client.c

TCP/IP客户机程序简略实现

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <sys/socket.h>

#define SERVERPORT 3333
#define MAXSIZE 8192

int main(int argc,char *argv[])
{
    int fd, readsize;
    int sockfd, connectfd, sendbytes;
    char buf[MAXSIZE] = "hello";
    struct hostent *host;
    struct sockaddr_in server_addr;
    if(argc < 2) {
	printf("Please enter the server's hostname!\n");
	exit(1);
    }
    host = gethostbyname(argv[1]);
    if(host == NULL) {
	printf("gethostbyname error!!!\n");
	exit(1);
    }
    else
	printf("gethostbyname success!!!\n");
    sockfd = socket(AF_INET,SOCK_STREAM,0);
    if(sockfd == -1) {
	printf("Create a socket error!!!\n");
	exit(1);
    }
    else
	printf("sockfd success!!! sockfd = %d\n",sockfd);
    server_addr.sin_family=AF_INET;
    server_addr.sin_port=htons(SERVERPORT);
    server_addr.sin_addr=*((struct in_addr *)host->h_addr);
    memset(server_addr.sin_zero, 0, sizeof(server_addr.sin_zero));
    connectfd = connect(sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr));
    if(connectfd == -1) {
	printf("connect error!!!\n");
	exit(1);
    }
    else 
	printf("connect success!!!\n");
    fd = open("/home/hongzhi/UNIX/linux_code/10/client.c", O_RDONLY);
    do {	
	readsize = read(fd, buf, sizeof(buf));
	sendbytes = send(sockfd,buf,readsize,0);
	if(sendbytes == -1) {
	    printf("send error!!!\n");
	    exit(1);
	}
	else
	    if(sendbytes > 0)
		printf("send success!!! sendbytes = %d\n",sendbytes);
	    else
		printf("send end!!!\n");
	memset(buf, 0, sizeof(buf));
    } while(readsize > 0);
    close(sockfd);
    close(fd);
    return 0;
}