client_tst.c

/*** clientprog.c ****/
/*** a stream socket client demo ***/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
 
// the port client will be connecting to
//#define PORT 5678
// max number of bytes we can get at once
// gcc -g client_tst.c -o  client_tst

#define MAXDATASIZE 300
 
int main(int argc, char *argv[])
{

  int PORT=atoi(argv[2]);
int sockfd, numbytes;
char buf[MAXDATASIZE];

struct timeval tv;
tv.tv_sec = 3;  /* 30 Secs Timeout */
tv.tv_usec = 0;  // Not init'ing this can cause strange errors

struct hostent *he;
// connector’s address information
struct sockaddr_in their_addr;
 
// if no command line argument supplied
if(argc != 3)
{
    fprintf(stderr, "Client-Usage: %s the_client_hostname  port\n", argv[0]);
    // just exit
    exit(1);
}
 
// get the host info
if((he=gethostbyname(argv[1])) == NULL)
{
    perror("gethostbyname()");
    exit(1);
}
else
    printf("Client-The remote host is: %s\n", argv[1]);
 
if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
    perror("socket()");
    exit(1);
}
else
 setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,sizeof(struct timeval));
    printf("Client-The socket() sockfd is OK... timeout 3s\n");

// host byte order
their_addr.sin_family = AF_INET;
// short, network byte order
printf("Server-Using %s and port %d...\n", argv[1], PORT);
their_addr.sin_port = htons(PORT);
their_addr.sin_addr = *((struct in_addr *)he->h_addr);
// zero the rest of the struct
memset(&(their_addr.sin_zero), '\0', 8);
 

if(connect(sockfd, (struct sockaddr *)&their_addr, sizeof(struct sockaddr)) == -1)
{
    perror("connect()");
    exit(1);
}
else
    printf("Client-The connect() is OK...\n");
 
if((numbytes = recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1)
{
    printf("recv - bytes = %d\n", numbytes);

        perror("recv() ... my...");
    //    exit(1);
}
 else{
  printf("Client-The recv() is OK...  bytes = %d\n", numbytes);
 
buf[numbytes] = '\0';
printf("Client-Received: %s", buf);
 }
printf("Client-Closing sockfd\n");
close(sockfd);
return 0;
}