title: Why doesn't free() zero out the memory prior to releasing it?
body: <p>When we <code>free()</code> memory in C, why is that memory not filled with zero? Is there a good way to ensure this happens as a matter of course when calling <code>free()</code>? </p>
  
  <p>I'd rather not risk leaving sensitive data in memory released back to the operating system...</p>