Is new C++ backward compatible
<p>I haven't coded in C++ for years. I recently discovered that during those years it has changed quite dramatically. I'm not sure I like the changes, but that's another discussion.</p>

<p>I still have some C++ code knocking around my hard drive. If I got it out and tried to compile it with a nice new C++ compiler, say the latest version of g++, would it compile? Without warnings (assuming it compiled without warnings before)?</p>

<p>I did get to mess around with a little VC++ 2010 recently and found some things I expected to work just not working, and got different messages depending on context when I tried to use NULL. But in one part of that code I used NULL without even a warning.</p>
