title: Is the return value of malloc a virtual or physical address?
body: <p>Is the address returned by malloc a virtual address or is it the actual physical address where the memory is allocated?</p>
  
  <p><strong>Edit:</strong></p>
  
  <p>I read somewhere "In some implementations, calling free() releases the memory back to the system and in others it is released back to the process". Does "releasing back to the system" imply that the memory is the actual physical memory and "releasing back to the process" mean it is virtual memory?</p>