Docs for size_of::<#[repr(C)]> items. #44897
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Most of this info comes from camlorn's blog post on optimizing struct layout and the Rustonomicon.
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r? @aturon (rust_highfive has picked a reviewer for you, use r? to override) |
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(Why do I always forget this?) |
src/libcore/mem.rs
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| @@ -209,6 +209,35 @@ pub fn forget<T>(t: T) { | |||
| /// The mutability of a pointer does not change its size. As such, `&T` and `&mut T` | |||
| /// have the same size. Likewise for `*const T` and `*mut T`. | |||
| /// | |||
| /// # Size of #[repr(C)] items | |||
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Put #[repr(C)] inside backticks `…`.
src/libcore/mem.rs
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| /// Enums that carry no data other than the descriminant have the same size as C enums | ||
| /// on the platform they are compiled for. | ||
| /// | ||
| /// ## Unions |
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I don't know what's wrong with linkchecker, but it seems this title is not acceptable.
[01:09:19] std/mem/index.html:32: broken link fragment `#unions` pointing to `std/mem/index.html`
[01:09:25] core/mem/index.html:32: broken link fragment `#unions` pointing to `core/mem/index.html`
[01:09:28] thread 'main' panicked at 'found some broken links', /checkout/src/tools/linkchecker/main.rs:49:8
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@Havvy Ok the problem is that ManuallyDrop is a union, so there's already a "Unions" section in the documentation (check https://doc.rust-lang.org/std/mem/index.html). The linkchecker error message should say something like "duplicated link ID".
Could we workaround by saying "Size of Structs"/"Size of Enums"/"Size of Unions"?
alexcrichton
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@bors: r+ rollup thanks! ❤️ |
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📌 Commit 0ece48e has been approved by |
Docs for size_of::<#[repr(C)]> items. Most of this info comes from camlorn's blog post on optimizing struct layout and the Rustonomicon. I don't really like my wording in the first paragraph. I also cannot find a definition of what `#[repr(C)]` does for enums that have variants with fields. They're allowed, unlike `#[repr(C)] enum`s with no variants.
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☀️ Test successful - status-appveyor, status-travis |
Most of this info comes from camlorn's blog post on optimizing struct layout and the Rustonomicon.
I don't really like my wording in the first paragraph.
I also cannot find a definition of what
#[repr(C)]does for enums that have variants with fields. They're allowed, unlike#[repr(C)] enums with no variants.