098e8b7357
Document the conditional existence of `alloc::sync` and `alloc::task`. `alloc` declares ```rust #[cfg(target_has_atomic = "ptr")] pub mod sync; ``` but there is no public documentation of this condition. This PR fixes that, so that users of `alloc` can understand how to make their code compile everywhere `alloc` does, if they are writing a library with impls for `Arc`. The wording is copied from `std::sync::atomic::AtomicPtr`, with additional advice on how to `#[cfg]` for it. I feel quite uncertain about whether the paragraph I added to `Arc`'s documentation should actually be there, as it is a distraction for anyone using `std`. On the other hand, maybe more reminders that no_std exists would benefit the ecosystem. Note: `target_has_atomic` is [stabilized](https://github.com/rust-lang/rust/issues/32976) but [not yet documented in the reference](https://github.com/rust-lang/reference/pull/1171). |
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| benches | ||
| src | ||
| tests | ||
| Cargo.toml | ||