text: /* C interface for result
  (C) 2017-2020 Niall Douglas <http://www.nedproductions.biz/> (6 commits)
  File Created: Aug 2017
  
  
  Boost Software License - Version 1.0 - August 17th, 2003
  
  Permission is hereby granted, free of charge, to any person or organization
  obtaining a copy of the software and accompanying documentation covered by
  this license (the "Software") to use, reproduce, display, distribute,
  execute, and transmit the Software, and to prepare derivative works of the
  Software, and to permit third-parties to whom the Software is furnished to
  do so, all subject to the following:
  
  The copyright notices in the Software and this entire statement, including
  the above license grant, this restriction and the following disclaimer,
  must be included in all copies of the Software, in whole or in part, and
  all derivative works of the Software, unless such copies or derivative
  works are solely in the form of machine-executable object code generated by
  a source language processor.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
  SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
  FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
  ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  DEALINGS IN THE SOFTWARE.
  */
  
  #ifndef BOOST_OUTCOME_EXPERIMENTAL_RESULT_H
  #define BOOST_OUTCOME_EXPERIMENTAL_RESULT_H
  
  #include <stdint.h>  // for intptr_t
  
  #define BOOST_OUTCOME_C_DECLARE_RESULT(ident, R, S)                                                                                                                                                                                                                                                                                        \
    struct cxx_result_##ident                                                                                                                                                                                                                                                                                                    \
    {                                                                                                                                                                                                                                                                                                                            \
      R value;                                                                                                                                                                                                                                                                                                                   \
      unsigned flags;                                                                                                                                                                                                                                                                                                            \
      S error;                                                                                                                                                                                                                                                                                                                   \
    }
  
  #define BOOST_OUTCOME_C_RESULT(ident) struct cxx_result_##ident
  
  
  #define BOOST_OUTCOME_C_RESULT_HAS_VALUE(r) (((r).flags & 1U) == 1U)
  
  #define BOOST_OUTCOME_C_RESULT_HAS_ERROR(r) (((r).flags & 2U) == 2U)
  
  #define BOOST_OUTCOME_C_RESULT_ERROR_IS_ERRNO(r) (((r).flags & (1U << 4U)) == (1U << 4U))
  
  
  /***************************** <system_error2> support ******************************/
  
  #define BOOST_OUTCOME_C_DECLARE_STATUS_CODE(ident, value_type)                                                                                                                                                                                                                                                                             \
    struct cxx_status_code_##ident                                                                                                                                                                                                                                                                                               \
    {                                                                                                                                                                                                                                                                                                                            \
      void *domain;                                                                                                                                                                                                                                                                                                              \
      value_type value;                                                                                                                                                                                                                                                                                                          \
    };
  
  #define BOOST_OUTCOME_C_STATUS_CODE(ident) struct cxx_status_code_##ident
  
  
  struct cxx_status_code_posix
  {
    void *domain;
    int value;
  };
  #define BOOST_OUTCOME_C_DECLARE_RESULT_ERRNO(ident, R) BOOST_OUTCOME_C_DECLARE_RESULT(posix_##ident, R, struct cxx_status_code_posix)
  #define BOOST_OUTCOME_C_RESULT_ERRNO(ident) BOOST_OUTCOME_C_RESULT(posix_##ident)
  
  struct cxx_status_code_system
  {
    void *domain;
    intptr_t value;
  };
  #define BOOST_OUTCOME_C_DECLARE_RESULT_SYSTEM(ident, R) BOOST_OUTCOME_C_DECLARE_RESULT(system_##ident, R, struct cxx_status_code_system)
  #define BOOST_OUTCOME_C_RESULT_SYSTEM(ident) BOOST_OUTCOME_C_RESULT(system_##ident)
  
  #endif
  