Re: [boost] [container] locking for compact map

Vicente J. Botet Escriba writes:

Le 09/12/14 09:41, Joaquin M Lopez Munoz a écrit :

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Vicente J. Botet Escriba writes:

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* The move constructor is not noexcept.

An implementation using vector should avoid this last issue.

Or just a pointer to array, which is somewhat more efficient. Why not.

Well, on second thought this is not that easy. Moving from a to b must leave a in a *valid* position, which here means that either you must allocate a new array for a (which makes moving non-noexcept) or assign it a null pointer and deal with the situation in the rest of the interface, which is a kind of a bummer --for instance, as having size()==N is an invariant of the class, even const functions such as cbegin() or cend() need to check for null pointer and allocate accordingly, becoming non-nonexcept, thread unsafe and whatnot. So, I think your deign shouldn't try to be move-aware, much as std::array is not either. Joaquín M López Muñoz Telefónica