Re: [Boost-users] Library Interface Design

From: David Abrahams (dave_at_[hidden])
Date: 2006-09-13 10:29:21

Edward Diener <eldiener_at_[hidden]> writes:

> Johan Nilsson wrote:
>
>>> and seem to
>>> contradict the advice of the designers of the .NET API.
>> 
>> Different platform and philosophy, unless you're talking about C++/CLI.
>> 
>
> C++/CLI is not an exception. C++/CLI follows the .Net philosophy and 
> rules regarding the construction of objects, not the C++ philosophy and 
> rules, as I pointed out in another post on this thread. Because of that 
> it is not necessarily apropos to use .Net as a basis for discussion of 
> constructor philosophy in C++, although .Net's reliance on properties 
> and events does have an anology to work that has been done with C++ 
> lately, and does affect how one thinks about constructing and using objects.

C++/CLI's default null-initialization of references doesn't in any way
justify designs that pass out half-baked objects to users, any more
than we would approve of passing out half-baked objects containing
only shared_ptr<>s in C++.  It's bad design.  It makes the client of a
class responsible for things that the class designer should have taken
care of.  That's a universal no-no, regardless of what language the
code is written in.

Default null-initialization of references does make it easier to not
think about certain exception-safety and object state issues and "get
away with it" some of the time, but that doesn't make code written
that way correct.  Usually, it just means that bugs may be masked or
harder to detect.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com