title: Placement and non-placement allocators
body: <p>What are the placement and non-placement allocation/deallocation function? I've been reading <strong>sec. 3.7.4.2</strong> of N3797 and come across with the <strong>placement</strong> and <strong>non-placement</strong> <strong>allocation</strong>/<strong>deallocation</strong> function concepts. For instance:</p>
  
  <blockquote>
    <p>The global operator delete with exactly one parameter is a usual
    (<strong>non-placement</strong>) deallocation function.</p>
  </blockquote>
  
  <p>I could not find a definition of these concepts and I assume that non-placement is the functions which have one of the following signature:</p>
  
  <pre><code>void* operator new(std::size_t);
  void* operator new[](std::size_t);
  void operator delete(void*);
  void operator delete[](void*);
  void operator delete(void*, std::size_t) noexcept;
  void operator delete[](void*, std::size_t) noexcept;
  </code></pre>
  
  <p>Have I understood correctly?</p>