CmdArgs  cmd( argv[ 0 ],
              std::cout,
              std::cerr );
bool help( false );
cmd.addOption( new Option< bool >( help,
                                    "-h",
                                    "Print this message",
                                    false ) );
bool printHeader( false );
cmd.addOption( new Option< bool >( printHeader,
                                    "-header",
                                    "Print the header and exit" ) );
cmd.addOption( new Option< std::string >( filename,
                                          "-f",
                                          "Set the output file name",
                                          true /** make this arg mandatory **/ ) );
cmd.addOption( new Option< int64_t >( length, 
                                      "-l",
                                      "Length of run" ) );
cmd.addOption( new Option< int64_t >( buff_size,
                                      "-b",
                                      "Buffer size" ) );
cmd.addOption( new Option< int64_t >( repeat,
                                      "-r",
                                      "Number of times to repeat simulation" ) );
/** give object command line **/
cmd.processArgs( argc, argv );
/** handle the user needing help **/
if( help )
{
   cmd.printArgs();
   exit( EXIT_SUCCESS );
}
/** 
 * to check and see if all mandatory args are set, add this code
 * which will print all mandatory args that are missing.
 */
if(! cmd.allMandatorySet() )
{ 
   //exit since well, mandatory args missing
   exit( EXIT_FAILURE );
}