lib.rs - source
Description: Source of the Rust file `library/core/src/lib.rs`.

#
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// 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(const_select_unpredictable)]
    110#![feature(core_intrinsics)]
    111#![feature(coverage_attribute)]
    112#![feature(disjoint_bitor)]
    113#![feature(internal_impls_macro)]
    114#![feature(ip)]
    115#![feature(is_ascii_octdigit)]
    116#![feature(link_cfg)]
    117#![feature(offset_of_enum)]
    118#![feature(panic_internals)]
    119#![feature(pattern_type_macro)]
    120#![feature(ptr_alignment_type)]
    121#![feature(ptr_metadata)]
    122#![feature(set_ptr_value)]
    123#![feature(slice_ptr_get)]
    124#![feature(str_internals)]
    125#![feature(str_split_inclusive_remainder)]
    126#![feature(str_split_remainder)]
    127#![feature(type_info)]
    128#![feature(ub_checks)]
    129#![feature(unsafe_pinned)]
    130#![feature(utf16_extra)]
    131#![feature(variant_count)]
    132// tidy-alphabetical-end
    133//
    134// Language features:
    135// tidy-alphabetical-start
    136#![feature(abi_unadjusted)]
    137#![feature(adt_const_params)]
    138#![feature(allow_internal_unsafe)]
    139#![feature(allow_internal_unstable)]
    140#![feature(auto_traits)]
    141#![feature(cfg_sanitize)]
    142#![feature(cfg_target_has_atomic)]
    143#![feature(cfg_target_has_atomic_equal_alignment)]
    144#![feature(cfg_ub_checks)]
    145#![feature(const_precise_live_drops)]
    146#![feature(const_trait_impl)]
    147#![feature(decl_macro)]
    148#![feature(deprecated_suggestion)]
    149#![feature(derive_const)]
    150#![feature(diagnostic_on_const)]
    151#![feature(doc_cfg)]
    152#![feature(doc_notable_trait)]
    153#![feature(extern_types)]
    154#![feature(f16)]
    155#![feature(f128)]
    156#![feature(freeze_impls)]
    157#![feature(fundamental)]
    158#![feature(funnel_shifts)]
    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(pattern_types)]
    175#![feature(prelude_import)]
    176#![feature(reborrow)]
    177#![feature(repr_simd)]
    178#![feature(rustc_allow_const_fn_unstable)]
    179#![feature(rustc_attrs)]
    180#![feature(rustdoc_internals)]
    181#![feature(simd_ffi)]
    182#![feature(staged_api)]
    183#![feature(stmt_expr_attributes)]
    184#![feature(strict_provenance_lints)]
    185#![feature(trait_alias)]
    186#![feature(transparent_unions)]
    187#![feature(try_blocks)]
    188#![feature(unboxed_closures)]
    189#![feature(unsized_fn_params)]
    190#![feature(with_negative_coherence)]
    191// tidy-alphabetical-end
    192//
    193// Target features:
    194// tidy-alphabetical-start
    195#![feature(aarch64_unstable_target_feature)]
    196#![feature(arm_target_feature)]
    197#![feature(avx10_target_feature)]
    198#![feature(hexagon_target_feature)]
    199#![feature(loongarch_target_feature)]
    200#![feature(mips_target_feature)]
    201#![feature(nvptx_target_feature)]
    202#![feature(powerpc_target_feature)]
    203#![feature(riscv_target_feature)]
    204#![feature(rtm_target_feature)]
    205#![feature(s390x_target_feature)]
    206#![feature(wasm_target_feature)]
    207#![feature(x86_amx_intrinsics)]
    208// tidy-alphabetical-end
    209
    210// allow using `core::` in intra-doc links
    211#[allow(unused_extern_crates)]
    212extern crate self as core;
    213
    214/* The core prelude, not as all-encompassing as the std prelude */
    215// The compiler expects the prelude definition to be defined before it's use statement.
    216pub mod prelude;
    217
    218#[prelude_import]
    219#[allow(unused)]
    220use prelude::rust_2024::*;
    221
    222#[macro_use]
    223mod macros;
    224
    225#[unstable(feature = "assert_matches", issue = "82775")]
    226/// Unstable module containing the unstable `assert_matches` macro.
    227pub mod assert_matches {
    228    #[unstable(feature = "assert_matches", issue = "82775")]
    229    pub use crate::macros::{assert_matches, debug_assert_matches};
    230}
    231
    232#[unstable(feature = "derive_from", issue = "144889")]
    233/// Unstable module containing the unstable `From` derive macro.
    234pub mod from {
    235    #[unstable(feature = "derive_from", issue = "144889")]
    236    pub use crate::macros::builtin::From;
    237}
    238
    239// We don't export this through #[macro_export] for now, to avoid breakage.
    240#[unstable(feature = "autodiff", issue = "124509")]
    241/// Unstable module containing the unstable `autodiff` macro.
    242pub mod autodiff {
    243    #[unstable(feature = "autodiff", issue = "124509")]
    244    pub use crate::macros::builtin::{autodiff_forward, autodiff_reverse};
    245}
    246
    247#[unstable(feature = "contracts", issue = "128044")]
    248pub mod contracts;
    249
    250#[unstable(feature = "cfg_select", issue = "115585")]
    251pub use crate::macros::cfg_select;
    252
    253#[macro_use]
    254mod internal_macros;
    255
    256#[path = "num/shells/legacy_int_modules.rs"]
    257mod legacy_int_modules;
    258#[stable(feature = "rust1", since = "1.0.0")]
    259#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
    260#[allow(deprecated_in_future)]
    261pub use legacy_int_modules::{i8, i16, i32, i64, isize, u8, u16, u32, u64, usize};
    262#[stable(feature = "i128", since = "1.26.0")]
    263#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
    264#[allow(deprecated_in_future)]
    265pub use legacy_int_modules::{i128, u128};
    266
    267#[path = "num/f128.rs"]
    268pub mod f128;
    269#[path = "num/f16.rs"]
    270pub mod f16;
    271#[path = "num/f32.rs"]
    272pub mod f32;
    273#[path = "num/f64.rs"]
    274pub mod f64;
    275
    276#[macro_use]
    277pub mod num;
    278
    279/* Core modules for ownership management */
    280
    281pub mod hint;
    282pub mod intrinsics;
    283pub mod mem;
    284#[unstable(feature = "profiling_marker_api", issue = "148197")]
    285pub mod profiling;
    286pub mod ptr;
    287#[unstable(feature = "ub_checks", issue = "none")]
    288pub mod ub_checks;
    289
    290/* Core language traits */
    291
    292pub mod borrow;
    293pub mod clone;
    294pub mod cmp;
    295pub mod convert;
    296pub mod default;
    297pub mod error;
    298pub mod index;
    299pub mod marker;
    300pub mod ops;
    301
    302/* Core types and methods on primitives */
    303
    304pub mod any;
    305pub mod array;
    306pub mod ascii;
    307pub mod asserting;
    308#[unstable(feature = "async_iterator", issue = "79024")]
    309pub mod async_iter;
    310#[unstable(feature = "bstr", issue = "134915")]
    311pub mod bstr;
    312pub mod cell;
    313pub mod char;
    314pub mod ffi;
    315#[unstable(feature = "core_io_borrowed_buf", issue = "117693")]
    316pub mod io;
    317pub mod iter;
    318pub mod net;
    319pub mod option;
    320pub mod os;
    321pub mod panic;
    322pub mod panicking;
    323#[unstable(feature = "pattern_type_macro", issue = "123646")]
    324pub mod pat;
    325pub mod pin;
    326#[unstable(feature = "random", issue = "130703")]
    327pub mod random;
    328#[unstable(feature = "new_range_api", issue = "125687")]
    329pub mod range;
    330pub mod result;
    331pub mod sync;
    332#[unstable(feature = "unsafe_binders", issue = "130516")]
    333pub mod unsafe_binder;
    334
    335pub mod fmt;
    336pub mod hash;
    337pub mod slice;
    338pub mod str;
    339pub mod time;
    340
    341pub mod wtf8;
    342
    343pub mod unicode;
    344
    345/* Async */
    346pub mod future;
    347pub mod task;
    348
    349/* Heap memory allocator trait */
    350#[allow(missing_docs)]
    351pub mod alloc;
    352
    353// note: does not need to be public
    354mod bool;
    355mod escape;
    356mod tuple;
    357mod unit;
    358
    359#[stable(feature = "core_primitive", since = "1.43.0")]
    360pub mod primitive;
    361
    362// Pull in the `core_arch` crate directly into core. The contents of
    363// `core_arch` are in a different repository: rust-lang/stdarch.
    364//
    365// `core_arch` depends on core, but the contents of this module are
    366// set up in such a way that directly pulling it here works such that the
    367// crate uses the this crate as its core.
    368#[path = "../../stdarch/crates/core_arch/src/mod.rs"]
    369#[allow(
    370    missing_docs,
    371    missing_debug_implementations,
    372    dead_code,
    373    unused_imports,
    374    unsafe_op_in_unsafe_fn,
    375    ambiguous_glob_reexports,
    376    deprecated_in_future,
    377    unreachable_pub
    378)]
    379#[allow(rustdoc::bare_urls)]
    380mod core_arch;
    381
    382#[stable(feature = "simd_arch", since = "1.27.0")]
    383pub mod arch;
    384
    385// Pull in the `core_simd` crate directly into core. The contents of
    386// `core_simd` are in a different repository: rust-lang/portable-simd.
    387//
    388// `core_simd` depends on core, but the contents of this module are
    389// set up in such a way that directly pulling it here works such that the
    390// crate uses this crate as its core.
    391#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
    392#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
    393#[allow(rustdoc::bare_urls)]
    394#[unstable(feature = "portable_simd", issue = "86656")]
    395mod core_simd;
    396
    397#[unstable(feature = "portable_simd", issue = "86656")]
    398pub mod simd {
    399    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
    400
    401    #[unstable(feature = "portable_simd", issue = "86656")]
    402    pub use crate::core_simd::simd::*;
    403}
    404
    405include!("primitive_docs.rs");