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