title: Need help understanding the meaning of "within a nested template argument list" error given by GCC
body: <p>This compiles:</p>
  
  <p><code>std::map&lt;int, std::vector&lt;int&gt; &gt; vDescriptorAtom;</code></p>
  
  <p>This:</p>
  
  <p><code>std::map&lt;int, std::vector&lt;int&gt;&gt; vDescriptorAtom;</code></p>
  
  <p>gives the following error:</p>
  
  <p><code>src/MessageHandler.cpp:191: error: &gt;&gt; should be &gt; &gt; within a nested template argument list</code></p>
  
  <p>This is obviously because <code>&gt;&gt;</code> is an operator. But looking at the error GCC throws, I cannot understand what it is trying to say. What does "nested template argument list" mean. Thanks. </p>