exit_codes.hpp

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#ifndef LIBJMMCG_CORE_EXIT_CODES_HPP
#define LIBJMMCG_CORE_EXIT_CODES_HPP
 
/******************************************************************************
** Copyright © 2016 by J.M.McGuiness, coder@hussar.me.uk
**
** This library is free software; you can redistribute it and/or
** modify it under the terms of the GNU Lesser General Public
** License as published by the Free Software Foundation; either
** version 2.1 of the License, or (at your option) any later version.
**
** This library is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
** Lesser General Public License for more details.
**
** You should have received a copy of the GNU Lesser General Public
** License along with this library; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
 
#include "config.h"
 
#include <cassert>
#include <cerrno>
#include <cstdint>
#include <sstream>
#include <string>
#include <tuple>
 
#include <csignal>
 
namespace jmmcg { namespace LIBJMMCG_VER_NAMESPACE {
 
   /// A nice enum for the exit codes from main().
   /**
      There is some conflicting advice regarding user-defined exit coeds and permissible values:
      -# <a href="https://www.tldp.org/LDP/abs/html/exitcodes.html"/> - between 64-113.
      -# Also see <a href="https://www.freebsd.org/cgi/man.cgi?query=sysexits&apropos=0&sektion=0&manpath=FreeBSD+4.3-RELEASE&format=html">sysexits.h</a> implies values over 128 should be used.
      
      Note use of POSIX compatibility macros & starting our custom errors at 129. Also note that we shouldn't exceed 255, as the exit code is truncated to 8 bits, which would cause problems...
   */
   class exit_codes {
   public:
      enum codes : std::uint8_t {
         exit_success=EXIT_SUCCESS,
         exit_unknown_failure=EXIT_FAILURE,
         exit_unknown_exception=128+_NSIG,   ///< User-defined codes start from here according to "signum-generic.h".
         exit_stl_exception,
         exit_jmmcg_exception,
         exit_crt_exception,
         exit_parameter_error,
         exit_print_help,
         exit_print_version
      };
 
      static std::string
      to_string(codes e) noexcept(false);
      static std::string
      to_string() noexcept(false);
 
   private:
      static inline constexpr std::tuple const descriptions{
         std::tuple{exit_success, "exit_success", "The process completed successfully."},
         std::tuple{exit_unknown_failure, "exit_unknown_failure", "Error: an unknown failure-condition caused the process to exit."},
         std::tuple{exit_unknown_exception, "exit_unknown_exception", "Error: an unknown exception was thrown that caused the process to exit."},
         std::tuple{exit_stl_exception, "exit_stl_exception", "Error: an STL-derived exception was thrown that caused the process to exit."},
         std::tuple{exit_jmmcg_exception, "exit_jmmcg_exception", "Error: a libjmmcg-derived exception was thrown that caused the process to exit."},
         std::tuple{exit_crt_exception, "exit_crt_exception", "Error: a libjmmcg-derived CRT-exception was thrown that caused the process to exit."},
         std::tuple{exit_parameter_error, "exit_parameter_error", "Error: an incorrect set of command-line options caused the process to exit."},
         std::tuple{exit_print_help, "exit_print_help", "The '--help' command-line option caused the process to exit."},
         std::tuple{exit_print_version, "exit_print_version", "The '--version' command-line option caused the process to exit."}
      };
   };
 
} }
 
#include "exit_codes_impl.hpp"
 
#endif