Date: Wed, 14 Jan 2026 14:03:31 -0800
On Wednesday, 14 January 2026 13:50:31 Pacific Standard Time Jonathan Wakely
via Std-Proposals wrote:
> > Note that it is generally impossible to make the modifying operation and
> > the notifying operation atomic with the currently available futex-like
> > system APIs.
>
> FUTEX_WAKE_OP supports it, but I don't think the futex-like operations on
> other operating systems (like _umtx_op on FreeBSD) have an equivalent.
And of course, futex only works on int-sized objects. It couldn't be used for
std::atomic<std::uintptr_t> for example.
via Std-Proposals wrote:
> > Note that it is generally impossible to make the modifying operation and
> > the notifying operation atomic with the currently available futex-like
> > system APIs.
>
> FUTEX_WAKE_OP supports it, but I don't think the futex-like operations on
> other operating systems (like _umtx_op on FreeBSD) have an equivalent.
And of course, futex only works on int-sized objects. It couldn't be used for
std::atomic<std::uintptr_t> for example.
-- Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Principal Engineer - Intel Data Center - Platform & Sys. Eng.
Received on 2026-01-14 22:03:33