Re: [boost] [container] moving a pre-built vector into a flat_set

Subject: Re: [boost] [container] moving a pre-built vector into a flat_set
From: Thorsten Ottosen (tottosen_at_[hidden])
Date: 2015-09-17 04:00:18

On 16-09-2015 19:40, Francois Duranleau wrote:

> The is_sorted check would be in an assert, so it would go away in release
> builds (this is just validation of precondition, much like we would assert in
> std::vector<T>::operator[] for out-of-range indices).

Yes, of course in an assertion.

> Granted, this check is
> costly, and ideally we would like to have control on how expensive we allow
> validation of preconditions to be. Personally, I wouldn't mind if the check is
> not done at all. I was merely suggesting in which case we might add this
> check.

Well, you already paid at least O(n) time to build the container that 
you are moving from. You won't get a different complexity because of 
this check. On the other hand, you might catch a lot of accidental 
problems (say, not being sorted or being sorted with the wrong predicate).

These operations allow the user to break the invariant of the container, 
an assertion would be the minimum to expect as a guard against this.

kind regards

Thorsten