//  Boost system_error.hpp  --------------------------------------------------//

//  Copyright Beman Dawes 2006

//  Distributed under the Boost Software License, Version 1.0. (See accompanying

//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_SYSTEM_ERROR_HPP

#define BOOST_SYSTEM_ERROR_HPP

#include <string>

#include <stdexcept>

#include <cassert>

#include <boost/system/error_code.hpp>

namespace boost

{

  namespace system

  {

    //  class system_error  --------------------------------------------------//

    class system_error : public std::runtime_error

    {

    public:

      system_error( error_code ec )

          : std::runtime_error(""), m_error_code(ec) {}

      system_error( error_code ec, const std::string & what_arg )

          : std::runtime_error(what_arg), m_error_code(ec) {}

      system_error( error_code ec, const char* what_arg )

          : std::runtime_error(what_arg), m_error_code(ec) {}

      system_error( int ev, const error_category & ecat )

          : std::runtime_error(""), m_error_code(ev,ecat) {}

      system_error( int ev, const error_category & ecat,

        const std::string & what_arg )

          : std::runtime_error(what_arg), m_error_code(ev,ecat) {}

      system_error( int ev, const error_category & ecat,

        const char * what_arg )

          : std::runtime_error(what_arg), m_error_code(ev,ecat) {}

      virtual ~system_error() throw() {}

      const error_code &  code() const throw() { return m_error_code; }

      const char *        what() const throw();

    private:

      error_code           m_error_code;

      mutable std::string  m_what;

    };

    //  implementation  ------------------------------------------------------//

    inline const char * system_error::what() const throw()

    // see http://www.boost.org/more/error_handling.html for lazy build rationale

    {

      if ( m_what.empty() )

      {

        try

        {

          m_what = this->std::runtime_error::what();

          if ( m_error_code )

          {

            if ( !m_what.empty() ) m_what += ": ";

            m_what += m_error_code.message();

          }

        }

        catch (...) { return std::runtime_error::what(); }

      }

      return m_what.c_str();

    }

  } // namespace system

} // namespace boost

#endif // BOOST_SYSTEM_ERROR_HPP