title: What's the proper way to set individual options with boost program_options?
body: <p>I want to set an individual option with the boost::program_options library. The documentation doesn't seem to cover this. The <code>variables_map</code> structure the library populates inherits a map, so adding the following to my program (seems to) work:</p>
  
  <pre><code>namespace boost {
      namespace program_options {
          template &lt;typename T&gt;
          void set_in_options(variables_map m, const std::string&amp; option_name, const T&amp; value) {
              m.insert(std::make_pair(option_name, variable_value(value, false)));
          }
          void set_in_options(variables_map m, const std::string&amp; option_name) {
              m.insert(std::make_pair(option_name, variable_value(true, false)));
          }
      }
  }
  </code></pre>
  
  <p>But surely the library author has some "right way" to do this?</p>