title: Header contents in implicit block list?
body: <p>I know that when you <code>malloc()</code> space on the heap, you actually take more bytes than requested in order to make room for the header and to allow padding for alignment purposes.</p>
  
  <p>For example, if you call <code>malloc(41)</code>, you will get 48 bytes--4 bytes for the header and then 44 bytes of user space.</p>
  
  <p>My question is this: does the header store the size of the entire block (after additional padding and the header space is tacked on), or does it only contain an integer representing the size of the space that the user has access to?</p>
  
  <p>Thanks!</p>