Boost logo

Boost :

Subject: Re: [boost] [container][set, map, flat_set, flat_map, +multi_xxx] operator< and operator== seems to ignore custom KeyCompare
From: Evgeny Panasyuk (evgeny.panasyuk_at_[hidden])
Date: 2013-07-17 19:07:42

18.07.2013 1:22, Ion Gaztañaga:
> (taken from N3680) Table 98 — Optional container operations
> -> Operational semantics lexicographical_compare
> (a.begin(), a.end(), b.begin(), b.end())
> -> Assertion/note: pre: < is defined for values of T. < is a total
> ordering relationship.
> I guess using Compare for associative containers' operator < could
> perfectly work it won't be the standard behaviour.

+ also, here (Table 98) < is **total ordering**, while "23.2.4
Associative containers" says:
2. Each associative container is parameterized on Key and an ordering
relation Compare that induces a **strict weak ordering** (25.4) on
elements of Key. In addition, map and multimap associate an arbitrary
mapped type T with the Key. The object of type Compare is called the
comparison object of a container.

Evgeny Panasyuk

Boost list run by bdawes at, gregod at, cpdaniel at, john at