[boost] [functional/hash] Interface-breaking changes to hash_combine

Subject: [boost] [functional/hash] Interface-breaking changes to hash_combine
From: Joaquin M Lopez Munoz (joaquin_at_[hidden])
Date: 2014-07-27 12:07:56

Hi,

There's been a number of internal changes to the implementation of
boost::hash_combine during this year, with the result that the
documented procedure:

http://www.boost.org/doc/html/hash/reference.html#boost.hash_combine

namely, seed ^= hash_value(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2),
is no longer followed in all cases.

This is a backwards compatibility breach --at the very least I think it
should be documented.

Best,

Joaquín M López Muñoz
Telefónica