title: Specifying STL Map key with 3 components
body: <p>I am fairly new to STL. So pardon me if the question is naive.</p>
  
  <p>I have a pair like this that is used as a key to a map.</p>
  
  <p><code>typedef pair &lt;int, int&gt; KeyPair;</code></p>
  
  <p>My map is as shown below</p>
  
  <p><code>typedef map &lt;KeyPair, uint32&gt; NvInfoMap;</code></p>
  
  <p><strong>Now I want to introduce a new integer into the Key part of the map.</strong> </p>
  
  <p>Which is the easiest way to do this?</p>
  
  <p>Do I have to make another pair that will take the existing pair as its latter part?</p>
  
  <p>Please note that I am on a restricted environment where boost library is not available.</p>
  
  <p>Thanks for your time.</p>