used by https://holmeshe.me/network-essentials-setsockopt-SO_KEEPALIVE

keepalive-cli-2.c

…include

int main(int argc, char *argv[]) {
  int sfd, portno, n;
  struct sockaddr_in srvaddr;
  struct hostent *host;
  
  if (argc < 3) { fprintf(stderr,"usage: %s ip port\n", argv[0]); exit(0); }
  
  portno = atoi(argv[2]);
  sfd = socket(AF_INET, SOCK_STREAM, 0);
  if (sfd < 0) { perror("ERROR: socket()"); exit(0); }
  
  host = gethostbyname(argv[1]);
  if (host == NULL) { fprintf(stderr,"ERROR: host does not exist"); exit(0); }
  
  bzero((char *) &srvaddr, sizeof(srvaddr));
  srvaddr.sin_family = AF_INET;
  srvaddr.sin_port = htons(portno);
  bcopy((char *)host->h_addr, (char *)&srvaddr.sin_addr.s_addr, host->h_length);
  
  if (connect(sfd, (struct sockaddr *)&srvaddr, sizeof(srvaddr)) < 0) { perror("ERROR: connect()"); exit(0); }
  
  sleep(100000);
  
  return 0;
}