title: C++ languages extensions
body: <p>I already read the FAQ, and i think maybe this is a subjective question, but i need to ask.
  Does anyine knows what exactly (i mean formally) is a C++ language extensions.</p>
  
  <p>I already saw examples, like nvdia CUDA c ext, Avalon transaction-based c++ ext.</p>
  
  <p>So the point is something like a formal definition or so.</p>
  
  <p>thxs anyway.</p>