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PORequired and Optional Arguments Using Boost Library Program Options
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  1. PORequired and Optional Arguments Using Boost Library Program Options
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    copied!<p>I'm using Boost Program Options Library to parse the command line arguments.</p> <p>I have the following requirements:</p> <ol> <li>Once "help" is provided, all the other options are optional;</li> <li>Once "help" is not provided, all the other options are required.</li> </ol> <p>How I can deal with this? Here is the my code handling this, and I found it's very redundant, and I think there must be an easy to do, right?</p> <pre><code>#include &lt;boost/program_options.hpp&gt; #include &lt;iostream&gt; #include &lt;sstream&gt; namespace po = boost::program_options; bool process_command_line(int argc, char** argv, std::string&amp; host, std::string&amp; port, std::string&amp; configDir) { int iport; try { po::options_description desc("Program Usage", 1024, 512); desc.add_options() ("help", "produce help message") ("host,h", po::value&lt;std::string&gt;(&amp;host), "set the host server") ("port,p", po::value&lt;int&gt;(&amp;iport), "set the server port") ("config,c", po::value&lt;std::string&gt;(&amp;configDir), "set the config path") ; po::variables_map vm; po::store(po::parse_command_line(argc, argv, desc), vm); po::notify(vm); if (vm.count("help")) { std::cout &lt;&lt; desc &lt;&lt; "\n"; return false; } // There must be an easy way to handle the relationship between the // option "help" and "host"-"port"-"config" if (vm.count("host")) { std::cout &lt;&lt; "host: " &lt;&lt; vm["host"].as&lt;std::string&gt;() &lt;&lt; "\n"; } else { std::cout &lt;&lt; "\"host\" is required!" &lt;&lt; "\n"; return false; } if (vm.count("port")) { std::cout &lt;&lt; "port: " &lt;&lt; vm["port"].as&lt;int&gt;() &lt;&lt; "\n"; } else { std::cout &lt;&lt; "\"port\" is required!" &lt;&lt; "\n"; return false; } if (vm.count("config")) { std::cout &lt;&lt; "config: " &lt;&lt; vm["config"].as&lt;std::string&gt;() &lt;&lt; "\n"; } else { std::cout &lt;&lt; "\"config\" is required!" &lt;&lt; "\n"; return false; } } catch(std::exception&amp; e) { std::cerr &lt;&lt; "Error: " &lt;&lt; e.what() &lt;&lt; "\n"; return false; } catch(...) { std::cerr &lt;&lt; "Unknown error!" &lt;&lt; "\n"; return false; } std::stringstream ss; ss &lt;&lt; iport; port = ss.str(); return true; } int main(int argc, char** argv) { std::string host; std::string port; std::string configDir; bool result = process_command_line(argc, argv, host, port, configDir); if (!result) return 1; // Do the main routine here } </code></pre>
 

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