VC中Socket通信基础

1.客户端程序
SocketClientBlock.c

#pragma comment(lib, "WS2_32")

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

#define BUF_SIZE (1024)

int main(int argc,char **argv) 
{
  WSADATA wsadata;

  int  sockfd,n;
  char  receline[BUF_SIZE];
  struct  sockaddr_in serveraddr;

  //Winsows下启用socket
  if(WSAStartup(MAKEWORD(1,1),&wsadata)==SOCKET_ERROR)
  {
    printf("WSAStartup() fail\n");
    exit(0);
  }

  //建立socket
  if((sockfd=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP))==SOCKET_ERROR)
  {
    printf("socket() fail\n");
    exit(0);
  }

  //设置协议,IP及Port
  memset(&serveraddr,0,sizeof(serveraddr));
  serveraddr.sin_family = AF_INET;
  serveraddr.sin_port=htons(1024);
  serveraddr.sin_addr.s_addr=inet_addr("127.0.0.1");
  /*
  //hostname转ip
  hostent *hostEnt = gethostbyname( strRemote );
  if( hostEnt != NULL )
  {
    lIPAddress = ((in_addr*)hostEnt->h_addr)->s_addr;
    serveraddr.sin_addr.s_addr = lIPAddress;
  }
  else
  {
    serveraddr.sin_addr.s_addr = inet_addr( strRemote );
  }
  */

  //连接
  if(connect(sockfd,(struct sockaddr *)&serveraddr,sizeof(serveraddr))==SOCKET_ERROR)
  {
    printf("connect() fail\n");
    exit(0);
  }

  //读取数据并输入到标准输出
  while((n=recv(sockfd,receline,BUF_SIZE,0))!=SOCKET_ERROR)
  { 
    receline[n]=0;
    if(fputs(receline,stdout)==EOF)
    {
      printf("fputs() error\r\n");
    }
  }

  //没有获取数据
  if(n<0) 
  {
    printf("read() fail\n");
  }

  //Winsows下关闭socket
  closesocket(sockfd);
  WSACleanup();

  exit(0);
}
&#91;/code&#93;

2.服务端程序，阻塞
SocketServerBlock.c
&#91;code lang="c"&#93;
#pragma comment(lib, "WS2_32")

#include <winsock.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define MAX_CONNECT_NUM (10)

int main(int argc,char** argv)
{
  WSADATA wsadata;
  struct  sockaddr_in serveraddr;
  int  socketflag,connectflag;

  time_t  time_tick;
  char  buff[1024];
  
  //Winsows下启用网络
  if(WSAStartup(MAKEWORD(1,1),&wsadata)==SOCKET_ERROR)
  {
    printf("WSAStartup() fail,%d\n", WSAGetLastError());
    exit(0);
  }
  
  //新建socket
  if(INVALID_SOCKET==(socketflag=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP)))
  {
    printf("socket() fail\n");
    exit(0);
  }

  //清零,设置协议,设置IP,设置Port
  memset(&serveraddr,0,sizeof(serveraddr));
  serveraddr.sin_family=AF_INET;
  serveraddr.sin_addr.s_addr=htonl(INADDR_ANY);
  serveraddr.sin_port=htons(1024);

  //绑定端口，监听1024端口的任何请求
  if(SOCKET_ERROR==bind(socketflag,(struct sockaddr*)&serveraddr,sizeof(serveraddr)))
  {
    printf("bind() fail\n");
    exit(0);
  }

  //监听端口，最大并发数MAX_CONNECT_NUM
  if(SOCKET_ERROR==listen(socketflag,MAX_CONNECT_NUM))
  {
    printf("listen() fail\n");
    exit(0);
  }

  //接受请求，发送主机时间
  for(;;)
  {
    struct  sockaddr clientaddr;
    int iLen = sizeof(clientaddr);
    printf("Waiting for connection...\n");

    //接受连接
    connectflag=accept(socketflag,&clientaddr,&iLen);
    if(INVALID_SOCKET==connectflag)
    {
      printf("accept() fail\n");
      exit(0);
    }

    //获取时间，并格式化
    time_tick=time(NULL);
    sprintf(buff,"From mys:\n%s",ctime(&time_tick));
    //写入时间
    if(SOCKET_ERROR==send(connectflag,buff,strlen(buff),0))
    {
      printf("send() fail\n");
      exit(0);
    }

    //关闭连接
    closesocket(connectflag);
  }

  //Winsows下关闭socket及网络
  if(SOCKET_ERROR==closesocket(socketflag))
  {
    printf("closesocket() fail\n");
    exit(0);
  }
  WSACleanup();

  //退出
  exit(0);
}

3.服务端程序，阻塞，有Select
SocketServerBlockSelect.c

#pragma comment(lib, "WS2_32")

#include <winsock.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define MAX_CONNECT_NUM (10)

int main(int argc,char** argv)
{
  WSADATA wsadata;
  struct  sockaddr_in serveraddr;
  int  socketflag,connectflag;

  fd_set  fdR;
  struct  timeval timeout ={1,500};

  time_t  time_tick;
  char  buff[1024];
  
  //Winsows下启用网络
  if(WSAStartup(MAKEWORD(1,1),&wsadata)==SOCKET_ERROR)
  {
    printf("WSAStartup() fail,%d\n", WSAGetLastError());
    exit(0);
  }
  
  //新建socket
  if(INVALID_SOCKET==(socketflag=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP)))
  {
    printf("socket() fail\n");
    exit(0);
  }

  //清零,设置协议,设置IP,设置Port
  memset(&serveraddr,0,sizeof(serveraddr));
  serveraddr.sin_family=AF_INET;
  serveraddr.sin_addr.s_addr=htonl(INADDR_ANY);
  serveraddr.sin_port=htons(1024);

  //绑定端口，监听1024端口的任何请求
  if(SOCKET_ERROR==bind(socketflag,(struct sockaddr*)&serveraddr,sizeof(serveraddr)))
  {
    printf("bind() fail\n");
    exit(0);
  }

  //监听端口，最大并发数MAX_CONNECT_NUM
  if(SOCKET_ERROR==listen(socketflag,MAX_CONNECT_NUM))
  {
    printf("listen() fail\n");
    exit(0);
  }

  //接受请求，发送主机时间
  for(;;)
  {
    printf("Waiting for connection...\n");

    FD_ZERO(&fdR);
    FD_SET(socketflag, &fdR);
        switch (select(0, &fdR, NULL, NULL,&timeout)) 
    {
    case SOCKET_ERROR:
      printf("Socket Error...\n");
      break;
    case 0:
      printf("Time Out Here...\n");
      break;
    default:
      printf("Connection is coming...\n");
      if (1)
      {
        struct  sockaddr clientaddr;
        int iLen = sizeof(clientaddr);

        //接受连接
        connectflag=accept(socketflag,&clientaddr,&iLen);
        if(INVALID_SOCKET==connectflag)
        {
          printf("accept() fail\n");
          exit(0);
        }

        //获取时间，并格式化
        time_tick=time(NULL);
        sprintf(buff,"From mys:\n%s",ctime(&time_tick));
        //写入时间
        if(SOCKET_ERROR==send(connectflag,buff,strlen(buff),0))
        {
          printf("send() fail\n");
          exit(0);
        }

        //关闭连接
        closesocket(connectflag);
      }
      break;
        }
  }

  //Winsows下关闭socket及网络
  if(SOCKET_ERROR==closesocket(socketflag))
  {
    printf("closesocket() fail\n");
    exit(0);
  }
  WSACleanup();

  //退出
  exit(0);
}

4.服务端程序，非阻塞
SocketServerNonBlock.c

#pragma comment(lib, "WS2_32")

#include <winsock.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define MAX_CONNECT_NUM (10)

int main(int argc,char** argv)
{
  WSADATA wsadata;
  struct  sockaddr_in serveraddr;
  int  socketflag,connectflag;

  time_t  time_tick;
  char  buff[1024];

  unsigned long flag=1;
  
  //Winsows下启用网络
  if(WSAStartup(MAKEWORD(1,1),&wsadata)==SOCKET_ERROR)
  {
    printf("WSAStartup() fail,%d\n", WSAGetLastError());
    exit(0);
  }
  
  //新建socket
  if(INVALID_SOCKET==(socketflag=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP)))
  {
    printf("socket() fail\n");
    exit(0);
  }

  //非阻塞方式
  if(ioctlsocket(socketflag,FIONBIO,&flag)!=0)
  {
    printf("ioctlsocket() fail\n");
    exit(0);
  }

  //清零,设置协议,设置IP,设置Port
  memset(&serveraddr,0,sizeof(serveraddr));
  serveraddr.sin_family=AF_INET;
  serveraddr.sin_addr.s_addr=htonl(INADDR_ANY);
  serveraddr.sin_port=htons(1024);

  //绑定端口，监听1024端口的任何请求
  if(SOCKET_ERROR==bind(socketflag,(struct sockaddr*)&serveraddr,sizeof(serveraddr)))
  {
    printf("bind() fail\n");
    exit(0);
  }

  //监听端口，最大并发数MAX_CONNECT_NUM
  if(SOCKET_ERROR==listen(socketflag,MAX_CONNECT_NUM))
  {
    printf("listen() fail\n");
    exit(0);
  }

  //接受请求，发送主机时间
  for(;;)
  {
    struct  sockaddr clientaddr;
    int iLen = sizeof(clientaddr);
    printf("Waiting for connection...\n");

    //接受连接
    connectflag=accept(socketflag,&clientaddr,&iLen);
    if(INVALID_SOCKET==connectflag)
    {
      printf("no connection\n");
      Sleep(1500);
    }
    else
    {
      printf("Connection is coming...\n");
      //获取时间，并格式化
      time_tick=time(NULL);
      sprintf(buff,"From mys:\n%s",ctime(&time_tick));
      //写入时间
      if(SOCKET_ERROR==send(connectflag,buff,strlen(buff),0))
      {
        printf("send() fail\n");
        exit(0);
      }

      //关闭连接
      closesocket(connectflag);
    }
  }

  //Winsows下关闭socket及网络
  if(SOCKET_ERROR==closesocket(socketflag))
  {
    printf("closesocket() fail\n");
    exit(0);
  }
  WSACleanup();

  //退出
  exit(0);
}