title: boost::system::(...)_category defined but not used
body: <p>I'm currently getting compiler warnings that resemble the warning I gave in the question title. Warnings such as....</p>
  
  <p><code>warning: 'boost::system::generic_category' defined but not used</code></p>
  
  <p><code>warning: 'boost::system::posix_category' defined but not used</code></p>
  
  <p><code>warning: 'boost::system::errno_ecat' defined but not used</code></p>
  
  <p><code>warning: 'boost::system::native_ecat' defined but not used</code></p>
  
  <p>As far as I know the program isn't being affected in any way. However, I don't like warnings hanging around, but I have no idea what these warnings are trying to tell me besides that something defined and related to boost is hanging around somewhere not being used. However, everything that I've defined, I've used. The boost libraries I'm using are the random library and the filesystem library.</p>
  
  <p>When I check the source of the warning it brings up Boost's error_category.hpp file and highlights some <code>static const</code>s that are commented as either "predefined error categories" or "deprecated synonyms". Maybe the problem has something to do with my error handling (or lack of) when using the library?</p>
  
  <p>Can anyone give some insight regarding why these warnings are popping up? Am I completely missing something? </p>
  
  <p>P.S. Warnings are at max level.</p>