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(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// Library features:
97// tidy-alphabetical-start
98#![feature(array_ptr_get)]
99#![feature(asm_experimental_arch)]
100#![feature(bigint_helper_methods)]
101#![feature(bstr)]
102#![feature(bstr_internals)]
103#![feature(cfg_select)]
104#![feature(cfg_target_has_reliable_f16_f128)]
105#![feature(const_carrying_mul_add)]
106#![feature(const_cmp)]
107#![feature(const_destruct)]
108#![feature(const_eval_select)]
109#![feature(core_intrinsics)]
110#![feature(coverage_attribute)]
111#![feature(disjoint_bitor)]
112#![feature(internal_impls_macro)]
113#![feature(ip)]
114#![feature(is_ascii_octdigit)]
115#![feature(lazy_get)]
116#![feature(link_cfg)]
117#![feature(offset_of_enum)]
118#![feature(panic_internals)]
119#![feature(ptr_alignment_type)]
120#![feature(ptr_metadata)]
121#![feature(set_ptr_value)]
122#![feature(slice_as_array)]
123#![feature(slice_ptr_get)]
124#![feature(str_internals)]
125#![feature(str_split_inclusive_remainder)]
126#![feature(str_split_remainder)]
127#![feature(ub_checks)]
128#![feature(unchecked_neg)]
129#![feature(unchecked_shifts)]
130#![feature(unsafe_pinned)]
131#![feature(utf16_extra)]
132#![feature(variant_count)]
133// tidy-alphabetical-end
134//
135// Language features:
136// tidy-alphabetical-start
137#![feature(abi_unadjusted)]
138#![feature(adt_const_params)]
139#![feature(allow_internal_unsafe)]
140#![feature(allow_internal_unstable)]
141#![feature(auto_traits)]
142#![feature(cfg_sanitize)]
143#![feature(cfg_target_has_atomic)]
144#![feature(cfg_target_has_atomic_equal_alignment)]
145#![feature(cfg_ub_checks)]
146#![feature(const_precise_live_drops)]
147#![feature(const_trait_impl)]
148#![feature(decl_macro)]
149#![feature(deprecated_suggestion)]
150#![feature(derive_const)]
151#![feature(doc_cfg)]
152#![feature(doc_cfg_hide)]
153#![feature(doc_notable_trait)]
154#![feature(extern_types)]
155#![feature(f16)]
156#![feature(f128)]
157#![feature(freeze_impls)]
158#![feature(fundamental)]
159#![feature(if_let_guard)]
160#![feature(intra_doc_pointers)]
161#![feature(intrinsics)]
162#![feature(lang_items)]
163#![feature(link_llvm_intrinsics)]
164#![feature(macro_metavar_expr)]
165#![feature(macro_metavar_expr_concat)]
166#![feature(marker_trait_attr)]
167#![feature(min_specialization)]
168#![feature(multiple_supertrait_upcastable)]
169#![feature(must_not_suspend)]
170#![feature(negative_impls)]
171#![feature(never_type)]
172#![feature(no_core)]
173#![feature(optimize_attribute)]
174#![feature(prelude_import)]
175#![feature(repr_simd)]
176#![feature(rustc_allow_const_fn_unstable)]
177#![feature(rustc_attrs)]
178#![feature(rustdoc_internals)]
179#![feature(simd_ffi)]
180#![feature(staged_api)]
181#![feature(stmt_expr_attributes)]
182#![feature(strict_provenance_lints)]
183#![feature(trait_alias)]
184#![feature(transparent_unions)]
185#![feature(try_blocks)]
186#![feature(unboxed_closures)]
187#![feature(unsized_fn_params)]
188#![feature(with_negative_coherence)]
189// tidy-alphabetical-end
190//
191// Target features:
192// tidy-alphabetical-start
193#![feature(aarch64_unstable_target_feature)]
194#![feature(arm_target_feature)]
195#![feature(hexagon_target_feature)]
196#![feature(loongarch_target_feature)]
197#![feature(mips_target_feature)]
198#![feature(nvptx_target_feature)]
199#![feature(powerpc_target_feature)]
200#![feature(riscv_target_feature)]
201#![feature(rtm_target_feature)]
202#![feature(s390x_target_feature)]
203#![feature(wasm_target_feature)]
204#![feature(x86_amx_intrinsics)]
205// tidy-alphabetical-end
206
207// allow using `core::` in intra-doc links
208#[allow(unused_extern_crates)]
209extern crate self as core;
210
211/* The core prelude, not as all-encompassing as the std prelude */
212// The compiler expects the prelude definition to be defined before it's use statement.
213pub mod prelude;
214
215#[prelude_import]
216#[allow(unused)]
217use prelude::rust_2024::*;
218
219#[macro_use]
220mod macros;
221
222#[unstable(feature = "assert_matches", issue = "82775")]
223/// Unstable module containing the unstable `assert_matches` macro.
224pub mod assert_matches {
225    #[unstable(feature = "assert_matches", issue = "82775")]
226    pub use crate::macros::{assert_matches, debug_assert_matches};
227}
228
229#[unstable(feature = "derive_from", issue = "144889")]
230/// Unstable module containing the unstable `From` derive macro.
231pub mod from {
232    #[unstable(feature = "derive_from", issue = "144889")]
233    pub use crate::macros::builtin::From;
234}
235
236// We don't export this through #[macro_export] for now, to avoid breakage.
237#[unstable(feature = "autodiff", issue = "124509")]
238/// Unstable module containing the unstable `autodiff` macro.
239pub mod autodiff {
240    #[unstable(feature = "autodiff", issue = "124509")]
241    pub use crate::macros::builtin::{autodiff_forward, autodiff_reverse};
242}
243
244#[unstable(feature = "contracts", issue = "128044")]
245pub mod contracts;
246
247#[unstable(feature = "cfg_select", issue = "115585")]
248pub use crate::macros::cfg_select;
249
250#[macro_use]
251mod internal_macros;
252
253#[path = "num/shells/int_macros.rs"]
254#[macro_use]
255mod int_macros;
256
257#[rustc_diagnostic_item = "i128_legacy_mod"]
258#[path = "num/shells/i128.rs"]
259pub mod i128;
260#[rustc_diagnostic_item = "i16_legacy_mod"]
261#[path = "num/shells/i16.rs"]
262pub mod i16;
263#[rustc_diagnostic_item = "i32_legacy_mod"]
264#[path = "num/shells/i32.rs"]
265pub mod i32;
266#[rustc_diagnostic_item = "i64_legacy_mod"]
267#[path = "num/shells/i64.rs"]
268pub mod i64;
269#[rustc_diagnostic_item = "i8_legacy_mod"]
270#[path = "num/shells/i8.rs"]
271pub mod i8;
272#[rustc_diagnostic_item = "isize_legacy_mod"]
273#[path = "num/shells/isize.rs"]
274pub mod isize;
275
276#[rustc_diagnostic_item = "u128_legacy_mod"]
277#[path = "num/shells/u128.rs"]
278pub mod u128;
279#[rustc_diagnostic_item = "u16_legacy_mod"]
280#[path = "num/shells/u16.rs"]
281pub mod u16;
282#[rustc_diagnostic_item = "u32_legacy_mod"]
283#[path = "num/shells/u32.rs"]
284pub mod u32;
285#[rustc_diagnostic_item = "u64_legacy_mod"]
286#[path = "num/shells/u64.rs"]
287pub mod u64;
288#[rustc_diagnostic_item = "u8_legacy_mod"]
289#[path = "num/shells/u8.rs"]
290pub mod u8;
291#[rustc_diagnostic_item = "usize_legacy_mod"]
292#[path = "num/shells/usize.rs"]
293pub mod usize;
294
295#[path = "num/f128.rs"]
296pub mod f128;
297#[path = "num/f16.rs"]
298pub mod f16;
299#[path = "num/f32.rs"]
300pub mod f32;
301#[path = "num/f64.rs"]
302pub mod f64;
303
304#[macro_use]
305pub mod num;
306
307/* Core modules for ownership management */
308
309pub mod hint;
310pub mod intrinsics;
311pub mod mem;
312pub mod ptr;
313#[unstable(feature = "ub_checks", issue = "none")]
314pub mod ub_checks;
315
316/* Core language traits */
317
318pub mod borrow;
319pub mod clone;
320pub mod cmp;
321pub mod convert;
322pub mod default;
323pub mod error;
324pub mod marker;
325pub mod ops;
326
327/* Core types and methods on primitives */
328
329pub mod any;
330pub mod array;
331pub mod ascii;
332pub mod asserting;
333#[unstable(feature = "async_iterator", issue = "79024")]
334pub mod async_iter;
335#[unstable(feature = "bstr", issue = "134915")]
336pub mod bstr;
337pub mod cell;
338pub mod char;
339pub mod ffi;
340#[unstable(feature = "core_io_borrowed_buf", issue = "117693")]
341pub mod io;
342pub mod iter;
343pub mod net;
344pub mod option;
345pub mod panic;
346pub mod panicking;
347#[unstable(feature = "pattern_type_macro", issue = "123646")]
348pub mod pat;
349pub mod pin;
350#[unstable(feature = "random", issue = "130703")]
351pub mod random;
352#[unstable(feature = "new_range_api", issue = "125687")]
353pub mod range;
354pub mod result;
355pub mod sync;
356#[unstable(feature = "unsafe_binders", issue = "130516")]
357pub mod unsafe_binder;
358
359pub mod fmt;
360pub mod hash;
361pub mod slice;
362pub mod str;
363pub mod time;
364
365pub mod unicode;
366
367/* Async */
368pub mod future;
369pub mod task;
370
371/* Heap memory allocator trait */
372#[allow(missing_docs)]
373pub mod alloc;
374
375// note: does not need to be public
376mod bool;
377mod escape;
378mod tuple;
379mod unit;
380
381#[stable(feature = "core_primitive", since = "1.43.0")]
382pub mod primitive;
383
384// Pull in the `core_arch` crate directly into core. The contents of
385// `core_arch` are in a different repository: rust-lang/stdarch.
386//
387// `core_arch` depends on core, but the contents of this module are
388// set up in such a way that directly pulling it here works such that the
389// crate uses the this crate as its core.
390#[path = "../../stdarch/crates/core_arch/src/mod.rs"]
391#[allow(
392    missing_docs,
393    missing_debug_implementations,
394    dead_code,
395    unused_imports,
396    unsafe_op_in_unsafe_fn,
397    ambiguous_glob_reexports,
398    deprecated_in_future,
399    unreachable_pub
400)]
401#[allow(rustdoc::bare_urls)]
402mod core_arch;
403
404#[stable(feature = "simd_arch", since = "1.27.0")]
405pub mod arch;
406
407// Pull in the `core_simd` crate directly into core. The contents of
408// `core_simd` are in a different repository: rust-lang/portable-simd.
409//
410// `core_simd` depends on core, but the contents of this module are
411// set up in such a way that directly pulling it here works such that the
412// crate uses this crate as its core.
413#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
414#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
415#[allow(rustdoc::bare_urls)]
416#[unstable(feature = "portable_simd", issue = "86656")]
417mod core_simd;
418
419#[unstable(feature = "portable_simd", issue = "86656")]
420pub mod simd {
421    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
422
423    #[unstable(feature = "portable_simd", issue = "86656")]
424    pub use crate::core_simd::simd::*;
425}
426
427include!("primitive_docs.rs");