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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, duplicate_features)))
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#![allow(unused_features)]
91#![deny(ffi_unwind_calls)]
92#![warn(unreachable_pub)]
93// Do not check link redundancy on bootstrapping phase
94#![allow(rustdoc::redundant_explicit_links)]
95#![warn(rustdoc::unescaped_backticks)]
96//
97// Library features:
98// tidy-alphabetical-start
99#![feature(asm_experimental_arch)]
100#![feature(bstr_internals)]
101#![feature(cfg_target_has_reliable_f16_f128)]
102#![feature(const_carrying_mul_add)]
103#![feature(const_cmp)]
104#![feature(const_destruct)]
105#![feature(const_eval_select)]
106#![feature(const_select_unpredictable)]
107#![feature(core_intrinsics)]
108#![feature(coverage_attribute)]
109#![feature(disjoint_bitor)]
110#![feature(offset_of_enum)]
111#![feature(panic_internals)]
112#![feature(pattern_type_macro)]
113#![feature(sealed)]
114#![feature(ub_checks)]
115// tidy-alphabetical-end
116//
117// Language features:
118// tidy-alphabetical-start
119#![feature(abi_unadjusted)]
120#![feature(adt_const_params)]
121#![feature(allow_internal_unsafe)]
122#![feature(allow_internal_unstable)]
123#![feature(auto_traits)]
124#![feature(cfg_sanitize)]
125#![feature(cfg_target_has_atomic)]
126#![feature(cfg_target_has_atomic_equal_alignment)]
127#![feature(cfg_ub_checks)]
128#![feature(const_precise_live_drops)]
129#![feature(const_trait_impl)]
130#![feature(decl_macro)]
131#![feature(deprecated_suggestion)]
132#![feature(derive_const)]
133#![feature(diagnostic_on_const)]
134#![feature(diagnostic_on_unmatch_args)]
135#![feature(doc_cfg)]
136#![feature(doc_notable_trait)]
137#![feature(extern_types)]
138#![feature(f16)]
139#![feature(f128)]
140#![feature(field_projections)]
141#![feature(freeze_impls)]
142#![feature(fundamental)]
143#![feature(funnel_shifts)]
144#![feature(intra_doc_pointers)]
145#![feature(intrinsics)]
146#![feature(lang_items)]
147#![feature(link_cfg)]
148#![feature(link_llvm_intrinsics)]
149#![feature(macro_metavar_expr)]
150#![feature(macro_metavar_expr_concat)]
151#![feature(marker_trait_attr)]
152#![feature(min_specialization)]
153#![feature(multiple_supertrait_upcastable)]
154#![feature(must_not_suspend)]
155#![feature(negative_impls)]
156#![feature(never_type)]
157#![feature(no_core)]
158#![feature(optimize_attribute)]
159#![feature(pattern_types)]
160#![feature(pin_macro_internals)]
161#![feature(prelude_import)]
162#![feature(repr_simd)]
163#![feature(rustc_attrs)]
164#![feature(rustdoc_internals)]
165#![feature(simd_ffi)]
166#![feature(staged_api)]
167#![feature(stmt_expr_attributes)]
168#![feature(strict_provenance_lints)]
169#![feature(target_feature_inline_always)]
170#![feature(trait_alias)]
171#![feature(transparent_unions)]
172#![feature(try_blocks)]
173#![feature(uint_carryless_mul)]
174#![feature(unboxed_closures)]
175#![feature(unsized_fn_params)]
176#![feature(with_negative_coherence)]
177// tidy-alphabetical-end
178//
179// Target features:
180// tidy-alphabetical-start
181#![feature(aarch64_unstable_target_feature)]
182#![feature(arm_target_feature)]
183#![feature(avx10_target_feature)]
184#![feature(hexagon_target_feature)]
185#![feature(loongarch_target_feature)]
186#![feature(mips_target_feature)]
187#![feature(movrs_target_feature)]
188#![feature(nvptx_target_feature)]
189#![feature(powerpc_target_feature)]
190#![feature(riscv_target_feature)]
191#![feature(rtm_target_feature)]
192#![feature(s390x_target_feature)]
193#![feature(wasm_target_feature)]
194#![feature(x86_amx_intrinsics)]
195// tidy-alphabetical-end
196
197// allow using `core::` in intra-doc links
198#[allow(unused_extern_crates)]
199extern crate self as core;
200
201/* The core prelude, not as all-encompassing as the std prelude */
202// The compiler expects the prelude definition to be defined before it's use statement.
203pub mod prelude;
204
205#[prelude_import]
206#[allow(unused)]
207use prelude::rust_2024::*;
208
209#[macro_use]
210mod macros;
211
212#[stable(feature = "assert_matches", since = "1.95.0")]
213pub use crate::macros::{assert_matches, debug_assert_matches};
214
215#[unstable(feature = "derive_from", issue = "144889")]
216/// Unstable module containing the unstable `From` derive macro.
217pub mod from {
218    #[unstable(feature = "derive_from", issue = "144889")]
219    pub use crate::macros::builtin::From;
220}
221
222mod sealed {
223    /// This trait being unreachable from outside the crate
224    /// prevents outside implementations of our extension traits.
225    /// This allows adding more trait methods in the future.
226    #[unstable(feature = "sealed", issue = "none")]
227    pub trait Sealed {}
228}
229
230// We don't export this through #[macro_export] for now, to avoid breakage.
231#[unstable(feature = "autodiff", issue = "124509")]
232#[doc = include_str!("../../core/src/autodiff.md")]
233pub mod autodiff {
234    #[unstable(feature = "autodiff", issue = "124509")]
235    pub use crate::macros::builtin::{autodiff_forward, autodiff_reverse};
236}
237
238#[unstable(feature = "contracts", issue = "128044")]
239pub mod contracts;
240
241#[unstable(feature = "derive_macro_global_path", issue = "154645")]
242pub use crate::macros::builtin::derive;
243#[stable(feature = "cfg_select", since = "1.95.0")]
244pub use crate::macros::cfg_select;
245
246#[macro_use]
247mod internal_macros;
248
249#[path = "num/shells/legacy_int_modules.rs"]
250mod legacy_int_modules;
251#[stable(feature = "rust1", since = "1.0.0")]
252#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
253#[allow(deprecated_in_future)]
254pub use legacy_int_modules::{i8, i16, i32, i64, isize, u8, u16, u32, u64, usize};
255#[stable(feature = "i128", since = "1.26.0")]
256#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
257#[allow(deprecated_in_future)]
258pub use legacy_int_modules::{i128, u128};
259
260#[path = "num/f128.rs"]
261pub mod f128;
262#[path = "num/f16.rs"]
263pub mod f16;
264#[path = "num/f32.rs"]
265pub mod f32;
266#[path = "num/f64.rs"]
267pub mod f64;
268
269#[macro_use]
270pub mod num;
271
272/* Core modules for ownership management */
273
274pub mod hint;
275pub mod intrinsics;
276pub mod mem;
277#[unstable(feature = "profiling_marker_api", issue = "148197")]
278pub mod profiling;
279pub mod ptr;
280#[unstable(feature = "ub_checks", issue = "none")]
281pub mod ub_checks;
282
283/* Core language traits */
284
285pub mod borrow;
286pub mod clone;
287pub mod cmp;
288pub mod convert;
289pub mod default;
290pub mod error;
291#[unstable(feature = "field_projections", issue = "145383")]
292pub mod field;
293pub mod index;
294pub mod marker;
295pub mod ops;
296
297/* Core types and methods on primitives */
298
299pub mod any;
300pub mod array;
301pub mod ascii;
302pub mod asserting;
303#[unstable(feature = "async_iterator", issue = "79024")]
304pub mod async_iter;
305#[unstable(feature = "bstr", issue = "134915")]
306pub mod bstr;
307pub mod cell;
308pub mod char;
309pub mod ffi;
310#[unstable(feature = "core_io", issue = "154046")]
311pub mod io;
312pub mod iter;
313pub mod net;
314pub mod option;
315pub mod os;
316pub mod panic;
317pub mod panicking;
318#[unstable(feature = "pattern_type_macro", issue = "123646")]
319pub mod pat;
320pub mod pin;
321#[unstable(feature = "abort_immediate", issue = "154601")]
322pub mod process;
323#[unstable(feature = "random", issue = "130703")]
324pub mod random;
325#[stable(feature = "new_range_inclusive_api", since = "1.95.0")]
326pub mod range;
327pub mod result;
328pub mod sync;
329#[unstable(feature = "unsafe_binders", issue = "130516")]
330pub mod unsafe_binder;
331
332pub mod fmt;
333pub mod hash;
334pub mod slice;
335pub mod str;
336pub mod time;
337
338pub mod wtf8;
339
340pub mod unicode;
341
342/* Async */
343pub mod future;
344pub mod task;
345
346/* Heap memory allocator trait */
347#[allow(missing_docs)]
348pub mod alloc;
349
350// note: does not need to be public
351mod bool;
352mod escape;
353mod tuple;
354mod unit;
355
356#[stable(feature = "core_primitive", since = "1.43.0")]
357pub mod primitive;
358
359// Pull in the `core_arch` crate directly into core. The contents of
360// `core_arch` are in a different repository: rust-lang/stdarch.
361//
362// `core_arch` depends on core, but the contents of this module are
363// set up in such a way that directly pulling it here works such that the
364// crate uses the this crate as its core.
365#[path = "../../stdarch/crates/core_arch/src/mod.rs"]
366#[allow(
367    missing_docs,
368    missing_debug_implementations,
369    dead_code,
370    unused_imports,
371    unsafe_op_in_unsafe_fn,
372    ambiguous_glob_reexports,
373    deprecated_in_future,
374    unreachable_pub
375)]
376#[allow(rustdoc::bare_urls)]
377mod core_arch;
378
379#[stable(feature = "simd_arch", since = "1.27.0")]
380pub mod arch;
381
382// Pull in the `core_simd` crate directly into core. The contents of
383// `core_simd` are in a different repository: rust-lang/portable-simd.
384//
385// `core_simd` depends on core, but the contents of this module are
386// set up in such a way that directly pulling it here works such that the
387// crate uses this crate as its core.
388#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
389#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
390#[allow(rustdoc::bare_urls)]
391#[unstable(feature = "portable_simd", issue = "86656")]
392mod core_simd;
393
394#[unstable(feature = "portable_simd", issue = "86656")]
395pub mod simd {
396    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
397
398    #[unstable(feature = "portable_simd", issue = "86656")]
399    pub use crate::core_simd::simd::*;
400}
401
402include!("primitive_docs.rs");