id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
12171,boost::multiprecision should provide a hash function,Tassilo Glander <tassilo.glander@…>,John Maddock,"For boost::multiprecision types to be used in std::unordered_map etc., they need to provide a hash function. A straightforward way on cpp_int would be to use the internal limbs like:

size_t getHashCode() const
{
    std::size_t result = _number.sign();
    std::size_t size = _number.backend().size();
    auto p = _number.backend().limbs();

    for (std::size_t i = 0; i < size; ++i) {
        boost::hash_combine(result, *p);
        ++p;
    }
    return result;
}
and the accompanying hash functor.
",Feature Requests,closed,To Be Determined,multiprecision,Boost 1.60.0,Optimization,fixed,,