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

nodelay-cli-1.c

...include

int main(int argc, char *argv[]) {
    int sfd, portno, n, delay;

    struct sockaddr_in srvaddr;
    struct hostent *host;

    char buffer[256] = "abc";
    if (argc < 3) { fprintf(stderr,"usage: %s ip port delay\n", argv[0]); exit(0); }

    portno = atoi(argv[2]);
    sfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sfd < 0) { perror("ERROR: socket()"); exit(0); }

    //int flags =1; 
    //if (setsockopt(sfd, SOL_TCP, TCP_NODELAY, (void *)&flags, sizeof(flags))) { perror("ERROR: setsocketopt(), TCP_NODELAY"); exit(0); }; 
 
    host = gethostbyname(argv[1]);
    if (host == NULL) { fprintf(stderr,"ERROR: host does not exist"); exit(0); }

    delay = atoi(argv[3]);

    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); }
 
    for (int i = 0; i < 1000; i++) {
      n = write(sfd, buffer, 4);
      if (n < 0) { perror("ERROR: writing()"); exit(0); }
      usleep(delay);
    }

    printf("finished\n");

    return 0;
}