P1505 Mandating the Standard Library: Clause 30 - Atomic operations library

[wg21bot]

P1505R0 Mandating the Standard Library: Clause 30 - Atomic operations library (Daniel Sunderland)

[wg21bot]

P1505R1 Mandating the Standard Library: Clause 31 - Atomic operations library (Daniel Sunderland)

[mclow]

Note that P1723 is doing the same thing; we should only deal with one of them. Will resolve which one before Cologne.

[mclow]

After talking with Daniel, we're going to go forward with P1723