boost/system/system_error.hpp

   1 //  Boost system_error.hpp  --------------------------------------------------//
   2
   3 //  Copyright Beman Dawes 2006
   4
   5 //  Distributed under the Boost Software License, Version 1.0. (See accompanying
   6 //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7
   8 #ifndef BOOST_SYSTEM_ERROR_HPP
   9 #define BOOST_SYSTEM_ERROR_HPP
  10
  11 #include <string>
  12 #include <stdexcept>
  13 #include <cassert>
  14 #include <boost/system/error_code.hpp>
  15
  16 namespace boost
  17 {
  18   namespace system
  19   {
  20     //  class system_error  --------------------------------------------------//
  21
  22     class system_error : public std::runtime_error
  23     {
  24     public:
  25       system_error( error_code ec )
  26           : std::runtime_error(""), m_error_code(ec) {}
  27
  28       system_error( error_code ec, const std::string & what_arg )
  29           : std::runtime_error(what_arg), m_error_code(ec) {}
  30
  31       system_error( error_code ec, const char* what_arg )
  32           : std::runtime_error(what_arg), m_error_code(ec) {}
  33
  34       system_error( int ev, const error_category & ecat )
  35           : std::runtime_error(""), m_error_code(ev,ecat) {}
  36
  37       system_error( int ev, const error_category & ecat,
  38         const std::string & what_arg )
  39           : std::runtime_error(what_arg), m_error_code(ev,ecat) {}
  40
  41       system_error( int ev, const error_category & ecat,
  42         const char * what_arg )
  43           : std::runtime_error(what_arg), m_error_code(ev,ecat) {}
  44
  45       virtual ~system_error() throw() {}
  46
  47       const error_code &  code() const throw() { return m_error_code; }
  48       const char *        what() const throw();
  49
  50     private:
  51       error_code           m_error_code;
  52       mutable std::string  m_what;
  53     };
  54
  55     //  implementation  ------------------------------------------------------//
  56
  57     inline const char * system_error::what() const throw()
  58     // see http://www.boost.org/more/error_handling.html for lazy build rationale
  59     {
  60       if ( m_what.empty() )
  61       {
  62         try
  63         {
  64           m_what = this->std::runtime_error::what();
  65           if ( m_error_code )
  66           {
  67             if ( !m_what.empty() ) m_what += ": ";
  68             m_what += m_error_code.message();
  69           }
  70         }
  71         catch (...) { return std::runtime_error::what(); }
  72       }
  73       return m_what.c_str();
  74     }
  75
  76   } // namespace system
  77 } // namespace boost
  78
  79 #endif // BOOST_SYSTEM_ERROR_HPP
  80
  81