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Tracking Issue for const_cstr_from_ptr #113219
Description
Feature gate: #![feature(const_cstr_from_ptr)]
This is a tracking issue for using CStr::from_ptr() in a const context.
This method was previously gated under const_cstr_methods, but was split off after discussion in #107624 (review).
Public API
// core/ffi/c_str.rs
impl CStr {
pub const unsafe fn from_ptr<'a>(ptr: *const c_char) -> &'a CStr;
pub const fn count_bytes(&self) -> usize;
}Steps / History
- Implementation
-
Blocked on Relax const-eval restrictions rfcs#3352 (?)- Not blocked after all
- Final comment period (FCP)[^1]
- Stabilization PR: Stabilize const_cstr_from_ptr (CStr::from_ptr, CStr::count_bytes) #127433
Unresolved Questions
Making this const currently depends on const_eval_select, which unstable. If const_eval_select becomes internally usable, we will be able to stabilize this.
The other currently available option is to always use a const strlen, but this would come with a performance hit.
Alternatively, whenever CStr becomes a thin pointer this can be const stabilized since it will have no internal operations.
Activity
Update the tracking issue for `const_cstr_from_ptr`
Rollup merge of rust-lang#113252 - tgross35:const-cstr-from-ptr-track…
Rollup merge of rust-lang#113252 - tgross35:const-cstr-from-ptr-track…
Rollup merge of rust-lang#113252 - tgross35:const-cstr-from-ptr-track…
tgross35 commentedon Aug 3, 2023
I gated
CStr::count_bytes()'s constness under this same flag since it depends on the same decision. See #11444328 remaining items
rfcbot commentedon Jul 6, 2024
The final comment period, with a disposition to merge, as per the review above, is now complete.
As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.
This will be merged soon.
Rollup merge of rust-lang#127433 - dtolnay:conststrlen, r=workingjubilee
Rollup merge of rust-lang#127433 - dtolnay:conststrlen, r=workingjubilee
Rollup merge of rust-lang#127433 - dtolnay:conststrlen, r=workingjubilee
Rollup merge of rust-lang#127433 - dtolnay:conststrlen, r=workingjubilee
Rollup merge of rust-lang#127433 - dtolnay:conststrlen, r=workingjubilee
Unrolled build for rust-lang#127433
Rename the internal `const_strlen` to just `strlen`
Rollup merge of rust-lang#127660 - tgross35:const_strlen-rename, r=dt…
Unrolled build for rust-lang#127660