title: Should I consider memmove() O(n) or O(1)?
body: <p>this may be a silly question, but I want to calculate the complexity of one of my algorithms, and I am not sure what complexity to consider for the <a href="http://www.cplusplus.com/reference/clibrary/cstring/memmove/" rel="noreferrer">memmove()</a> function. </p>
  
  <p>Can you please help / explain ? </p>
  
  <pre><code>void * memmove ( void * destination, const void * source, size_t num );
  </code></pre>
  
  <p>So is the complexity O(num) or O(1). I suppose it's O(num), but I am not sure as I lack for now the understanding of what's going on under the hood. </p>