title: Transactional objects in pqxx
body: <p>I'm new in PostgreSQL and pqxx. I code in C++.
  I've just written an exemple program. Everythig is alright but when I execute my program I see an error : </p>
  
  <p>Started nontransaction while transaction still active.</p>
  
  <p>Here's the code : <a href="http://pastebin.com/p8CJ6Eaz" rel="nofollow">http://pastebin.com/p8CJ6Eaz</a></p>
  
  <p>If someone knows how to use those transactional objects please explain me. 
  Greetings to all and thanks for help. </p>