Socket——实现简单的一对一服务器端与客户端聊天功能

server.c

/* Socket head file */#include<sys/types.h>#include<sys/socket.h>#include<netinet/in.h>/*sockaddr_in{} */#include<arpa/inet.h>/* Unix standard head file */#include<stdio.h>#include<stdlib.h>#include<string.h>#include<unistd.h>#include <errno.h>/*strerror(),perror(),errno head file*/#include <sys/time.h>#include <sys/wait.h> #define PORT     9999#define MAX_BUFF 1024#define LISTENQ  1024int main (int argc, char **argv){    int sockfd;    int new_fd;    socklen_t len;    int retval;    int maxfd = -1;    unsigned int value = 1;    fd_set rfds;     struct sockaddr_in my_addr;    struct sockaddr_in t_addr;    struct timeval tv;    int my_port;    char buf[MAX_BUFF];    if(2 == argc)    {        my_port = atoi(argv[1]);    }    else    {        my_port = PORT;    }    /* Use Socket() function*/    if((sockfd = socket(AF_INET,SOCK_STREAM,0))<0)    {        perror("Socket error");        exit(1);    }    memset(&my_addr,0,sizeof(my_addr));    my_addr.sin_family = AF_INET;    my_addr.sin_port = htons(my_port);    my_addr.sin_addr.s_addr = INADDR_ANY;    /*Use bind() function*/    setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,(void *)&value,sizeof(value));     if(bind(sockfd,(struct sockaddr *)&my_addr,sizeof(my_addr))<0)    {        perror("bind error");        exit(1);    }    /* Use listen() function */    if(listen(sockfd,LISTENQ)<0)    {        perror("listen error");        exit(1);    }    /* Start to connect... */    while(1)    {        printf("waiting for new connecting to start new char:\n");        len = sizeof(struct sockaddr);        if((new_fd = accept(sockfd,(struct sockaddr *)&t_addr,&len))<0)        {            perror("accept error");            exit(errno);        }        else        {            printf("server got connection from:%s,por t%d,socked %d\n",inet_ntoa(t_addr.sin_addr),ntohs(t_addr.sin_port),new_fd);        }        /* Start processing the data on new connection */        while(1)        {               /* Set empty */            FD_ZERO(&rfds);            /* Add the standard input handle 0 */            FD_SET(0,&rfds);            maxfd = 0;            /*Add the current connection handle new_fd */            FD_SET(new_fd,&rfds);            if(new_fd > maxfd)            {                maxfd = new_fd;            }            /* Set maximum waiting time */            tv.tv_sec = 1;            tv.tv_usec = 0;            retval = select(maxfd+1,&rfds,NULL,NULL,&tv);            if(retval < 0)            {                printf("select error!%s\n",strerror(errno));                break;            }            else if(retval == 0)            {                continue;            }            else            {                if(FD_ISSET(new_fd,&rfds))/* Determine whether the state of the FD in the fdset collection is changing. */                {                    /* If there is message, accept and display */                    memset(&buf,0,sizeof(buf));                    /* Receive messages sent from the other, up to MAX_BUFF bytes */                    len = recv(new_fd,buf,MAX_BUFF,0);                    if(len > 0)                    {                        printf("Receive message success: %s \n",buf);                    }                    else                    {                        if(len < 0)                        {                            printf("Receive message fail,error is %s.\n",errno,strerror(errno));                        }                        else                            printf("quit\n");                        break;                    }                }//FD_ISSET = Socket                if(FD_ISSET(0,&rfds))                {                    memset(&buf,0,sizeof(buf));                    read(0,buf,MAX_BUFF);                    len = send(new_fd,buf,strlen(buf)-1,0);                    if(len < 0)                    {                        printf("error!\n");                        break;                    }                    else                    {                        printf("messages success!\n %s",buf);                    }                }//FD_ISSET = 0            }        }//End of second while        close(new_fd);    }//End of frist while    close(sockfd);    return 0;} /* ----- End of main() ----- */

client.c

/*  Socket head file */#include<sys/types.h>#include<sys/socket.h>#include<netinet/in.h>/*sockaddr_in{}*/#include<arpa/inet.h>/*  Unix standard head file */#include<stdio.h>#include<stdlib.h>#include<string.h>#include<unistd.h>#include <errno.h>/* strerror(),perror(),errno head file*/#include <sys/time.h>#include <sys/wait.h>#define MAXBUFF 1024 #define PORT 9999/******************************************************************************** *  Description: *   Input Args: *  Output Args: * Return Value: ********************************************************************************/int main (int argc, char **argv){    int sockfd;    int len;    int retval;    int maxfd = -1;    fd_set rfds;    struct sockaddr_in dest;    struct timeval tv;    char buff[MAXBUFF];    if(2 != argc)    {        printf("input error");        return -1;    }    /* Use Socket() function */    if((sockfd = socket(AF_INET,SOCK_STREAM,0))<0)    {        perror("Socket error");        exit(errno);    }    /*Initialize the address and port information of the server */    memset(&dest,0,sizeof(dest));    dest.sin_family = AF_INET;    dest.sin_port = htons(PORT);    if(inet_pton(AF_INET,argv[1],&dest.sin_addr)<=0)    {        perror("inet_pton() to set IP address failure");        exit(1);    }    /* connect to server */    printf("Connect to server[%s:%d]\n",argv[1],PORT);    if(connect(sockfd,(struct sockaddr *)&dest,sizeof(dest))<0)    {        perror("connect error");        exit(errno);    }    printf("\nReady to chatting...\n");    while(1)    {         /*  Set empty */        FD_ZERO(&rfds);        /*  Add the standard input handle 0 */        FD_SET(0,&rfds);         maxfd = 0;        /* Add the current connection handle new_fd */         FD_SET(sockfd,&rfds);         if(sockfd > maxfd)         {             maxfd = sockfd;         }        /*  Set maximum waiting time */         tv.tv_sec = 1;         tv.tv_usec = 0;        /* Start to wait */         retval = select(maxfd + 1,&rfds,NULL,NULL,&tv);         if(retval < 0)         {             printf("select error\n");             break;         }         else if(retval == 0)         {            continue;         }         else         {             if(FD_ISSET(sockfd,&rfds))/* Determine whether the state of the FD in the fdset collection is changing. */             {                memset(&buff,0,sizeof(buff));                /* Receive messages sent from the other, up to MAX_BUFF bytes */                len = recv(sockfd,buff,MAXBUFF,0);                if(len > 0)                {                    printf("Receive messages success: %s \n",buff);                }                else                {                    if(len < 0)                    {                        printf("Receive messages fail,error is:%s.\n",errno,strerror(errno));                    }                    else                        printf("quit\n");                    break;                }             }//FD_ISSET = sockfd             if(FD_ISSET(0,&rfds))             {                memset(&buff,0,sizeof(buff));                read(0,buff,MAXBUFF);                len = send(sockfd,buff,strlen(buff)-1,0);                if(len < 0)                {                    printf("Send error\n");                    break;                }                else                {                    printf("Send messages success!\n %s...\n",buff);                }             }//FD_ISSET = 0         }//select finished    }//End of while    close(sockfd);    return 0;} /* ----- End of main() ----- */

其中在client.c使用了select()函数。
测试结果：