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: Matt Calabrese (rivorus_at_[hidden])
Date: 2013-10-02 15:14:05

On Wed, Oct 2, 2013 at 6:07 AM, Thorsten Ottosen <
thorsten.ottosen_at_[hidden]> wrote:

> It's not only a precondition we are dealing with. It's the postcondition
> of the constructor, that is, the invariant of the class. The normal
> response to failing to satisfy the postcondition is to throw.

This is very often the case when violating any precondition. The answer is
that if you don't violate the precondition, then your variants are not
violated. What you describe regarding exceptions actually changes your
function's preconditions. In other words, the assert version's precondition
is that you do not pass a null pointer. The throw version's precondition
does not include that constraint at all -- instead, you've made passing a
null pointer acceptable, with the behavior being that an exception is
thrown in the case that such a pointer is passed.

-- 
-Matt Calabrese