public function execArgv(array $argv = null)
    {
        try {
            $this->handleArgv($argv);
            // @codeCoverageIgnoreStart
        } catch (NoRouteFoundException $e) {
            fwrite(STDERR, 'Usage Error: ' . $e->getMessage() . PHP_EOL);

            // sysexits.h: #define EX_USAGE 64 /* command line usage error */
            exit(64);
        } catch (Exception $e) {
            fwrite(STDERR, 'Program Error: ' . $e->getMessage() . PHP_EOL);

            // stdlib.h: #define EXIT_FAILURE 1
            exit(1);
        }
        // @codeCoverageIgnoreEnd
    }