library/core/src/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`, `memcmp`, `memset` - These are core memory routines which are
  24 //!   often generated by LLVM. Additionally, this library can make explicit
  25 //!   calls to these functions. Their signatures are the same as found in C.
  26 //!   These functions are often provided by the system libc, but can also be
  27 //!   provided by the [compiler-builtins crate](https://crates.io/crates/compiler_builtins).
  28 //!
  29 //! * `rust_begin_panic` - This function takes four arguments, a
  30 //!   `fmt::Arguments`, a `&'static str`, and two `u32`'s. These four arguments
  31 //!   dictate the panic message, the file at which panic was invoked, and the
  32 //!   line and column inside the file. It is up to consumers of this core
  33 //!   library to define this panic function; it is only required to never
  34 //!   return. This requires a `lang` attribute named `panic_impl`.
  35 //!
  36 //! * `rust_eh_personality` - is used by the failure mechanisms of the
  37 //!    compiler. This is often mapped to GCC's personality function, but crates
  38 //!    which do not trigger a panic can be assured that this function is never
  39 //!    called. The `lang` attribute is called `eh_personality`.
  40
  41 // Since libcore defines many fundamental lang items, all tests live in a
  42 // separate crate, libcoretest, to avoid bizarre issues.
  43 //
  44 // Here we explicitly #[cfg]-out this whole crate when testing. If we don't do
  45 // this, both the generated test artifact and the linked libtest (which
  46 // transitively includes libcore) will both define the same set of lang items,
  47 // and this will cause the E0152 "found duplicate lang item" error. See
  48 // discussion in #50466 for details.
  49 //
  50 // This cfg won't affect doc tests.
  51 #![cfg(not(test))]
  52 #![stable(feature = "core", since = "1.6.0")]
  53 #![doc(
  54     html_playground_url = "https://play.rust-lang.org/",
  55     issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
  56     test(no_crate_inject, attr(deny(warnings))),
  57     test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
  58 )]
  59 #![no_core]
  60 #![warn(deprecated_in_future)]
  61 #![warn(missing_docs)]
  62 #![warn(missing_debug_implementations)]
  63 #![allow(explicit_outlives_requirements)]
  64 #![feature(rustc_allow_const_fn_unstable)]
  65 #![feature(allow_internal_unstable)]
  66 #![feature(arbitrary_self_types)]
  67 #![feature(asm)]
  68 #![feature(cfg_target_has_atomic)]
  69 #![feature(const_heap)]
  70 #![feature(const_alloc_layout)]
  71 #![feature(const_assert_type)]
  72 #![feature(const_discriminant)]
  73 #![feature(const_cell_into_inner)]
  74 #![feature(const_intrinsic_copy)]
  75 #![feature(const_intrinsic_forget)]
  76 #![feature(const_float_classify)]
  77 #![feature(const_float_bits_conv)]
  78 #![feature(const_int_unchecked_arith)]
  79 #![feature(const_inherent_unchecked_arith)]
  80 #![feature(const_mut_refs)]
  81 #![feature(const_refs_to_cell)]
  82 #![feature(const_panic)]
  83 #![feature(const_pin)]
  84 #![feature(const_fn_union)]
  85 #![feature(const_impl_trait)]
  86 #![feature(const_fn_floating_point_arithmetic)]
  87 #![feature(const_fn_fn_ptr_basics)]
  88 #![feature(const_fn_trait_bound)]
  89 #![cfg_attr(bootstrap, feature(const_fn))]
  90 #![feature(const_option)]
  91 #![feature(const_precise_live_drops)]
  92 #![feature(const_ptr_offset)]
  93 #![feature(const_ptr_offset_from)]
  94 #![feature(const_ptr_read)]
  95 #![feature(const_ptr_write)]
  96 #![feature(const_raw_ptr_comparison)]
  97 #![feature(const_raw_ptr_deref)]
  98 #![feature(const_slice_from_raw_parts)]
  99 #![feature(const_slice_ptr_len)]
 100 #![feature(const_size_of_val)]
 101 #![feature(const_swap)]
 102 #![feature(const_align_of_val)]
 103 #![feature(const_type_id)]
 104 #![feature(const_type_name)]
 105 #![feature(const_likely)]
 106 #![feature(const_unreachable_unchecked)]
 107 #![feature(const_maybe_uninit_assume_init)]
 108 #![feature(const_maybe_uninit_as_ptr)]
 109 #![feature(custom_inner_attributes)]
 110 #![feature(decl_macro)]
 111 #![feature(doc_cfg)]
 112 #![feature(doc_notable_trait)]
 113 #![feature(duration_consts_2)]
 114 #![cfg_attr(bootstrap, feature(extended_key_value_attributes))]
 115 #![feature(extern_types)]
 116 #![feature(fundamental)]
 117 #![feature(intra_doc_pointers)]
 118 #![feature(intrinsics)]
 119 #![feature(lang_items)]
 120 #![feature(link_llvm_intrinsics)]
 121 #![feature(llvm_asm)]
 122 #![feature(negative_impls)]
 123 #![feature(never_type)]
 124 #![feature(nll)]
 125 #![feature(exhaustive_patterns)]
 126 #![feature(no_core)]
 127 #![feature(auto_traits)]
 128 #![feature(prelude_import)]
 129 #![feature(ptr_metadata)]
 130 #![feature(repr_simd, platform_intrinsics)]
 131 #![feature(rustc_attrs)]
 132 #![feature(simd_ffi)]
 133 #![feature(min_specialization)]
 134 #![feature(staged_api)]
 135 #![feature(std_internals)]
 136 #![feature(stmt_expr_attributes)]
 137 #![feature(str_split_as_str)]
 138 #![feature(str_split_inclusive_as_str)]
 139 #![feature(char_indices_offset)]
 140 #![feature(trait_alias)]
 141 #![feature(transparent_unions)]
 142 #![feature(try_blocks)]
 143 #![feature(unboxed_closures)]
 144 #![feature(unsized_fn_params)]
 145 #![feature(unwind_attributes)]
 146 #![feature(variant_count)]
 147 #![feature(tbm_target_feature)]
 148 #![feature(sse4a_target_feature)]
 149 #![feature(arm_target_feature)]
 150 #![feature(powerpc_target_feature)]
 151 #![feature(mips_target_feature)]
 152 #![feature(aarch64_target_feature)]
 153 #![feature(wasm_target_feature)]
 154 #![feature(avx512_target_feature)]
 155 #![feature(cmpxchg16b_target_feature)]
 156 #![feature(rtm_target_feature)]
 157 #![feature(f16c_target_feature)]
 158 #![feature(hexagon_target_feature)]
 159 #![feature(const_fn_transmute)]
 160 #![feature(abi_unadjusted)]
 161 #![feature(adx_target_feature)]
 162 #![feature(external_doc)]
 163 #![feature(associated_type_bounds)]
 164 #![feature(const_caller_location)]
 165 #![feature(slice_ptr_get)]
 166 #![feature(no_niche)] // rust-lang/rust#68303
 167 #![feature(no_coverage)] // rust-lang/rust#84605
 168 #![feature(int_error_matching)]
 169 #![deny(unsafe_op_in_unsafe_fn)]
 170 #![deny(or_patterns_back_compat)]
 171
 172 // allow using `core::` in intra-doc links
 173 #[allow(unused_extern_crates)]
 174 extern crate self as core;
 175
 176 #[prelude_import]
 177 #[allow(unused)]
 178 use prelude::v1::*;
 179
 180 #[cfg(not(test))] // See #65860
 181 #[macro_use]
 182 mod macros;
 183
 184 #[macro_use]
 185 mod internal_macros;
 186
 187 #[path = "num/shells/int_macros.rs"]
 188 #[macro_use]
 189 mod int_macros;
 190
 191 #[path = "num/shells/i128.rs"]
 192 pub mod i128;
 193 #[path = "num/shells/i16.rs"]
 194 pub mod i16;
 195 #[path = "num/shells/i32.rs"]
 196 pub mod i32;
 197 #[path = "num/shells/i64.rs"]
 198 pub mod i64;
 199 #[path = "num/shells/i8.rs"]
 200 pub mod i8;
 201 #[path = "num/shells/isize.rs"]
 202 pub mod isize;
 203
 204 #[path = "num/shells/u128.rs"]
 205 pub mod u128;
 206 #[path = "num/shells/u16.rs"]
 207 pub mod u16;
 208 #[path = "num/shells/u32.rs"]
 209 pub mod u32;
 210 #[path = "num/shells/u64.rs"]
 211 pub mod u64;
 212 #[path = "num/shells/u8.rs"]
 213 pub mod u8;
 214 #[path = "num/shells/usize.rs"]
 215 pub mod usize;
 216
 217 #[path = "num/f32.rs"]
 218 pub mod f32;
 219 #[path = "num/f64.rs"]
 220 pub mod f64;
 221
 222 #[macro_use]
 223 pub mod num;
 224
 225 /* The libcore prelude, not as all-encompassing as the libstd prelude */
 226
 227 pub mod prelude;
 228
 229 /* Core modules for ownership management */
 230
 231 pub mod hint;
 232 pub mod intrinsics;
 233 pub mod mem;
 234 pub mod ptr;
 235
 236 /* Core language traits */
 237
 238 pub mod borrow;
 239 pub mod clone;
 240 pub mod cmp;
 241 pub mod convert;
 242 pub mod default;
 243 pub mod marker;
 244 pub mod ops;
 245
 246 /* Core types and methods on primitives */
 247
 248 pub mod any;
 249 pub mod array;
 250 pub mod ascii;
 251 pub mod cell;
 252 pub mod char;
 253 pub mod ffi;
 254 pub mod iter;
 255 #[unstable(feature = "once_cell", issue = "74465")]
 256 pub mod lazy;
 257 pub mod option;
 258 pub mod panic;
 259 pub mod panicking;
 260 pub mod pin;
 261 pub mod raw;
 262 pub mod result;
 263 #[unstable(feature = "async_stream", issue = "79024")]
 264 pub mod stream;
 265 pub mod sync;
 266
 267 pub mod fmt;
 268 pub mod hash;
 269 pub mod slice;
 270 pub mod str;
 271 pub mod time;
 272
 273 pub mod unicode;
 274
 275 /* Async */
 276 pub mod future;
 277 pub mod task;
 278
 279 /* Heap memory allocator trait */
 280 #[allow(missing_docs)]
 281 pub mod alloc;
 282
 283 // note: does not need to be public
 284 mod bool;
 285 mod tuple;
 286 mod unit;
 287
 288 #[stable(feature = "core_primitive", since = "1.43.0")]
 289 pub mod primitive;
 290
 291 // Pull in the `core_arch` crate directly into libcore. The contents of
 292 // `core_arch` are in a different repository: rust-lang/stdarch.
 293 //
 294 // `core_arch` depends on libcore, but the contents of this module are
 295 // set up in such a way that directly pulling it here works such that the
 296 // crate uses the this crate as its libcore.
 297 #[path = "../../stdarch/crates/core_arch/src/mod.rs"]
 298 #[allow(
 299     missing_docs,
 300     missing_debug_implementations,
 301     dead_code,
 302     unused_imports,
 303     unsafe_op_in_unsafe_fn
 304 )]
 305 #[allow(rustdoc::bare_urls)]
 306 // FIXME: This annotation should be moved into rust-lang/stdarch after clashing_extern_declarations is
 307 // merged. It currently cannot because bootstrap fails as the lint hasn't been defined yet.
 308 #[allow(clashing_extern_declarations)]
 309 #[unstable(feature = "stdsimd", issue = "48556")]
 310 mod core_arch;
 311
 312 #[stable(feature = "simd_arch", since = "1.27.0")]
 313 pub use core_arch::arch;