Re: [boost] Looking for thoughts on a new smart pointer: shared_ptr_nonnull

Subject: Re: [boost] Looking for thoughts on a new smart pointer: shared_ptr_nonnull
From: Julian Gonggrijp (j.gonggrijp_at_[hidden])
Date: 2013-10-08 18:12:03

Nevin Liber wrote:

> On 8 October 2013 13:17, Thorsten Ottosen wrote:
> 
>> We just need to find a way to give both camps what they want, since both a
>> valid use-cases.
> 
> No, we don't.  Decide if your API has preconditions or not.  For instance,
> the real difference between vector::operator[] and vector::at() is that the
> former has a precondition while the latter does not.  If you define the
> behavior, it isn't a precondition, precisely because you are explicitly
> allowing it, and a correct program can call it with any value it likes.
> 
> This is, of course, one of the many hard parts of library design.  Make
> strong choices.  Making it "configurable" whether or not something is a
> precondition is a weak choice.
> 
> This, of course, doesn't mean you can't be friendlier if/when you detect a
> precondition violation in debug mode.  But be very clear that it is a
> precondition violation resulting in undefined behavior.

+1