#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>         /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define LISTEN_SZ 10

int main(int argc,char *argv[])
{
    if (argc != 3){
        fprintf(stderr,"usage : %s < ip > < port >.\n",argv[0]);
        exit(EXIT_FAILURE);
    }

    int sfd,ret,cfd;
    struct sockaddr_in  svr_addr,cli_addr;

    ssize_t sbytes,rbytes;
    char buffer[1024] = {0};

    sfd = socket(AF_INET,SOCK_STREAM,0);
    if (sfd == -1){
        perror("[ERROR] socket(): ");
        exit(EXIT_FAILURE);
    }

    bzero(&svr_addr,sizeof(struct sockaddr_in));
    svr_addr.sin_family = AF_INET;
    svr_addr.sin_port = htons(atoi(argv[2]));
    svr_addr.sin_addr.s_addr = inet_addr(argv[1]);
    
    ret = bind(sfd,(const struct sockaddr *)&svr_addr,sizeof(struct sockaddr_in));
    if (ret == -1){
        perror("[ERROR] bind(): ");
        close(sfd);
        exit(EXIT_FAILURE);
    }

    
    ret = listen(sfd,LISTEN_SZ);
    if (ret == -1){
        perror("[ERROR] listen(): ");
        close(sfd);
        exit(EXIT_FAILURE);
    }

    socklen_t len = sizeof(struct sockaddr_in);
    bzero(&cli_addr,sizeof(struct sockaddr));
    cfd = accept(sfd,(struct sockaddr *)&cli_addr,&len);
    if (cfd == -1){
        perror("[ERROR] accept(): ");
        exit(EXIT_FAILURE);
    }

    printf("ip : %s,port : %d\n",inet_ntoa(cli_addr.sin_addr),ntohs(cli_addr.sin_port));

    for(;;) {
        
        memset(buffer,sizeof(buffer),0);
        rbytes = recv(cfd,buffer,sizeof(buffer),0);
        if (rbytes == -1){
            perror("recv(): ");
            
            exit(EXIT_FAILURE);
        }else if (rbytes == 0){
            printf("The client is offline.\n");
            
            exit(EXIT_FAILURE);

        }else if (rbytes > 0){

            printf(" %s\n",buffer);

        }

        sleep(1);// 服务器间隔 1s 接收一次数据
    }
    
    close(cfd);
    close(sfd);
    return 0;
}

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>

#include <sys/types.h>         /* See NOTES */
#include <sys/socket.h>

int main(int argc,char *argv[])
{
    int sfd,ret;    
    ssize_t sbytes = 0,rbytes = 0;
    char sbuffer[1024] = {0};
    char rbuffer[1024] = {0};

    struct sockaddr_in svr_addr;
    if (argc != 3){
        fprintf(stderr,"Usage : %s < ip > < port >.\n",argv[0]);
        return -1;
    }

    sfd = socket(AF_INET,SOCK_STREAM,0);
    if (sfd == -1){
        perror("[ERROR] socket(): ");
        exit(EXIT_FAILURE);
    }
    
    printf("sfd = %d\n",sfd);
    bzero(&svr_addr,sizeof(svr_addr));
    svr_addr.sin_family = AF_INET;
    svr_addr.sin_port = htons(atoi(argv[2]));
    svr_addr.sin_addr.s_addr = inet_addr(argv[1]);
    
    ret = connect(sfd,(const struct sockaddr *)&svr_addr,sizeof(struct sockaddr));
    if (ret == -1){
        perror("[ERROR] connect():");
        exit(EXIT_FAILURE);
    }
    
    for(;;){

        strcpy(sbuffer,"hello,abcde");

        sbytes = send (sfd,sbuffer,strlen(sbuffer),0); 

        if (sbytes == -1){
            perror("[ERROR] send(): ");
            exit(EXIT_FAILURE);
        }

        usleep(100);
    }
    

    
    close(sfd);
    return 0;
}

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