Tracking issue for RFC 2521, "Unify std::os::raw::c_void and libc::c_void via libcore"

[Centril]

This is a tracking issue for the RFC "Unify std::os::raw::c_void and libc::c_void via libcore" (rust-lang/rfcs#2521).

Steps:

• Implement the RFC: Move std::os::raw::c_void into libcore and re-export in libstd #53910, Re-export core::ffi::c_void if it exists libc#1082
• Adjust documentation (see instructions on forge)
• Stabilization PR (see instructions on forge)

Unresolved questions:

There are none.

[Ericson2314]

OK per what @retep998 was saying, if we can get Cargo to ensure that use_std is always used when std is used, we can and should avoid putting anything in libcore.

[alexcrichton]

@Ericson2314 without a design of how to do that it's simply not an option. There is no ability to do that today, and it's not clear how that would be done (nor whether it's desirable).

[IsaacWoods]

I'd like to work on this :)

[IsaacWoods]

Afaik the implementation for this is now complete and will be insta-stable from 1.31.0

[SimonSapin]

Thanks for your PRs @IsaacWoods!

I believe core::ffi::c_void is also available in 1.30.0. What do you think of having libc’s build script do feature detection (run rustc on a dummy file that imports core::ffi::c_void) instead of version detection like rust-lang/libc#1082 does?

[IsaacWoods]

I went with 1.31.0 to make sure not to break nightly users using a 1.30.0 libstd without the change but upgrading libc, but feature detection would probably be better. I’ll send another PR when I have the chance