title: setvbuf() - size parameter when buf is NULL
body: <p>It seems that when I run the following code:</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  #include &lt;stdlib.h&gt;
  
  int main(int argc, char* argv)
  {
      int i=0;
  
      setvbuf(stdout, NULL, _IOLBF,0);
  
      while (1)
              printf("%d ",i++);
  
      return 0;
  }
  </code></pre>
  
  <p>it prints in chunks of 1024 chars, no matter the <strong>size</strong> I define for setvbuf().
  The question is is if <strong>size</strong> affects somehow in this case and where is the definition for 1024 chars is coming from.</p>