#
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// We don't export this through #[macro_export] for now, to avoid breakage.
    230#[unstable(feature = "autodiff", issue = "124509")]
    231/// Unstable module containing the unstable `autodiff` macro.
    232pub mod autodiff {
    233    #[unstable(feature = "autodiff", issue = "124509")]
    234    pub use crate::macros::builtin::{autodiff_forward, autodiff_reverse};
    235}
    236
    237#[unstable(feature = "contracts", issue = "128044")]
    238pub mod contracts;
    239
    240#[unstable(feature = "cfg_select", issue = "115585")]
    241pub use crate::macros::cfg_select;
    242
    243#[macro_use]
    244mod internal_macros;
    245
    246#[path = "num/shells/int_macros.rs"]
    247#[macro_use]
    248mod int_macros;
    249
    250#[rustc_diagnostic_item = "i128_legacy_mod"]
    251#[path = "num/shells/i128.rs"]
    252pub mod i128;
    253#[rustc_diagnostic_item = "i16_legacy_mod"]
    254#[path = "num/shells/i16.rs"]
    255pub mod i16;
    256#[rustc_diagnostic_item = "i32_legacy_mod"]
    257#[path = "num/shells/i32.rs"]
    258pub mod i32;
    259#[rustc_diagnostic_item = "i64_legacy_mod"]
    260#[path = "num/shells/i64.rs"]
    261pub mod i64;
    262#[rustc_diagnostic_item = "i8_legacy_mod"]
    263#[path = "num/shells/i8.rs"]
    264pub mod i8;
    265#[rustc_diagnostic_item = "isize_legacy_mod"]
    266#[path = "num/shells/isize.rs"]
    267pub mod isize;
    268
    269#[rustc_diagnostic_item = "u128_legacy_mod"]
    270#[path = "num/shells/u128.rs"]
    271pub mod u128;
    272#[rustc_diagnostic_item = "u16_legacy_mod"]
    273#[path = "num/shells/u16.rs"]
    274pub mod u16;
    275#[rustc_diagnostic_item = "u32_legacy_mod"]
    276#[path = "num/shells/u32.rs"]
    277pub mod u32;
    278#[rustc_diagnostic_item = "u64_legacy_mod"]
    279#[path = "num/shells/u64.rs"]
    280pub mod u64;
    281#[rustc_diagnostic_item = "u8_legacy_mod"]
    282#[path = "num/shells/u8.rs"]
    283pub mod u8;
    284#[rustc_diagnostic_item = "usize_legacy_mod"]
    285#[path = "num/shells/usize.rs"]
    286pub mod usize;
    287
    288#[path = "num/f128.rs"]
    289pub mod f128;
    290#[path = "num/f16.rs"]
    291pub mod f16;
    292#[path = "num/f32.rs"]
    293pub mod f32;
    294#[path = "num/f64.rs"]
    295pub mod f64;
    296
    297#[macro_use]
    298pub mod num;
    299
    300/* Core modules for ownership management */
    301
    302pub mod hint;
    303pub mod intrinsics;
    304pub mod mem;
    305pub mod ptr;
    306#[unstable(feature = "ub_checks", issue = "none")]
    307pub mod ub_checks;
    308
    309/* Core language traits */
    310
    311pub mod borrow;
    312pub mod clone;
    313pub mod cmp;
    314pub mod convert;
    315pub mod default;
    316pub mod error;
    317pub mod marker;
    318pub mod ops;
    319
    320/* Core types and methods on primitives */
    321
    322pub mod any;
    323pub mod array;
    324pub mod ascii;
    325pub mod asserting;
    326#[unstable(feature = "async_iterator", issue = "79024")]
    327pub mod async_iter;
    328#[unstable(feature = "bstr", issue = "134915")]
    329pub mod bstr;
    330pub mod cell;
    331pub mod char;
    332pub mod ffi;
    333#[unstable(feature = "core_io_borrowed_buf", issue = "117693")]
    334pub mod io;
    335pub mod iter;
    336pub mod net;
    337pub mod option;
    338pub mod panic;
    339pub mod panicking;
    340#[unstable(feature = "pattern_type_macro", issue = "123646")]
    341pub mod pat;
    342pub mod pin;
    343#[unstable(feature = "random", issue = "130703")]
    344pub mod random;
    345#[unstable(feature = "new_range_api", issue = "125687")]
    346pub mod range;
    347pub mod result;
    348pub mod sync;
    349#[unstable(feature = "unsafe_binders", issue = "130516")]
    350pub mod unsafe_binder;
    351
    352pub mod fmt;
    353pub mod hash;
    354pub mod slice;
    355pub mod str;
    356pub mod time;
    357
    358pub mod unicode;
    359
    360/* Async */
    361pub mod future;
    362pub mod task;
    363
    364/* Heap memory allocator trait */
    365#[allow(missing_docs)]
    366pub mod alloc;
    367
    368// note: does not need to be public
    369mod bool;
    370mod escape;
    371mod tuple;
    372mod unit;
    373
    374#[stable(feature = "core_primitive", since = "1.43.0")]
    375pub mod primitive;
    376
    377// Pull in the `core_arch` crate directly into core. The contents of
    378// `core_arch` are in a different repository: rust-lang/stdarch.
    379//
    380// `core_arch` depends on core, but the contents of this module are
    381// set up in such a way that directly pulling it here works such that the
    382// crate uses the this crate as its core.
    383#[path = "../../stdarch/crates/core_arch/src/mod.rs"]
    384#[allow(
    385    missing_docs,
    386    missing_debug_implementations,
    387    dead_code,
    388    unused_imports,
    389    unsafe_op_in_unsafe_fn,
    390    ambiguous_glob_reexports,
    391    deprecated_in_future,
    392    unreachable_pub
    393)]
    394#[allow(rustdoc::bare_urls)]
    395mod core_arch;
    396
    397#[stable(feature = "simd_arch", since = "1.27.0")]
    398pub mod arch;
    399
    400// Pull in the `core_simd` crate directly into core. The contents of
    401// `core_simd` are in a different repository: rust-lang/portable-simd.
    402//
    403// `core_simd` depends on core, but the contents of this module are
    404// set up in such a way that directly pulling it here works such that the
    405// crate uses this crate as its core.
    406#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
    407#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
    408#[allow(rustdoc::bare_urls)]
    409#[unstable(feature = "portable_simd", issue = "86656")]
    410mod core_simd;
    411
    412#[unstable(feature = "portable_simd", issue = "86656")]
    413pub mod simd {
    414    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
    415
    416    #[unstable(feature = "portable_simd", issue = "86656")]
    417    pub use crate::core_simd::simd::*;
    418}
    419
    420include!("primitive_docs.rs");