core/
lib.rs

1//! # The Rust Core Library
2//!
3//! The Rust Core Library is the dependency-free[^free] foundation of [The
4//! Rust Standard Library](../std/index.html). It is the portable glue
5//! between the language and its libraries, defining the intrinsic and
6//! primitive building blocks of all Rust code. It links to no
7//! upstream libraries, no system libraries, and no libc.
8//!
9//! [^free]: Strictly speaking, there are some symbols which are needed but
10//!          they aren't always necessary.
11//!
12//! The core library is *minimal*: it isn't even aware of heap allocation,
13//! nor does it provide concurrency or I/O. These things require
14//! platform integration, and this library is platform-agnostic.
15//!
16//! # How to use the core library
17//!
18//! Please note that all of these details are currently not considered stable.
19//!
20// FIXME: Fill me in with more detail when the interface settles
21//! This library is built on the assumption of a few existing symbols:
22//!
23//! * `memcpy`, `memmove`, `memset`, `memcmp`, `bcmp`, `strlen` - These are core memory routines
24//!   which are generated by Rust codegen backends. Additionally, this library can make explicit
25//!   calls to `strlen`. Their signatures are the same as found in C, but there are extra
26//!   assumptions about their semantics: For `memcpy`, `memmove`, `memset`, `memcmp`, and `bcmp`, if
27//!   the `n` parameter is 0, the function is assumed to not be UB, even if the pointers are NULL or
28//!   dangling. (Note that making extra assumptions about these functions is common among compilers:
29//!   [clang](https://reviews.llvm.org/D86993) and [GCC](https://gcc.gnu.org/onlinedocs/gcc/Standards.html#C-Language) do the same.)
30//!   These functions are often provided by the system libc, but can also be provided by the
31//!   [compiler-builtins crate](https://crates.io/crates/compiler_builtins).
32//!   Note that the library does not guarantee that it will always make these assumptions, so Rust
33//!   user code directly calling the C functions should follow the C specification! The advice for
34//!   Rust user code is to call the functions provided by this library instead (such as
35//!   `ptr::copy`).
36//!
37//! * Panic handler - This function takes one argument, a `&panic::PanicInfo`. It is up to consumers of this core
38//!   library to define this panic function; it is only required to never
39//!   return. You should mark your implementation using `#[panic_handler]`.
40//!
41//! * `rust_eh_personality` - is used by the failure mechanisms of the
42//!   compiler. This is often mapped to GCC's personality function, but crates
43//!   which do not trigger a panic can be assured that this function is never
44//!   called. The `lang` attribute is called `eh_personality`.
45
46#![stable(feature = "core", since = "1.6.0")]
47#![doc(
48    html_playground_url = "https://play.rust-lang.org/",
49    issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
50    test(no_crate_inject, attr(deny(warnings))),
51    test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
52)]
53#![doc(rust_logo)]
54#![doc(auto_cfg(hide(
55    no_fp_fmt_parse,
56    target_pointer_width = "16",
57    target_pointer_width = "32",
58    target_pointer_width = "64",
59    target_has_atomic = "8",
60    target_has_atomic = "16",
61    target_has_atomic = "32",
62    target_has_atomic = "64",
63    target_has_atomic = "ptr",
64    target_has_atomic_equal_alignment = "8",
65    target_has_atomic_equal_alignment = "16",
66    target_has_atomic_equal_alignment = "32",
67    target_has_atomic_equal_alignment = "64",
68    target_has_atomic_equal_alignment = "ptr",
69    target_has_atomic_load_store = "8",
70    target_has_atomic_load_store = "16",
71    target_has_atomic_load_store = "32",
72    target_has_atomic_load_store = "64",
73    target_has_atomic_load_store = "ptr",
74)))]
75#![no_core]
76#![rustc_coherence_is_core]
77#![rustc_preserve_ub_checks]
78//
79// Lints:
80#![deny(rust_2021_incompatible_or_patterns)]
81#![deny(unsafe_op_in_unsafe_fn)]
82#![deny(fuzzy_provenance_casts)]
83#![warn(deprecated_in_future)]
84#![warn(missing_debug_implementations)]
85#![warn(missing_docs)]
86#![allow(explicit_outlives_requirements)]
87#![allow(incomplete_features)]
88#![warn(multiple_supertrait_upcastable)]
89#![allow(internal_features)]
90#![deny(ffi_unwind_calls)]
91#![warn(unreachable_pub)]
92// Do not check link redundancy on bootstrapping phase
93#![allow(rustdoc::redundant_explicit_links)]
94#![warn(rustdoc::unescaped_backticks)]
95//
96// Ferrocene addition: We removed the tidy directives for alphabetical ordering to reduce the number
97// of conflicts we have when merging main.
98//
99// Library features:
100// not-alphabetical-start
101#![cfg_attr(not(feature = "ferrocene_subset"), feature(array_ptr_get))]
102#![cfg_attr(not(feature = "ferrocene_subset"), feature(asm_experimental_arch))]
103#![cfg_attr(not(feature = "ferrocene_subset"), feature(bigint_helper_methods))]
104#![cfg_attr(not(feature = "ferrocene_subset"), feature(bstr))]
105#![cfg_attr(not(feature = "ferrocene_subset"), feature(bstr_internals))]
106#![feature(cfg_select)]
107#![cfg_attr(not(feature = "ferrocene_subset"), feature(cfg_target_has_reliable_f16_f128))]
108#![cfg_attr(not(feature = "ferrocene_subset"), feature(const_carrying_mul_add))]
109#![cfg_attr(not(feature = "ferrocene_subset"), feature(const_cmp))]
110#![feature(const_destruct)]
111#![feature(const_eval_select)]
112#![cfg_attr(not(feature = "ferrocene_subset"), feature(const_select_unpredictable))]
113#![feature(core_intrinsics)]
114#![feature(coverage_attribute)]
115#![feature(disjoint_bitor)]
116#![feature(internal_impls_macro)]
117#![cfg_attr(not(feature = "ferrocene_subset"), feature(ip))]
118#![cfg_attr(not(feature = "ferrocene_subset"), feature(is_ascii_octdigit))]
119#![cfg_attr(not(feature = "ferrocene_subset"), feature(lazy_get))]
120#![cfg_attr(not(feature = "ferrocene_subset"), feature(link_cfg))]
121#![cfg_attr(not(feature = "ferrocene_subset"), feature(offset_of_enum))]
122#![feature(panic_internals)]
123#![cfg_attr(not(feature = "ferrocene_subset"), feature(ptr_alignment_type))]
124#![cfg_attr(not(feature = "ferrocene_subset"), feature(ptr_metadata))]
125#![cfg_attr(not(feature = "ferrocene_subset"), feature(set_ptr_value))]
126#![cfg_attr(not(feature = "ferrocene_subset"), feature(slice_ptr_get))]
127#![cfg_attr(not(feature = "ferrocene_subset"), feature(str_internals))]
128#![cfg_attr(not(feature = "ferrocene_subset"), feature(str_split_inclusive_remainder))]
129#![cfg_attr(not(feature = "ferrocene_subset"), feature(str_split_remainder))]
130#![cfg_attr(not(feature = "ferrocene_subset"), feature(pattern_type_macro))]
131#![feature(ub_checks)]
132#![cfg_attr(not(feature = "ferrocene_subset"), feature(unsafe_pinned))]
133#![cfg_attr(not(feature = "ferrocene_subset"), feature(utf16_extra))]
134#![cfg_attr(not(feature = "ferrocene_subset"), feature(variant_count))]
135// not-alphabetical-end
136//
137// Language features:
138// not-alphabetical-start
139#![feature(abi_unadjusted)]
140#![feature(adt_const_params)]
141#![feature(allow_internal_unsafe)]
142#![feature(allow_internal_unstable)]
143#![feature(auto_traits)]
144#![cfg_attr(not(feature = "ferrocene_subset"), feature(cfg_sanitize))]
145#![feature(cfg_target_has_atomic)]
146#![feature(cfg_target_has_atomic_equal_alignment)]
147#![feature(cfg_ub_checks)]
148#![feature(const_precise_live_drops)]
149#![feature(const_trait_impl)]
150#![feature(decl_macro)]
151#![feature(deprecated_suggestion)]
152#![feature(derive_const)]
153#![feature(diagnostic_on_const)]
154#![feature(doc_cfg)]
155#![cfg_attr(not(feature = "ferrocene_subset"), feature(doc_notable_trait))]
156#![feature(extern_types)]
157#![feature(f128)]
158#![feature(f16)]
159#![feature(freeze_impls)]
160#![feature(fundamental)]
161#![feature(funnel_shifts)]
162#![cfg_attr(not(feature = "ferrocene_subset"), feature(if_let_guard))]
163#![feature(intra_doc_pointers)]
164#![feature(intrinsics)]
165#![feature(lang_items)]
166#![feature(link_llvm_intrinsics)]
167#![feature(macro_metavar_expr)]
168#![cfg_attr(not(feature = "ferrocene_subset"), feature(macro_metavar_expr_concat))]
169#![feature(marker_trait_attr)]
170#![feature(min_specialization)]
171#![feature(multiple_supertrait_upcastable)]
172#![feature(must_not_suspend)]
173#![feature(negative_impls)]
174#![feature(never_type)]
175#![feature(no_core)]
176#![feature(optimize_attribute)]
177#![feature(pattern_types)]
178#![feature(prelude_import)]
179#![feature(reborrow)]
180#![feature(repr_simd)]
181#![feature(rustc_allow_const_fn_unstable)]
182#![feature(rustc_attrs)]
183#![feature(rustdoc_internals)]
184#![feature(simd_ffi)]
185#![feature(staged_api)]
186#![feature(stmt_expr_attributes)]
187#![feature(strict_provenance_lints)]
188#![feature(trait_alias)]
189#![feature(transparent_unions)]
190#![feature(try_blocks)]
191#![feature(unboxed_closures)]
192#![feature(unsized_fn_params)]
193#![cfg_attr(not(feature = "ferrocene_subset"), feature(with_negative_coherence))]
194// not-alphabetical-end
195//
196// Target features:
197// not-alphabetical-start
198#![cfg_attr(not(feature = "ferrocene_subset"), feature(aarch64_unstable_target_feature))]
199#![feature(arm_target_feature)]
200#![cfg_attr(not(feature = "ferrocene_subset"), feature(avx10_target_feature))]
201#![cfg_attr(not(feature = "ferrocene_subset"), feature(hexagon_target_feature))]
202#![cfg_attr(not(feature = "ferrocene_subset"), feature(loongarch_target_feature))]
203#![cfg_attr(not(feature = "ferrocene_subset"), feature(mips_target_feature))]
204#![cfg_attr(not(feature = "ferrocene_subset"), feature(powerpc_target_feature))]
205#![cfg_attr(not(feature = "ferrocene_subset"), feature(nvptx_target_feature))]
206#![cfg_attr(not(feature = "ferrocene_subset"), feature(riscv_target_feature))]
207#![cfg_attr(not(feature = "ferrocene_subset"), feature(rtm_target_feature))]
208#![cfg_attr(not(feature = "ferrocene_subset"), feature(s390x_target_feature))]
209#![cfg_attr(not(feature = "ferrocene_subset"), feature(wasm_target_feature))]
210#![cfg_attr(not(feature = "ferrocene_subset"), feature(x86_amx_intrinsics))]
211// not-alphabetical-end
212//
213// Ferrocene lints/features:
214#![cfg_attr(
215    feature = "ferrocene_subset",
216    expect(rustdoc::broken_intra_doc_links),
217    expect(rustdoc::private_intra_doc_links)
218)]
219#![feature(register_tool)]
220#![register_tool(ferrocene)]
221#![doc(auto_cfg(hide(feature = "ferrocene_subset")))]
222// Ferrocene addition: deals with all the unused code due to the lack of formatting machinery for
223// panics in the certified runtime
224#![cfg_attr(feature = "ferrocene_certified_runtime", expect(unused_variables))]
225
226// Ferrocene addition: ensure we don't instrument core without the certified panic
227#[cfg(all(ferrocene_coverage, not(feature = "ferrocene_certified_runtime")))]
228compile_error!("Cannot instrument core without the \"ferrocene_certified_runtime\" feature");
229
230// allow using `core::` in intra-doc links
231#[allow(unused_extern_crates)]
232extern crate self as core;
233
234/* The core prelude, not as all-encompassing as the std prelude */
235// The compiler expects the prelude definition to be defined before it's use statement.
236pub mod prelude;
237
238#[prelude_import]
239#[allow(unused)]
240use prelude::rust_2024::*;
241
242#[macro_use]
243mod macros;
244
245/// Ferrocene addition: Hidden module to test crate-internal functionality
246#[doc(hidden)]
247#[unstable(feature = "ferrocene_test", issue = "none")]
248#[cfg(not(feature = "ferrocene_subset"))]
249pub mod ferrocene_test;
250
251#[unstable(feature = "assert_matches", issue = "82775")]
252/// Unstable module containing the unstable `assert_matches` macro.
253#[cfg(not(feature = "ferrocene_subset"))]
254pub mod assert_matches {
255    #[unstable(feature = "assert_matches", issue = "82775")]
256    pub use crate::macros::{assert_matches, debug_assert_matches};
257}
258
259#[unstable(feature = "derive_from", issue = "144889")]
260/// Unstable module containing the unstable `From` derive macro.
261pub mod from {
262    #[unstable(feature = "derive_from", issue = "144889")]
263    pub use crate::macros::builtin::From;
264}
265
266// We don't export this through #[macro_export] for now, to avoid breakage.
267#[unstable(feature = "autodiff", issue = "124509")]
268/// Unstable module containing the unstable `autodiff` macro.
269pub mod autodiff {
270    #[unstable(feature = "autodiff", issue = "124509")]
271    pub use crate::macros::builtin::{autodiff_forward, autodiff_reverse};
272}
273
274#[unstable(feature = "contracts", issue = "128044")]
275#[cfg(not(feature = "ferrocene_subset"))]
276pub mod contracts;
277
278#[unstable(feature = "cfg_select", issue = "115585")]
279pub use crate::macros::cfg_select;
280
281#[macro_use]
282mod internal_macros;
283
284#[path = "num/shells/legacy_int_modules.rs"]
285#[cfg(not(feature = "ferrocene_subset"))]
286mod legacy_int_modules;
287#[stable(feature = "rust1", since = "1.0.0")]
288#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
289#[allow(deprecated_in_future)]
290#[cfg(not(feature = "ferrocene_subset"))]
291pub use legacy_int_modules::{i8, i16, i32, i64, isize, u8, u16, u32, u64, usize};
292#[stable(feature = "i128", since = "1.26.0")]
293#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
294#[allow(deprecated_in_future)]
295#[cfg(not(feature = "ferrocene_subset"))]
296pub use legacy_int_modules::{i128, u128};
297
298#[path = "num/f128.rs"]
299#[cfg(not(feature = "ferrocene_subset"))]
300pub mod f128;
301#[path = "num/f16.rs"]
302#[cfg(not(feature = "ferrocene_subset"))]
303pub mod f16;
304#[path = "num/f32.rs"]
305pub mod f32;
306#[path = "num/f64.rs"]
307pub mod f64;
308
309#[macro_use]
310pub mod num;
311
312/* Core modules for ownership management */
313
314pub mod hint;
315pub mod intrinsics;
316pub mod mem;
317#[unstable(feature = "profiling_marker_api", issue = "148197")]
318pub mod profiling;
319pub mod ptr;
320#[unstable(feature = "ub_checks", issue = "none")]
321pub mod ub_checks;
322
323/* Core language traits */
324
325pub mod borrow;
326pub mod clone;
327pub mod cmp;
328pub mod convert;
329pub mod default;
330#[cfg(not(feature = "ferrocene_subset"))]
331pub mod error;
332#[cfg(not(feature = "ferrocene_subset"))]
333pub mod index;
334pub mod marker;
335pub mod ops;
336
337/* Core types and methods on primitives */
338
339pub mod any;
340pub mod array;
341#[cfg(not(feature = "ferrocene_subset"))]
342pub mod ascii;
343#[cfg(not(feature = "ferrocene_subset"))]
344pub mod asserting;
345#[unstable(feature = "async_iterator", issue = "79024")]
346#[cfg(not(feature = "ferrocene_subset"))]
347pub mod async_iter;
348#[unstable(feature = "bstr", issue = "134915")]
349#[cfg(not(feature = "ferrocene_subset"))]
350pub mod bstr;
351pub mod cell;
352pub mod char;
353pub mod ffi;
354#[unstable(feature = "core_io_borrowed_buf", issue = "117693")]
355#[cfg(not(feature = "ferrocene_subset"))]
356pub mod io;
357pub mod iter;
358#[cfg(not(feature = "ferrocene_subset"))]
359pub mod net;
360pub mod option;
361#[cfg(not(feature = "ferrocene_subset"))]
362pub mod os;
363pub mod panic;
364pub mod panicking;
365#[unstable(feature = "pattern_type_macro", issue = "123646")]
366#[cfg(not(feature = "ferrocene_subset"))]
367pub mod pat;
368#[cfg(not(feature = "ferrocene_subset"))]
369pub mod pin;
370#[unstable(feature = "random", issue = "130703")]
371#[cfg(not(feature = "ferrocene_subset"))]
372pub mod random;
373#[unstable(feature = "new_range_api", issue = "125687")]
374#[cfg(not(feature = "ferrocene_subset"))]
375pub mod range;
376pub mod result;
377pub mod sync;
378#[unstable(feature = "unsafe_binders", issue = "130516")]
379#[cfg(not(feature = "ferrocene_subset"))]
380pub mod unsafe_binder;
381
382pub mod fmt;
383pub mod hash;
384pub mod slice;
385pub mod str;
386pub mod time;
387
388#[cfg(not(feature = "ferrocene_subset"))]
389pub mod wtf8;
390
391#[cfg(not(feature = "ferrocene_subset"))]
392pub mod unicode;
393
394/* Async */
395#[cfg(not(feature = "ferrocene_subset"))]
396pub mod future;
397#[cfg(not(feature = "ferrocene_subset"))]
398pub mod task;
399
400/* Heap memory allocator trait */
401#[allow(missing_docs)]
402pub mod alloc;
403
404// note: does not need to be public
405mod bool;
406#[cfg(not(feature = "ferrocene_subset"))]
407mod escape;
408mod tuple;
409#[cfg(not(feature = "ferrocene_subset"))]
410mod unit;
411
412#[stable(feature = "core_primitive", since = "1.43.0")]
413#[cfg(not(feature = "ferrocene_subset"))]
414pub mod primitive;
415
416// Pull in the `core_arch` crate directly into core. The contents of
417// `core_arch` are in a different repository: rust-lang/stdarch.
418//
419// `core_arch` depends on core, but the contents of this module are
420// set up in such a way that directly pulling it here works such that the
421// crate uses the this crate as its core.
422#[path = "../../stdarch/crates/core_arch/src/mod.rs"]
423#[allow(
424    missing_docs,
425    missing_debug_implementations,
426    dead_code,
427    unused_imports,
428    unsafe_op_in_unsafe_fn,
429    ambiguous_glob_reexports,
430    deprecated_in_future,
431    unreachable_pub
432)]
433#[allow(rustdoc::bare_urls)]
434mod core_arch;
435
436#[stable(feature = "simd_arch", since = "1.27.0")]
437pub mod arch;
438
439// Pull in the `core_simd` crate directly into core. The contents of
440// `core_simd` are in a different repository: rust-lang/portable-simd.
441//
442// `core_simd` depends on core, but the contents of this module are
443// set up in such a way that directly pulling it here works such that the
444// crate uses this crate as its core.
445#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
446#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
447#[allow(rustdoc::bare_urls)]
448#[unstable(feature = "portable_simd", issue = "86656")]
449#[cfg(not(feature = "ferrocene_subset"))]
450mod core_simd;
451
452#[unstable(feature = "portable_simd", issue = "86656")]
453#[cfg(not(feature = "ferrocene_subset"))]
454pub mod simd {
455    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
456
457    #[unstable(feature = "portable_simd", issue = "86656")]
458    pub use crate::core_simd::simd::*;
459}
460
461include!("primitive_docs.rs");
core/lib.rs

core/
lib.rs
