title: I'm trying to change pipe size using F_SETPIPE_SZ but when compiling it says it is undeclared?
body: <pre><code>#include &lt;unistd.h&gt;
  #include &lt;fcntl.h&gt;
  
  int exec[2];
  int pipesize = 8192;
  
  if(pipe(exec) ==-1) {
    perror("pipe");
    return -1;
  }
  
  fcntl(exec[1],F_SETPIPE_SZ,&amp;pipesize);
  </code></pre>
  
  <p>I'm running this code but i get an error saying F_SETPIPE_SZ is undeclared. I'm using Ubuntu 13.04, what may be the problem?</p>