Tracking Issue for `std::ffi::c_str` module

[clarfonthey]

Feature gate: #![feature(c_str_module)]

This is a tracking issue for the std::ffi::c_str module.

Public API

This adds {core, alloc, std}::ffi::c_str modules and migrates some existing types into them. Types will still be re-exported in their current places to ensure compatibility.

The following migrations are made:

• core::ffi::CStr => core::ffi::c_str::CStr
• core::ffi::FromBytesUntilNulError => core::ffi::c_str::FromBytesUntilNulError
• core::ffi::FromBytesWithNulError => core::ffi::c_str::FromBytesWithNulError
• alloc::ffi::CString => alloc::ffi::c_str::CString
• alloc::ffi::FromVecWIthNulError => alloc::ffi::c_str::FromVecWIthNulError
• alloc::ffi::IntoStringError => alloc::ffi::c_str::IntoStringError
• alloc::ffi::NulError => alloc::ffi::c_str::NulError

And these types are also migrated on the std crate as well.

Steps / History

• API change proposal (ACP)¹: ACP: std::ffi::c and std::ffi::os submodules libs-team#134
• Implementation: Add std::ffi::c_str module #112136
• Final comment period (FCP)²
• Stabilization PR

Unresolved Questions

• Should c_str and c_string be separated? This was not discussed in the original ACP. Decision: no.

Footnotes

1. https://std-dev-guide.rust-lang.org/feature-lifecycle/api-change-proposals.html ↩

2. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩

[dtolnay]

@rust-lang/libs-api:
@rfcbot fcp merge

This module has been available since 1.78-nightly, and is valuable in tidying all those types you will never need to name out of std::ffi's "Structs" section.

Without modules, are you able to guess whether std::ffi::IntoStringError refers to the error type returned by std::ffi::CString::into_string or by std::ffi::OsString::into_string?

Before:

After:

[rfcbot]

Team member @dtolnay has proposed to merge this. The next step is review by the rest of the tagged team members:

• @Amanieu
• @BurntSushi
• @dtolnay
• @joshtriplett
• @m-ou-se

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

[clarfonthey]

Note that the os_str module, while part of the initial ACP, was rejected, and isn't part of this tracking issue. If you'd like to include it as part of the FCP, I would not oppose, but that should be stated explicitly instead of being roped in implicitly. Just don't want to avoid a headache when it comes to stabilisation.

[joshtriplett]

For people wanting to follow std::ffi::os_str, it's #120048 .

[rfcbot]

🔔 This is now entering its final comment period, as per the review above. 🔔