Messages in this thread | | | From | "Andreas Hindborg (Samsung)" <> | Subject | Re: [PATCH v3 1/9] rust: add offset_of! macro | Date | Mon, 21 Aug 2023 20:43:08 +0200 |
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Hi Alice,
Alice Ryhl <aliceryhl@google.com> writes:
> From: Wedson Almeida Filho <walmeida@microsoft.com> > > This macro is used to compute the offset of a field in a struct. > > This commit enables an unstable feature that is necessary for using > the macro in a constant. However, this is not a problem as the macro > will become available from the Rust standard library soon [1]. The > unstable feature can be disabled again once that happens. > > The macro in this patch does not support sub-fields. That is, you cannot > write `offset_of!(MyStruct, field.sub_field)` to get the offset of > `sub_field` with `field`'s type being a struct with a field called > `sub_field`. This is because `field` might be a `Box<SubStruct>`, which > means that you would be trying to compute the offset to something in an > entirely different allocation. There's no easy way to fix the current > macro to support subfields, but the version being added to the standard > library should support it, so the limitation is temporary and not a big > deal.
I think `#![feature(offset_of)]` is available in 1.71.0, can we use that directly?
BR Andreas
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