c++ - Charset used by boost-asio error message -

i using boost-asio , want process correctly error message.

in example, made typo (1278 instead of 127):

boost::system::error_code ec; auto address=boost::asio::ip::address::from_string("1278.0.0.1",ec); if(ec) {     const char*text=ec.message().c_str();     //do text encoding ? } 

i error message , seems encoded in windows 1252 (i using windows 7). seems encoding os encoding.

however, unable find documentation states fact.

are error message in boost asio encoded os character set ?

after digging boost on system, found included hpp files include ipp file in turn calls os functions. if there error, code of error known @ stage.

the real error message formed when message() function called.

the implementation on windows calls formatmessagea or formatmessagew depending if boost_no_ansi_apis defined:

  std::string system_error_category::message( int ev ) const   { # ifndef boost_no_ansi_apis       lpvoid lpmsgbuf = 0;     dword retval = ::formatmessagea(          format_message_allocate_buffer |          format_message_from_system |          format_message_ignore_inserts,         null,         ev,         makelangid(lang_neutral, sublang_default), // default language         (lpstr) &lpmsgbuf,         0,         null      );     detail::local_free_on_destruction lfod(lpmsgbuf);     if (retval == 0)         return std::string("unknown error");      std::string str( static_cast<lpcstr>(lpmsgbuf) ); # else  // wince workaround     lpvoid lpmsgbuf = 0;     dword retval = ::formatmessagew(          format_message_allocate_buffer |          format_message_from_system |          format_message_ignore_inserts,         null,         ev,         makelangid(lang_neutral, sublang_default), // default language         (lpwstr) &lpmsgbuf,         0,         null      );     detail::local_free_on_destruction lfod(lpmsgbuf);     if (retval == 0)         return std::string("unknown error");      int num_chars = (wcslen( static_cast<lpcwstr>(lpmsgbuf) ) + 1) * 2;     lpstr narrow_buffer = (lpstr)_alloca( num_chars );     if (::widechartomultibyte(cp_acp, 0, static_cast<lpcwstr>(lpmsgbuf), -1, narrow_buffer, num_chars, null, null) == 0)         return std::string("unknown error");      std::string str( narrow_buffer ); # endif     while ( str.size()       && (str[str.size()-1] == '\n' || str[str.size()-1] == '\r') )         str.erase( str.size()-1 );     if ( str.size() && str[str.size()-1] == '.' )        { str.erase( str.size()-1 ); }     return str;   } 

if message calls formatmessagew, string narrowed system default windows ansi code page (cp_acp)

in cases on windows result default ansi codepage.