Issue 3199: istream >> bitset<0> fails

Title: istream >> bitset<0> fails
Status: c++20
Section: [bitset.operators]
Submitter: Davis Herring

Created on 2019-04-05.00:00:00 last changed 46 months ago

Messages

msg10389 (view)

Date: 2019-04-06.16:35:32

Proposed resolution:

This wording is relative to N4810.

Modify [bitset.operators] as indicated:
```
template<class charT, class traits, size_t N>
  basic_istream<charT, traits>&
    operator>>(basic_istream<charT, traits>& is, bitset<N>& x);
```
[…]
-6- If N > 0 and no characters are stored in str, calls is.setstate(ios_base::failbit) (which may throw ios_base::failure ([iostate.flags])).

msg10388 (view)

Date: 2019-06-10.05:20:17

From a StackOverflow question:

[bitset.operators]/5.1 says that extracting a bitset<0> stops after reading 0 characters. /6 then says that, since no characters were stored, failbit is set.

[2019-06-09; Priority to 0 and Status to Tentatively Ready after five positive votes on the reflector.]

History
Date	User	Action	Args
2021-02-25 10:48:01	admin	set	status: wp -> c++20
2019-07-22 15:46:37	admin	set	status: voting -> wp
2019-06-17 05:25:36	admin	set	status: ready -> voting
2019-06-10 05:20:17	admin	set	status: new -> ready
2019-04-06 16:35:32	admin	set	messages: + msg10389
2019-04-05 00:00:00	admin	create