title: Can someone provide an example of seeking, reading, and writing a >4GB file using boost iostreams
body: <p>I have read that boost iostreams supposedly supports 64 bit access to large files semi-portable way.  Their FAQ mentions <a href="http://www.boost.org/doc/libs/1_39_0/libs/iostreams/doc/faq.html#offsets" rel="noreferrer">64 bit offset functions</a>, but there is no examples on how to use them.  Has anyone used this library for handling large files?  A simple example of opening two files, seeking to their middles, and copying one to the other would be very helpful.</p>
  
  <p>Thanks.</p>