--- /dev/null
+#ifndef BOOST_SYSTEM_DETAIL_GENERIC_CATEGORY_MESSAGE_HPP_INCLUDED
+#define BOOST_SYSTEM_DETAIL_GENERIC_CATEGORY_MESSAGE_HPP_INCLUDED
+
+// Implementation of generic_error_category_message
+//
+// Copyright 2018 Peter Dimov
+//
+// 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)
+//
+// See library home page at http://www.boost.org/libs/system
+
+#include <boost/config.hpp>
+#include <string>
+#include <cstring>
+
+namespace boost
+{
+
+namespace system
+{
+
+namespace detail
+{
+
+#if defined(__GLIBC__)
+
+// glibc has two incompatible strerror_r definitions
+
+inline char const * strerror_r_helper( char const * r, char const * ) BOOST_NOEXCEPT
+{
+ return r;
+}
+
+inline char const * strerror_r_helper( int r, char const * buffer ) BOOST_NOEXCEPT
+{
+ return r == 0? buffer: "Unknown error";
+}
+
+inline char const * generic_error_category_message( int ev, char * buffer, std::size_t len ) BOOST_NOEXCEPT
+{
+ return strerror_r_helper( strerror_r( ev, buffer, len ), buffer );
+}
+
+inline std::string generic_error_category_message( int ev )
+{
+ char buffer[ 128 ];
+ return generic_error_category_message( ev, buffer, sizeof( buffer ) );
+}
+
+#else // #if defined(__GLIBC__)
+
+// std::strerror is thread-safe on everything else, incl. Windows
+
+# if defined( BOOST_MSVC )
+# pragma warning( push )
+# pragma warning( disable: 4996 )
+# elif defined(__clang__) && defined(__has_warning)
+# pragma clang diagnostic push
+# if __has_warning("-Wdeprecated-declarations")
+# pragma clang diagnostic ignored "-Wdeprecated-declarations"
+# endif
+# endif
+
+inline std::string generic_error_category_message( int ev )
+{
+ char const * m = std::strerror( ev );
+ return m? m: "Unknown error";
+}
+
+inline char const * generic_error_category_message( int ev, char * buffer, std::size_t len ) BOOST_NOEXCEPT
+{
+ if( len == 0 )
+ {
+ return buffer;
+ }
+
+ if( len == 1 )
+ {
+ buffer[0] = 0;
+ return buffer;
+ }
+
+ char const * m = std::strerror( ev );
+
+ if( m == 0 ) return "Unknown error";
+
+ std::strncpy( buffer, m, len - 1 );
+ buffer[ len-1 ] = 0;
+
+ return buffer;
+}
+
+# if defined( BOOST_MSVC )
+# pragma warning( pop )
+# elif defined(__clang__) && defined(__has_warning)
+# pragma clang diagnostic pop
+# endif
+
+#endif // #if defined(__GLIBC__)
+
+} // namespace detail
+
+} // namespace system
+
+} // namespace boost
+
+#endif // #ifndef BOOST_SYSTEM_DETAIL_GENERIC_CATEGORY_MESSAGE_HPP_INCLUDED