Linux 下socket编程客户端与服务端代码

客户端代码：

/* client */#include <stdio.h>#include <sys/types.h>#include <netinet/in.h>#include <sys/socket.h>#include <netdb.h>#include <unistd.h>#include <string.h>#include <arpa/inet.h>#include <errno.h>#define PORT 8848#define MAXDATASIZE 100int main(int argc, char *argv[]){   char hostname[100];   gethostname(hostname,sizeof(hostname));   printf("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~%s\n",hostname);    int sockfd, numbytes;    char buf[MAXDATASIZE];    struct hostent *he;    struct sockaddr_in serv_addr;    if (argc != 2)    {        fprintf(stderr, "usage: cilent hostname\n");        return 0;    }    if ((he = gethostbyname(argv[1])) == NULL)    {        fprintf(stderr, "gethostbyname error!\n");       return 0;;    }    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)    {        fprintf(stderr, "socket error!\n");       return 0;    }    serv_addr.sin_family = AF_INET;    serv_addr.sin_port = htons(PORT);    serv_addr.sin_addr = *((struct in_addr *)he->h_addr);    bzero(&(serv_addr.sin_zero), 8);    if (connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(struct sockaddr)) == -1)    {        fprintf(stderr, "connect error!\n");        return 0;    }    if ((numbytes = read(sockfd, buf, MAXDATASIZE)) == -1)    {        fprintf(stderr, "read error!\n");        return 0;    }    buf[numbytes] = '\0';    printf("Received: %s", buf);    close(sockfd);}

服务器端代码：

/* server */#include <stdio.h>#include <sys/types.h>#include <netinet/in.h>#include <sys/socket.h>#include <netdb.h>#include <unistd.h>#include <string.h>#include <arpa/inet.h>#include <sys/wait.h>#include <errno.h>#define PORT 8848#define BACKLOG 10int main(void){ int sockfd, conn_fd;    struct sockaddr_in my_addr;    struct sockaddr_in their_addr;    int sin_size;    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)    {        fprintf(stderr, "socket error!\n");       return 0;    }    my_addr.sin_family = AF_INET;    my_addr.sin_port = htons(PORT);    my_addr.sin_addr.s_addr = INADDR_ANY;    bzero(&(my_addr.sin_zero), 8);    if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1)    {        fprintf(stderr, "bind error!\n");           return 0;    }    if (listen(sockfd, BACKLOG) == -1)    {        fprintf(stderr, "listen error!\n");          return 0;    }    while (1)    {        sin_size = sizeof(struct sockaddr_in);        if ((conn_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1)        {            fprintf(stderr, "accept error!\n");            continue;        }        printf("server: got connection from %s\n", inet_ntoa(their_addr.sin_addr));        if (!fork())        {            if (send(conn_fd, "Hello, world!\n", 14, 0) == -1)                fprintf(stderr, "send error!\n");            close(conn_fd);            return 0;        }        close(conn_fd);        while(waitpid(-1, NULL, WNOHANG) > 0);    }}