title: Difference(s) between flushall() and _flushall()
body: <p>The compiler (Visual C++) always corrects me when I type <code>flushall();</code></p>
  
  <blockquote>
    <p>warning C4996: 'flushall': The POSIX name for this item is deprecated. Instead, use the ISO C++ conformant name: _flushall.</p>
  </blockquote>
  
  <p>They both work for me, is there any difference?</p>