title: is it valid to use standard library function name as identifier in C++?
body: <p>Consider following program:</p>
  
  <pre><code>#include &lt;cstdio&gt;
  int main()
  {
      int printf=9;
      std::printf("%d",printf);
  }
  </code></pre>
  
  <p>Is it fine to use built in function name as an identifier in variable declaration? Is this well defined program? I mean is behaviour of above program well defined? I am curious to know whether the C++ standard allows to use standard function names as identifiers of variables </p>