rust-lang / rust-lang/rust-bindgen

How to avoid bindgen being out of sync with cc?

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Rust
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Description

My understanding is, that it is very common to wrap a C library in a Rust *-sys crate by using bindgen to automatically generate Rust bindings and cc to compile the C code.

As far as I understand it bindgen uses libclang to parse the C headers and cc uses whatever compiler the user provides.

This can lead to problems, because both toolchains don't need to agree on everything. While cross compiling for thumbv6m-none-eabi on Windows, bindgen generated u32 for enums and cc used u8 when possible (-fshort-enums).

This is quite unfortunate and hard to catch. Is there a common workaround for this?

PS: If there is a better place for this issue please tell me.

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Research direction

Review how bindgen uses libclang and how cc invokes the selected compiler during thumbv6m-none-eabi cross-compilation on Windows, focusing on enum widths and -fshort-enums. Done would be a documented, reproducible workaround or a project change that keeps generated Rust representations consistent with the compiled C ABI.

Written by the indexing model from the issue text.

Assessment

Tech stack
c, rust
Domain
compilers, tooling
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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