title: getchar_unlocked in windows undeclared
body: <p>Here is my code:</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  
  void scan(int* i)
  {
      int t=0;
      char c;
      bool negative=false;
      c=getchar_unlocked();
      while(c&lt;'0'&amp;&amp;c&gt;'9')
      {
          if(c=='-')
              negative=true;
          c=getchar_unlocked();
      }
      while(c&gt;'0'&amp;&amp;c&lt;'9')
      {
          t=(t&lt;&lt;3)+(t&lt;&lt;1)+c-'0';
          c=getchar_unlocked();
      }
      if(negative)
          t=~(t-1); //negative
      *i=t;
  }
  
  int main(int argc, char const *argv[])
  {
      int i;
      scan(&amp;i);
      return 0;
  }
  </code></pre>
  
  <p>I know that the function defined here as <code>scan</code> is faster than <code>scanf</code> and is very useful on programming competitions. But for some reason this code is not working on Windows and is working on Linux. What do I do to get it working on Windows? I am using the <code>g++</code> compiler from Dev-C++.</p>