How do I use TCP_NODELAY?

How do I use TCP_NODELAY? 

  First off, be sure you really want to use it in the first place.  It
  will disable the Nagle algorithm (see ``2.11 How can I force a socket
  to send the data in its buffer?''), which will cause network traffic
  to increase, with smaller than needed packets wasting bandwidth.
  Also, from what I have been able to tell, the speed increase is very
  small, so you should probably do it without TCP_NODELAY first, and
  only turn it on if there is a problem.

  Here is a code example, with a warning about using it from Andrew
  Gierth:

         int flag = 1;
         int result = setsockopt(sock,            /* socket affected */
                                 IPPROTO_TCP,     /* set option at TCP level */
                                 TCP_NODELAY,     /* name of option */
                                 (char *) &flag,  /* the cast is historical
                                                         cruft */
                                 sizeof(int));    /* length of option value */
         if (result < 0)
            ... handle the error ...

  TCP_NODELAY is for a specific purpose; to disable the Nagle buffering
  algorithm. It should only be set for applications that send frequent
  small bursts of information without getting an immediate response,
  where timely delivery of data is required (the canonical example is
  mouse movements).

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