[boost] filesystem::is_directory return true when exception is disabled and this directory does't exist

From: Liao Weijie (i.c.code_at_[hidden])
Date: 2004-10-11 09:01:47

// the snip of code in filesystem::is_directory begin---

      DWORD attributes = ::GetFileAttributesA(
ph.native_directory_string().c_str() );
      if ( attributes == 0xFFFFFFFF )
        boost::throw_exception( filesystem_error(
          "boost::filesystem::is_directory",
          ph, fs::detail::system_error_code() ) );
      return (attributes & FILE_ATTRIBUTE_DIRECTORY) != 0;

//-------------------------------------------------------end--

When GetFileAttributesA failed but the exception is disabled,  the
(attributes & FILE_ATTRIBUTE_DIRECTORY)  will always be true.

Is it a bug?