linux socket编程之多路复用select的例子

虚拟机:centos6.5

功能：可实现多个客户端连接服务器端，并实现收发数据

#include 
#include 
#include 
#include 

#include 
#include 
#include 

#define TURE      0
#define FALSE     -1
#define SER_PORT  2345
#define BUF_SIZE  1024
#define MAXLINE   80

int main(void)
{
    int       i, j, n, maxi, maxfd, nret, sin_size;
    int       listen_fd, connect_fd;
	int       client[FD_SETSIZE];
    char      buf[BUF_SIZE], addr_p[20];
	fd_set    rset, fds;

    struct sockaddr_in      ser_addr, cli_addr;
	struct timeval          timeout={100,0};

	sin_size=sizeof(struct sockaddr_in);

    bzero(&ser_addr, sizeof(ser_addr));
    ser_addr.sin_family=AF_INET;
    ser_addr.sin_addr.s_addr=htonl(INADDR_ANY);
    ser_addr.sin_port=htons(SER_PORT);

    listen_fd=socket(AF_INET, SOCK_STREAM, 0);
    if(listen_fd < 0)
    {
	    perror("socket fail");
	    return FALSE;
    }
    
    if( (bind(listen_fd, (struct sockaddr*)&ser_addr, sizeof(ser_addr))) < 0)
    {
	    perror("bind fial");
	    return FALSE;
    }

    if ( (listen(listen_fd, 20)) <0 )
    {
	    perror("listen fail");
	    return FALSE;
    }

	maxfd = listen_fd;     
	maxi = -1;            
	for (i = 0; i < FD_SETSIZE; i++)
	{
		client[i] = -1;  
	}

    FD_ZERO(&fds);
	FD_SET(listen_fd,&fds);

    while(1)
    {
		timeout.tv_sec=100;
		timeout.tv_usec=0;
		rset=fds;

		nret = select(maxfd+1, &rset, NULL, NULL, &timeout);
		if(nret<0)
		{
			perror("select error");
            return -1;
		}

	    for(i=0; i<=maxfd; i++)
		{
		    if( !FD_ISSET(i, &rset) )
		    {
				printf("i=%d\n",i);
				continue;
			}



			if(i==listen_fd)
			{
				printf("listen_fd=%d,i=%d\n", listen_fd, i);

				if ((connect_fd=accept(listen_fd, (struct sockaddr*)&cli_addr, &sin_size)) <0 )
			    {
				    perror("accept fail");
				    continue;
	            }	
			    else
			    {
					inet_ntop(AF_INET,&cli_addr.sin_addr,addr_p,sizeof(addr_p));
					printf("fd%d is connect, ip: %s, port: %d\n", connect_fd, addr_p, ntohs(cli_addr.sin_port));
			    }

			    for(j = 0; j < FD_SETSIZE; j++)
			    {
			        if(client[j] < 0)
				    {
					    client[j] = connect_fd;
					    break;
				    }

			    }
				printf("client[%d]=%d\n", j, connect_fd);

			    if( i == FD_SETSIZE )
			    {
				    close(connect_fd);
				    continue;
			    }

			    FD_SET(connect_fd, &fds);

			    if (connect_fd > maxfd) 
			    {
				    maxfd = connect_fd;                              
			    }

			    if (j > maxi)  
			    {
				    maxi = j;
				    printf("Amount %d client connect\n", maxi+1);
			    }

			}
			else
			{
				printf("fd%d is send data \n",i);
				
				if ( (n = read(i, buf, MAXLINE)) < 0)
				{
				   printf("read fd%d fail\n",i);
				   continue;
			    }
		        else
			    {
				    printf("read fd%d %d size:%s\n", i, n, buf);
			    }

				if( (n=write(i, addr_p, sizeof(addr_p))) <0 )
				{
					perror("write fail");
					continue;
				}
				else
				{
					printf("write %d size\n",n);
				}
		   
			}
	
		}
	}

    close(listen_fd);
    return;
}

/* Some Unix Program Standard head file  */
#include 
#include 
#include 
#include 

/* Socket Program head file */
#include 
#include   
#include   /* sockaddr_in{} and other Internet define */
#include    /* For inet_pton() */

#include    /* strerror(), perror(), errno head file*/

#define SERV_PORT 2345
#define SER_IP  "192.168.199.109"
#define BUF_SIZE 512


/* Argc is the program linux running command arguments count, and argv is  
 * the arguments string value. All of the arguments take as string.
 * For example:
 * If we run this program as "./socket_client 192.168.3.15", there are two 
 * arguments, so argc=2, argv[0] is the first argument, which is string  value 
 * "./socket_client" and argv[1] is the second argment, which is string  value 
 * "1921.68.3.15". */
int main(int argc, char **argv)
{

	int                      cli_fd;
        struct sockaddr_in       ser_addr;
        int                      retval,nread,nwrite;
        char                     buf[BUF_SIZE];

     /* Check the arguments count, if No serverip address give as an argument,      
      * then program exit    
      if(2 != argc)     
      {        
	      printf("usage: %s \n", argv[0]);        
	      return -1;   
      }
     */


      if((cli_fd=socket(AF_INET,SOCK_STREAM,0))<0)
      {
             perror("socket fail");
             return -1;
      }


      memset(&ser_addr, 0, sizeof(ser_addr));
      ser_addr.sin_family=AF_INET;
      ser_addr.sin_addr.s_addr=inet_addr(SER_IP);
      ser_addr.sin_port=htons(SERV_PORT);

     /*
      if (inet_pton(AF_INET, argv[1], &ser_addr.sin_addr) <= 0)     
      {       
	    printf("Use inet_pton() to set the Server IP address failure.\n");       
  	    retval = -2;       
         // goto CleanUp;
      }
     */

     if((connect(cli_fd,(struct sockaddr*)&ser_addr,sizeof(struct sockaddr)))<0)
     {
           perror("connect fail");
           return -1;
     }

     while(1)
    { 
           memset(buf,0,sizeof(buf));
		   strcpy(buf,"hello");
           nwrite=write(cli_fd,buf,strlen(buf));
          if(nwrite<0)
          {
	         perror("write fail");
	         return -1;
          }
          else
          {
	         printf("write %d size:%s\n", nwrite, buf);
          }
		

		  memset(buf,0,sizeof(buf));
		  nread=read(cli_fd,buf,sizeof(buf));
		  if(nread<0)
		  {
			  perror("read fail");
			  return -1;
		  }
		  else
		  {
			  buf[nread]=0;
			  printf("read %d size\n",nread);
			   printf("read data :%s\n",buf);
		  }

    
		  sleep(2);
    }

    close(cli_fd);
    return;

}