Discuss the `WrapperStruct(UnsafeCell<some_c_struct>)`FFI pattern
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Description
Hey everyone,
I’d like to suggest adding the interior mutability FFI wrapper pattern to the FFI section, which usually looks something like this
#[repr(transparent)]
WrapperStruct(UnsafeCell<some_c_struct>)
This is used in e.g. the Linux kernel safe wrapper
I didn’t really understand it at first, but somebody explained it extremely well on Discord. Some of the explanation could likely be copied and pasted https://discord.com/channels/273534239310479360/818964227783262209/1040580112330002443
In general, I think the FFI section could use some updating, to be less of “this is how you call C functions” to more of “this is how you wrap a C API and make it safe”, since that’s what a lot of people are doing now as Rust works in to existing C projects. But that’s a big change, suitable for a separate issue.
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Research direction
Start in the Nomicon's FFI section and review the linked Discord explanation for the WrapperStruct(UnsafeCell<some_c_struct>) pattern. Add a clear explanation of how this wrapper supports safe C API abstractions, while treating the broader FFI section rewrite as separate work.
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Assessment
- Tech stack
- rust
- Domain
- documentation
- Issue type
- Documentation
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100