Re: [boost] [system] - creation of system_error

From: Peter Dimov (pdimov_at_[hidden])
Date: 2006-06-27 10:05:37

Christopher Kohlhoff wrote:
> Peter Dimov <pdimov_at_[hidden]> wrote:

>> An operator== that compares both sysno_vaue() and
>> errno_value() would allow the above to work reliably,
>> though... as long as there is a single sysno in the OS, as you
>> pointed out. :-)
> 
> Yes, this does makes me think that it might be better if an
> error_code only had one true value, and that value is
> represented by whatever category and error number it is created
> with. It would only compare as equal to another error_code that
> was created with exactly the same category and error number.
> Conversion between errors in different categories should then be
> explicit (using to_errno or to_sysno, say).

It does have the disadvantage that you would be able to have

e1.sysno == e2.sysno && e1.errno == e2.errno && e1 != e2

though. :-)