Created on 2016-12-16.00:00:00 last changed 87 months ago
Proposed resolution:
This wording is relative to N4604.
Edit [numeric.ops.gcd] as indicated:
template<class M, class N> constexpr common_type_t<M, N> gcd(M m, N n);-2- Requires:
|m| shall be representable as a value of type M and |n| shall be representable as a value of type N|m| and |n| shall be representable as a value of common_type_t<M, N>. [Note: These requirements ensure, for example, that gcd(m, m) = |m| is representable as a value of type M. — end note]
Edit [numeric.ops.lcm] as indicated:
template<class M, class N> constexpr common_type_t<M, N> lcm(M m, N n);-2- Requires:
|m| shall be representable as a value of type M and |n| shall be representable as a value of type N|m| and |n| shall be representable as a value of common_type_t<M, N>. The least common multiple of |m| and |n| shall be representable as a value of type common_type_t<M, N>.
[ 2017-01-27 Telecon ]
Priority 0
This is a duplicate of 2792, which addressed LFTS 2.
By the current definition, gcd((int64_t)1234, (int32_t)-2147483648) is ill-formed (because 2147483648 is not representable as a value of int32_t.) We want to change this case to be well-formed. As long as both |m| and |n| are representable as values of the common type, absolute values can be calculate d without causing unspecified behavior, by converting m and n to the common type before taking the negation.
Suggested resolution:
|m| shall be representable as a value of type M and |n| shall be representable as a value of type N|m| and |n| shall be representable as a value of common_type_t<M, N>.
History | |||
---|---|---|---|
Date | User | Action | Args |
2017-07-30 20:15:43 | admin | set | status: wp -> c++17 |
2017-03-05 23:41:16 | admin | set | status: ready -> wp |
2017-01-30 15:17:53 | admin | set | messages: + msg8812 |
2017-01-30 15:17:53 | admin | set | status: new -> ready |
2016-12-16 21:24:37 | admin | set | messages: + msg8757 |
2016-12-16 00:00:00 | admin | create |