once one
//is detected,create a thread and pass the handle off to it.
//
while(1)
{
    iAddrSize = sizeof(client);
sClient = accept (sListen,(struct sockaddr *)&client,&iAddrSize);
    if(sClient == INVALID_SOCKET)
{
   printf("accept() failed:%d/n",WSAGetLastError());
   break;
}
    printf("Accepted client:%s:%d/n",inet_ntoa(client.sin_addr),ntohs(client.sin_port));

    hThread = CreateThread(NULL,0,ClientThread,(LPVOID)sClient,0,&dwThreadId);
if (hThread == NULL )
{
   printf("CreateThread() failed:%d /n",GetLastError());
   break;
}
    CloseHandle(hThread);

}
closesocket(sListen);
WSACleanup();

return 0;
}

//--------------------------------------------------------

在VC++6.0下编译时,由于对VC++的编译器不熟。开

始出现winsock api中的函数名不能解析的错误

...

error LNK2001: unresolved external symbol _inet_addr@4
error LNK2001: unresolved external symbol _htons@4
error LNK2001: unresolved external symbol _socket@12
...

通过在工程中加入ws2_32.lib,搞定。

project-->setting-->Link-->Object/Library modules 添加 ws2_32.lib