tchtcpcli.c

通信程序

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

#define PORT 3490    /* the port client will be connecting to */

#define MAXDATASIZE 100 /* max number of bytes we can get at once */

int main(int argc, char *argv[])
{
	int sockfd, numbytes;  
	char buf[MAXDATASIZE];
	struct hostent *he;
	struct sockaddr_in their_addr; /* connector's address information */

	if (argc != 2) 
	{
	    fprintf(stderr,"usage: client hostname\n");
	    exit(1);
	}

	if ((he=gethostbyname(argv[1])) == NULL) 
	{  /* get the host info */
	    perror("gethostbyname error");
	    exit(1);
	}
	perror("gethostbyname sucess\n");

	if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) 
	{
	    perror("socket error");
	    exit(1);
	}
	perror("socket sucess\n");

	their_addr.sin_family = AF_INET;      /* host byte order */
	their_addr.sin_port = htons(PORT);    /* short, network byte order */
	their_addr.sin_addr = *((struct in_addr *)he->h_addr);
	bzero(&(their_addr.sin_zero), 8);     /* zero the rest of the struct */

	if (connect(sockfd, (struct sockaddr *)&their_addr, sizeof(struct sockaddr)) == -1) 
	{
	    perror("connect error");
	    exit(1);
	}
	perror("connect sucess\n");

	if ((numbytes=recv(sockfd, buf, MAXDATASIZE, 0)) == -1) 
	{
            perror("recv error");
            exit(1);
        }

        buf[numbytes] = '\0';

        printf("Received: %s",buf);

        close(sockfd);

        return 0;
}