title: Why use one vs the other: `boost::shared_array` VS `boost::shared_ptr<std::vector>`?
body: <p>So to deal with large blobs of memory either for an image or similar there are clearly lots of options.</p>
  
  <p>Since I'm a fan of smart pointers and RAII I'm wondering about whether it's smarter to go with : </p>
  
  <ul>
  <li>a <code>shared_ptr</code> to a <code>std::vector</code> </li>
  </ul>
  
  <p>or </p>
  
  <ul>
  <li>to go with a <code>shared_array</code> pointing to a dynamically allocated array.</li>
  </ul>
  
  <p>What are the conceptual, practical, and performance implications of choosing one vs the other?</p>