Feature gate: #![feature(atomic_try_update)]

This is a tracking issue for an infallible version of AtomicT::fetch_update as well as a new name for the existing fallible version.

When and if this gets stabilized, the existing fetch_update should be marked as a deprecated alias for try_update.

Public API

impl AtomicT {
    // same as `fetch_update`
    pub fn try_update(
        &self,
        set_order: Ordering,
        fetch_order: Ordering,
        f: impl FnMut(T) -> Option<T>,
    ) -> Result<T, T>;

    pub fn update(
        &self,
        set_order: Ordering,
        fetch_order: Ordering,
        f: impl FnMut(T) -> T,
    ) -> T;
}

Steps / History

• ACP: Infallible version of fetch_update libs-team#490
• Design requested by t-libs-api in Implement AtomicT::update & AtomicT::try_update #133829 (comment)
• Implementation: Implement AtomicT::update & AtomicT::try_update #133829
• Final comment period (FCP)¹
• Stabilization PR: Stabilize atomic_try_updateand deprecate fetch_update starting 1.99.0 #148590

Unresolved Questions

• Implement AtomicT::update & AtomicT::try_update #133829 (comment)