Re: [Boost-users] [containers] defining the insertion point of non-unique keys

Subject: Re: [Boost-users] [containers] defining the insertion point of non-unique keys
From: Daniel James (daniel_james_at_[hidden])
Date: 2009-12-18 11:19:59

2009/12/18 Joaquin M Lopez Munoz <joaquin_at_[hidden]>:
>
> No, it's more general than this: assume we've got a container
> with elements
>
>  a1, a2, ... , an, k1, k2, ... , km, b1, b2, ... , bl
>
> where k1, ... , km are equivalent (and the rest are not
> equivalent to these). Put A=[a1,k1), K=[k1,b1), B=[b1,end]. Now
> if we insert an element equivalent to these in K using hint p,
> then:
>
> * if p is in A, insertion takes place before k1,
> * if p is in K, insertion takes place before p,
> * if p is in B, insertion takes place before b1.

Looking at n3000, only associative containers' 'insert' is specified
this way. For 'emplace_hint', it says:

    equivalent to a.emplace(std::forward<Args>(args)...).
    [...]
    Implementations are permitted to ignore the hint.

which I think means that the element is placed at the end of the
equivalent elements. There are similar definitions for unordered
containers' 'insert' with hint and 'emplace_hint'. Presumably this is
a defect?

Daniel