title: Is it safe for multiple threads to call the same function?
body: <p>Is it safe to for example do:</p>
  
  <pre><code>void AddTwo(int &amp;num)
  {
    num +=2;
  }
  
  
  void ThreadProc(lpvoid arg)
  {
  AddTwo((int)arg);
  
  }
  </code></pre>
  
  <p>Would it be safe for this to occur if 4 threads were doing this at the same time? Thanks</p>