Re: [boost] [system] remarks and feedback

From: Beman Dawes (bdawes_at_[hidden])
Date: 2006-07-04 10:06:03

"Christopher Kohlhoff" <chris_at_[hidden]> wrote in message 
news:20060628140024.38036.qmail_at_web32601.mail.mud.yahoo.com...
> I'm thinking it might be helpful in the discussion for me to try
> to document in precise terms what asio would need from
> error_code and how it would be used.
>
> What's needed from error_code
> =============================
>
> Testing for equality:
>
>  Given
>    error_code ec1(value1, category1);
>    error_code ec2(value1, category1);
>    error_code ec3(value2, category1);
>  Then
>    ec1 == ec2 evaluates to true
>    ec1 == ec3 evaluates to false

Makes sense.

>
> What asio will say
> ==================
>
> (For the sake of brevity I will only discuss a couple of error
> codes, but others will follow the same pattern.)
>
> There will be an error_code object:
>
>  namespace boost { namespace asio { namespace error {
>    extern error_code connection_reset;
>  }}}

Yes, but shouldn't that be: extern const error_code connection_reset;

You don't want users to be able to change connection_reset to some other 
value.

> On non-POSIX implementations, the initialisation of
> connection_reset is implementation-defined.
>
> On POSIX implementations, the initialisation of connection_reset
> shall be:
>
>  error_code connection_reset(ECONNRESET, from_errno);
>
> such that both of the following expressions shall evaluate to
> true:
>
>  connection_reset == error_code(ECONNRESET, from_errno)
>  connection_reset.errno_value() == ECONNRESET

Yes.

> ... More examples

I think we are on track. I'll try to post a revised interface later today.
>
> That's all I can think of for now.

Thanks for the examples. That really helps.

--Beman