std/
lib.rs

1//! # The Rust Standard Library
2//!
3//! The Rust Standard Library is the foundation of portable Rust software, a
4//! set of minimal and battle-tested shared abstractions for the [broader Rust
5//! ecosystem][crates.io]. It offers core types, like [`Vec<T>`] and
6//! [`Option<T>`], library-defined [operations on language
7//! primitives](#primitives), [standard macros](#macros), [I/O] and
8//! [multithreading], among [many other things][other].
9//!
10//! `std` is available to all Rust crates by default. Therefore, the
11//! standard library can be accessed in [`use`] statements through the path
12//! `std`, as in [`use std::env`].
13//!
14//! # How to read this documentation
15//!
16//! If you already know the name of what you are looking for, the fastest way to
17//! find it is to use the <a href="#" onclick="window.searchState.focus();">search
18//! bar</a> at the top of the page.
19//!
20//! Otherwise, you may want to jump to one of these useful sections:
21//!
22//! * [`std::*` modules](#modules)
23//! * [Primitive types](#primitives)
24//! * [Standard macros](#macros)
25//! * [The Rust Prelude]
26//!
27//! If this is your first time, the documentation for the standard library is
28//! written to be casually perused. Clicking on interesting things should
29//! generally lead you to interesting places. Still, there are important bits
30//! you don't want to miss, so read on for a tour of the standard library and
31//! its documentation!
32//!
33//! Once you are familiar with the contents of the standard library you may
34//! begin to find the verbosity of the prose distracting. At this stage in your
35//! development you may want to press the
36//! "<svg style="width:0.75rem;height:0.75rem" viewBox="0 0 12 12" stroke="currentColor" fill="none"><path d="M2,2l4,4l4,-4M2,6l4,4l4,-4"/></svg>&nbsp;Summary"
37//! button near the top of the page to collapse it into a more skimmable view.
38//!
39//! While you are looking at the top of the page, also notice the
40//! "Source" link. Rust's API documentation comes with the source
41//! code and you are encouraged to read it. The standard library source is
42//! generally high quality and a peek behind the curtains is
43//! often enlightening.
44//!
45//! # What is in the standard library documentation?
46//!
47//! First of all, The Rust Standard Library is divided into a number of focused
48//! modules, [all listed further down this page](#modules). These modules are
49//! the bedrock upon which all of Rust is forged, and they have mighty names
50//! like [`std::slice`] and [`std::cmp`]. Modules' documentation typically
51//! includes an overview of the module along with examples, and are a smart
52//! place to start familiarizing yourself with the library.
53//!
54//! Second, implicit methods on [primitive types] are documented here. This can
55//! be a source of confusion for two reasons:
56//!
57//! 1. While primitives are implemented by the compiler, the standard library
58//!    implements methods directly on the primitive types (and it is the only
59//!    library that does so), which are [documented in the section on
60//!    primitives](#primitives).
61//! 2. The standard library exports many modules *with the same name as
62//!    primitive types*. These define additional items related to the primitive
63//!    type, but not the all-important methods.
64//!
65//! So for example there is a [page for the primitive type
66//! `i32`](primitive::i32) that lists all the methods that can be called on
67//! 32-bit integers (very useful), and there is a [page for the module
68//! `std::i32`] that documents the constant values [`MIN`] and [`MAX`] (rarely
69//! useful).
70//!
71//! Note the documentation for the primitives [`str`] and [`[T]`][prim@slice] (also
72//! called 'slice'). Many method calls on [`String`] and [`Vec<T>`] are actually
73//! calls to methods on [`str`] and [`[T]`][prim@slice] respectively, via [deref
74//! coercions][deref-coercions].
75//!
76//! Third, the standard library defines [The Rust Prelude], a small collection
77//! of items - mostly traits - that are imported into every module of every
78//! crate. The traits in the prelude are pervasive, making the prelude
79//! documentation a good entry point to learning about the library.
80//!
81//! And finally, the standard library exports a number of standard macros, and
82//! [lists them on this page](#macros) (technically, not all of the standard
83//! macros are defined by the standard library - some are defined by the
84//! compiler - but they are documented here the same). Like the prelude, the
85//! standard macros are imported by default into all crates.
86//!
87//! # Contributing changes to the documentation
88//!
89//! Check out the Rust contribution guidelines [here](
90//! https://rustc-dev-guide.rust-lang.org/contributing.html#writing-documentation).
91//! The source for this documentation can be found on
92//! [GitHub](https://github.com/rust-lang/rust) in the 'library/std/' directory.
93//! To contribute changes, make sure you read the guidelines first, then submit
94//! pull-requests for your suggested changes.
95//!
96//! Contributions are appreciated! If you see a part of the docs that can be
97//! improved, submit a PR, or chat with us first on [Discord][rust-discord]
98//! #docs.
99//!
100//! # A Tour of The Rust Standard Library
101//!
102//! The rest of this crate documentation is dedicated to pointing out notable
103//! features of The Rust Standard Library.
104//!
105//! ## Containers and collections
106//!
107//! The [`option`] and [`result`] modules define optional and error-handling
108//! types, [`Option<T>`] and [`Result<T, E>`]. The [`iter`] module defines
109//! Rust's iterator trait, [`Iterator`], which works with the [`for`] loop to
110//! access collections.
111//!
112//! The standard library exposes three common ways to deal with contiguous
113//! regions of memory:
114//!
115//! * [`Vec<T>`] - A heap-allocated *vector* that is resizable at runtime.
116//! * [`[T; N]`][prim@array] - An inline *array* with a fixed size at compile time.
117//! * [`[T]`][prim@slice] - A dynamically sized *slice* into any other kind of contiguous
118//!   storage, whether heap-allocated or not.
119//!
120//! Slices can only be handled through some kind of *pointer*, and as such come
121//! in many flavors such as:
122//!
123//! * `&[T]` - *shared slice*
124//! * `&mut [T]` - *mutable slice*
125//! * [`Box<[T]>`][owned slice] - *owned slice*
126//!
127//! [`str`], a UTF-8 string slice, is a primitive type, and the standard library
128//! defines many methods for it. Rust [`str`]s are typically accessed as
129//! immutable references: `&str`. Use the owned [`String`] for building and
130//! mutating strings.
131//!
132//! For converting to strings use the [`format!`] macro, and for converting from
133//! strings use the [`FromStr`] trait.
134//!
135//! Data may be shared by placing it in a reference-counted box or the [`Rc`]
136//! type, and if further contained in a [`Cell`] or [`RefCell`], may be mutated
137//! as well as shared. Likewise, in a concurrent setting it is common to pair an
138//! atomically-reference-counted box, [`Arc`], with a [`Mutex`] to get the same
139//! effect.
140//!
141//! The [`collections`] module defines maps, sets, linked lists and other
142//! typical collection types, including the common [`HashMap<K, V>`].
143//!
144//! ## Platform abstractions and I/O
145//!
146//! Besides basic data types, the standard library is largely concerned with
147//! abstracting over differences in common platforms, most notably Windows and
148//! Unix derivatives.
149//!
150//! Common types of I/O, including [files], [TCP], and [UDP], are defined in
151//! the [`io`], [`fs`], and [`net`] modules.
152//!
153//! The [`thread`] module contains Rust's threading abstractions. [`sync`]
154//! contains further primitive shared memory types, including [`atomic`], [`mpmc`] and
155//! [`mpsc`], which contains the channel types for message passing.
156//!
157//! # Use before and after `main()`
158//!
159//! Many parts of the standard library are expected to work before and after `main()`;
160//! but this is not guaranteed or ensured by tests. It is recommended that you write your own tests
161//! and run them on each platform you wish to support.
162//! This means that use of `std` before/after main, especially of features that interact with the
163//! OS or global state, is exempted from stability and portability guarantees and instead only
164//! provided on a best-effort basis. Nevertheless bug reports are appreciated.
165//!
166//! On the other hand `core` and `alloc` are most likely to work in such environments with
167//! the caveat that any hookable behavior such as panics, oom handling or allocators will also
168//! depend on the compatibility of the hooks.
169//!
170//! Some features may also behave differently outside main, e.g. stdio could become unbuffered,
171//! some panics might turn into aborts, backtraces might not get symbolicated or similar.
172//!
173//! Non-exhaustive list of known limitations:
174//!
175//! - after-main use of thread-locals, which also affects additional features:
176//!   - [`thread::current()`]
177//! - under UNIX, before main, file descriptors 0, 1, and 2 may be unchanged
178//!   (they are guaranteed to be open during main,
179//!    and are opened to /dev/null O_RDWR if they weren't open on program start)
180//!
181//!
182//! [I/O]: io
183//! [`MIN`]: i32::MIN
184//! [`MAX`]: i32::MAX
185//! [page for the module `std::i32`]: crate::i32
186//! [TCP]: net::TcpStream
187//! [The Rust Prelude]: prelude
188//! [UDP]: net::UdpSocket
189//! [`Arc`]: sync::Arc
190//! [owned slice]: boxed
191//! [`Cell`]: cell::Cell
192//! [`FromStr`]: str::FromStr
193//! [`HashMap<K, V>`]: collections::HashMap
194//! [`Mutex`]: sync::Mutex
195//! [`Option<T>`]: option::Option
196//! [`Rc`]: rc::Rc
197//! [`RefCell`]: cell::RefCell
198//! [`Result<T, E>`]: result::Result
199//! [`Vec<T>`]: vec::Vec
200//! [`atomic`]: sync::atomic
201//! [`for`]: ../book/ch03-05-control-flow.html#looping-through-a-collection-with-for
202//! [`str`]: prim@str
203//! [`mpmc`]: sync::mpmc
204//! [`mpsc`]: sync::mpsc
205//! [`std::cmp`]: cmp
206//! [`std::slice`]: mod@slice
207//! [`use std::env`]: env/index.html
208//! [`use`]: ../book/ch07-02-defining-modules-to-control-scope-and-privacy.html
209//! [crates.io]: https://crates.io
210//! [deref-coercions]: ../book/ch15-02-deref.html#implicit-deref-coercions-with-functions-and-methods
211//! [files]: fs::File
212//! [multithreading]: thread
213//! [other]: #what-is-in-the-standard-library-documentation
214//! [primitive types]: ../book/ch03-02-data-types.html
215//! [rust-discord]: https://discord.gg/rust-lang
216//! [array]: prim@array
217//! [slice]: prim@slice
218
219#![cfg_attr(not(restricted_std), stable(feature = "rust1", since = "1.0.0"))]
220#![cfg_attr(
221    restricted_std,
222    unstable(
223        feature = "restricted_std",
224        issue = "none",
225        reason = "You have attempted to use a standard library built for a platform that it doesn't \
226            know how to support. Consider building it for a known environment, disabling it with \
227            `#![no_std]` or overriding this warning by enabling this feature."
228    )
229)]
230#![rustc_preserve_ub_checks]
231#![doc(
232    html_playground_url = "https://play.rust-lang.org/",
233    issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
234    test(no_crate_inject, attr(deny(warnings))),
235    test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
236)]
237#![doc(rust_logo)]
238#![doc(cfg_hide(not(test), no_global_oom_handling, not(no_global_oom_handling)))]
239// Don't link to std. We are std.
240#![no_std]
241// Tell the compiler to link to either panic_abort or panic_unwind
242#![needs_panic_runtime]
243//
244// Lints:
245#![warn(deprecated_in_future)]
246#![warn(missing_docs)]
247#![warn(missing_debug_implementations)]
248#![allow(explicit_outlives_requirements)]
249#![allow(unused_lifetimes)]
250#![allow(internal_features)]
251#![deny(fuzzy_provenance_casts)]
252#![deny(unsafe_op_in_unsafe_fn)]
253#![allow(rustdoc::redundant_explicit_links)]
254#![warn(rustdoc::unescaped_backticks)]
255// Ensure that std can be linked against panic_abort despite compiled with `-C panic=unwind`
256#![deny(ffi_unwind_calls)]
257// std may use features in a platform-specific way
258#![allow(unused_features)]
259//
260// Features:
261#![cfg_attr(test, feature(internal_output_capture, print_internals, update_panic_count, rt))]
262#![cfg_attr(
263    all(target_vendor = "fortanix", target_env = "sgx"),
264    feature(slice_index_methods, coerce_unsized, sgx_platform)
265)]
266#![cfg_attr(any(windows, target_os = "uefi"), feature(round_char_boundary))]
267#![cfg_attr(target_family = "wasm", feature(stdarch_wasm_atomic_wait))]
268#![cfg_attr(target_arch = "wasm64", feature(simd_wasm64))]
269//
270// Language features:
271// tidy-alphabetical-start
272
273// stabilization was reverted after it hit beta
274#![feature(alloc_error_handler)]
275#![feature(allocator_internals)]
276#![feature(allow_internal_unsafe)]
277#![feature(allow_internal_unstable)]
278#![feature(asm_experimental_arch)]
279#![feature(autodiff)]
280#![feature(cfg_sanitizer_cfi)]
281#![feature(cfg_target_thread_local)]
282#![feature(cfi_encoding)]
283#![feature(char_max_len)]
284#![feature(const_trait_impl)]
285#![feature(core_float_math)]
286#![feature(decl_macro)]
287#![feature(deprecated_suggestion)]
288#![feature(derive_const)]
289#![feature(doc_cfg)]
290#![feature(doc_cfg_hide)]
291#![feature(doc_masked)]
292#![feature(doc_notable_trait)]
293#![feature(dropck_eyepatch)]
294#![feature(extended_varargs_abi_support)]
295#![feature(f16)]
296#![feature(f128)]
297#![feature(ffi_const)]
298#![feature(formatting_options)]
299#![feature(hash_map_internals)]
300#![feature(hash_map_macro)]
301#![feature(if_let_guard)]
302#![feature(intra_doc_pointers)]
303#![feature(iter_advance_by)]
304#![feature(iter_next_chunk)]
305#![feature(lang_items)]
306#![feature(link_cfg)]
307#![feature(linkage)]
308#![feature(macro_metavar_expr_concat)]
309#![feature(maybe_uninit_fill)]
310#![feature(min_specialization)]
311#![feature(must_not_suspend)]
312#![feature(needs_panic_runtime)]
313#![feature(negative_impls)]
314#![feature(never_type)]
315#![feature(optimize_attribute)]
316#![feature(prelude_import)]
317#![feature(rustc_attrs)]
318#![feature(rustdoc_internals)]
319#![feature(staged_api)]
320#![feature(stmt_expr_attributes)]
321#![feature(strict_provenance_lints)]
322#![feature(thread_local)]
323#![feature(try_blocks)]
324#![feature(try_trait_v2)]
325#![feature(type_alias_impl_trait)]
326// tidy-alphabetical-end
327//
328// Library features (core):
329// tidy-alphabetical-start
330#![feature(bstr)]
331#![feature(bstr_internals)]
332#![feature(cast_maybe_uninit)]
333#![feature(cfg_select)]
334#![feature(char_internals)]
335#![feature(clone_to_uninit)]
336#![feature(const_cmp)]
337#![feature(const_ops)]
338#![feature(const_option_ops)]
339#![feature(const_try)]
340#![feature(core_intrinsics)]
341#![feature(core_io_borrowed_buf)]
342#![feature(drop_guard)]
343#![feature(duration_constants)]
344#![feature(error_generic_member_access)]
345#![feature(error_iter)]
346#![feature(exact_size_is_empty)]
347#![feature(exclusive_wrapper)]
348#![feature(extend_one)]
349#![feature(float_algebraic)]
350#![feature(float_gamma)]
351#![feature(float_minimum_maximum)]
352#![feature(fmt_internals)]
353#![feature(generic_atomic)]
354#![feature(hasher_prefixfree_extras)]
355#![feature(hashmap_internals)]
356#![feature(hint_must_use)]
357#![feature(ip)]
358#![feature(lazy_get)]
359#![feature(maybe_uninit_slice)]
360#![feature(maybe_uninit_write_slice)]
361#![feature(panic_can_unwind)]
362#![feature(panic_internals)]
363#![feature(pin_coerce_unsized_trait)]
364#![feature(pointer_is_aligned_to)]
365#![feature(portable_simd)]
366#![feature(ptr_as_uninit)]
367#![feature(ptr_mask)]
368#![feature(random)]
369#![feature(slice_internals)]
370#![feature(slice_ptr_get)]
371#![feature(slice_range)]
372#![feature(std_internals)]
373#![feature(str_internals)]
374#![feature(strict_provenance_atomic_ptr)]
375#![feature(sync_unsafe_cell)]
376#![feature(temporary_niche_types)]
377#![feature(ub_checks)]
378#![feature(used_with_arg)]
379// tidy-alphabetical-end
380//
381// Library features (alloc):
382// tidy-alphabetical-start
383#![feature(alloc_layout_extra)]
384#![feature(allocator_api)]
385#![feature(get_mut_unchecked)]
386#![feature(map_try_insert)]
387#![feature(new_zeroed_alloc)]
388#![feature(slice_concat_trait)]
389#![feature(thin_box)]
390#![feature(try_reserve_kind)]
391#![feature(try_with_capacity)]
392#![feature(unique_rc_arc)]
393#![feature(vec_into_raw_parts)]
394// tidy-alphabetical-end
395//
396// Library features (unwind):
397// tidy-alphabetical-start
398#![feature(panic_unwind)]
399// tidy-alphabetical-end
400//
401// Library features (std_detect):
402// tidy-alphabetical-start
403#![feature(stdarch_internal)]
404// tidy-alphabetical-end
405//
406// Only for re-exporting:
407// tidy-alphabetical-start
408#![feature(assert_matches)]
409#![feature(async_iterator)]
410#![feature(c_variadic)]
411#![feature(cfg_accessible)]
412#![feature(cfg_eval)]
413#![feature(concat_bytes)]
414#![feature(const_format_args)]
415#![feature(custom_test_frameworks)]
416#![feature(edition_panic)]
417#![feature(format_args_nl)]
418#![feature(log_syntax)]
419#![feature(test)]
420#![feature(trace_macros)]
421// tidy-alphabetical-end
422//
423// Only used in tests/benchmarks:
424//
425// Only for const-ness:
426// tidy-alphabetical-start
427#![feature(io_const_error)]
428// tidy-alphabetical-end
429//
430// Ferrocene added lints/features:
431#![feature(coverage_attribute)]
432//
433#![default_lib_allocator]
434
435// The Rust prelude
436// The compiler expects the prelude definition to be defined before it's use statement.
437pub mod prelude;
438
439// Explicitly import the prelude. The compiler uses this same unstable attribute
440// to import the prelude implicitly when building crates that depend on std.
441#[prelude_import]
442#[allow(unused)]
443use prelude::rust_2024::*;
444
445// Access to Bencher, etc.
446#[cfg(test)]
447extern crate test;
448
449#[allow(unused_imports)] // macros from `alloc` are not used on all platforms
450#[macro_use]
451extern crate alloc as alloc_crate;
452
453// Many compiler tests depend on libc being pulled in by std
454// so include it here even if it's unused.
455#[doc(masked)]
456#[allow(unused_extern_crates)]
457#[cfg(not(all(windows, target_env = "msvc")))]
458extern crate libc;
459
460// We always need an unwinder currently for backtraces
461#[doc(masked)]
462#[allow(unused_extern_crates)]
463extern crate unwind;
464
465// FIXME: #94122 this extern crate definition only exist here to stop
466// miniz_oxide docs leaking into std docs. Find better way to do it.
467// Remove exclusion from tidy platform check when this removed.
468#[doc(masked)]
469#[allow(unused_extern_crates)]
470#[cfg(all(
471    not(all(windows, target_env = "msvc", not(target_vendor = "uwp"))),
472    feature = "miniz_oxide"
473))]
474extern crate miniz_oxide;
475
476// During testing, this crate is not actually the "real" std library, but rather
477// it links to the real std library, which was compiled from this same source
478// code. So any lang items std defines are conditionally excluded (or else they
479// would generate duplicate lang item errors), and any globals it defines are
480// _not_ the globals used by "real" std. So this import, defined only during
481// testing gives test-std access to real-std lang items and globals. See #2912
482#[cfg(test)]
483extern crate std as realstd;
484
485// The standard macros that are not built-in to the compiler.
486#[macro_use]
487mod macros;
488
489// The runtime entry point and a few unstable public functions used by the
490// compiler
491#[macro_use]
492pub mod rt;
493
494#[stable(feature = "rust1", since = "1.0.0")]
495pub use core::any;
496#[stable(feature = "core_array", since = "1.35.0")]
497pub use core::array;
498#[unstable(feature = "async_iterator", issue = "79024")]
499pub use core::async_iter;
500#[stable(feature = "rust1", since = "1.0.0")]
501pub use core::cell;
502#[stable(feature = "rust1", since = "1.0.0")]
503pub use core::char;
504#[stable(feature = "rust1", since = "1.0.0")]
505pub use core::clone;
506#[stable(feature = "rust1", since = "1.0.0")]
507pub use core::cmp;
508#[stable(feature = "rust1", since = "1.0.0")]
509pub use core::convert;
510#[stable(feature = "rust1", since = "1.0.0")]
511pub use core::default;
512#[stable(feature = "futures_api", since = "1.36.0")]
513pub use core::future;
514#[stable(feature = "core_hint", since = "1.27.0")]
515pub use core::hint;
516#[stable(feature = "rust1", since = "1.0.0")]
517#[allow(deprecated, deprecated_in_future)]
518pub use core::i8;
519#[stable(feature = "rust1", since = "1.0.0")]
520#[allow(deprecated, deprecated_in_future)]
521pub use core::i16;
522#[stable(feature = "rust1", since = "1.0.0")]
523#[allow(deprecated, deprecated_in_future)]
524pub use core::i32;
525#[stable(feature = "rust1", since = "1.0.0")]
526#[allow(deprecated, deprecated_in_future)]
527pub use core::i64;
528#[stable(feature = "i128", since = "1.26.0")]
529#[allow(deprecated, deprecated_in_future)]
530pub use core::i128;
531#[stable(feature = "rust1", since = "1.0.0")]
532pub use core::intrinsics;
533#[stable(feature = "rust1", since = "1.0.0")]
534#[allow(deprecated, deprecated_in_future)]
535pub use core::isize;
536#[stable(feature = "rust1", since = "1.0.0")]
537pub use core::iter;
538#[stable(feature = "rust1", since = "1.0.0")]
539pub use core::marker;
540#[stable(feature = "rust1", since = "1.0.0")]
541pub use core::mem;
542#[stable(feature = "rust1", since = "1.0.0")]
543pub use core::ops;
544#[stable(feature = "rust1", since = "1.0.0")]
545pub use core::option;
546#[stable(feature = "pin", since = "1.33.0")]
547pub use core::pin;
548#[stable(feature = "rust1", since = "1.0.0")]
549pub use core::ptr;
550#[unstable(feature = "new_range_api", issue = "125687")]
551pub use core::range;
552#[stable(feature = "rust1", since = "1.0.0")]
553pub use core::result;
554#[stable(feature = "rust1", since = "1.0.0")]
555#[allow(deprecated, deprecated_in_future)]
556pub use core::u8;
557#[stable(feature = "rust1", since = "1.0.0")]
558#[allow(deprecated, deprecated_in_future)]
559pub use core::u16;
560#[stable(feature = "rust1", since = "1.0.0")]
561#[allow(deprecated, deprecated_in_future)]
562pub use core::u32;
563#[stable(feature = "rust1", since = "1.0.0")]
564#[allow(deprecated, deprecated_in_future)]
565pub use core::u64;
566#[stable(feature = "i128", since = "1.26.0")]
567#[allow(deprecated, deprecated_in_future)]
568pub use core::u128;
569#[unstable(feature = "unsafe_binders", issue = "130516")]
570pub use core::unsafe_binder;
571#[stable(feature = "rust1", since = "1.0.0")]
572#[allow(deprecated, deprecated_in_future)]
573pub use core::usize;
574
575#[stable(feature = "rust1", since = "1.0.0")]
576pub use alloc_crate::borrow;
577#[stable(feature = "rust1", since = "1.0.0")]
578pub use alloc_crate::boxed;
579#[stable(feature = "rust1", since = "1.0.0")]
580pub use alloc_crate::fmt;
581#[stable(feature = "rust1", since = "1.0.0")]
582pub use alloc_crate::format;
583#[stable(feature = "rust1", since = "1.0.0")]
584pub use alloc_crate::rc;
585#[stable(feature = "rust1", since = "1.0.0")]
586pub use alloc_crate::slice;
587#[stable(feature = "rust1", since = "1.0.0")]
588pub use alloc_crate::str;
589#[stable(feature = "rust1", since = "1.0.0")]
590pub use alloc_crate::string;
591#[stable(feature = "rust1", since = "1.0.0")]
592pub use alloc_crate::vec;
593
594#[path = "num/f128.rs"]
595pub mod f128;
596#[path = "num/f16.rs"]
597pub mod f16;
598#[path = "num/f32.rs"]
599pub mod f32;
600#[path = "num/f64.rs"]
601pub mod f64;
602
603#[macro_use]
604pub mod thread;
605pub mod ascii;
606pub mod backtrace;
607#[unstable(feature = "bstr", issue = "134915")]
608pub mod bstr;
609pub mod collections;
610pub mod env;
611pub mod error;
612pub mod ffi;
613pub mod fs;
614pub mod hash;
615pub mod io;
616pub mod net;
617pub mod num;
618pub mod os;
619pub mod panic;
620#[unstable(feature = "pattern_type_macro", issue = "123646")]
621pub mod pat;
622pub mod path;
623pub mod process;
624#[unstable(feature = "random", issue = "130703")]
625pub mod random;
626pub mod sync;
627pub mod time;
628
629// Pull in `std_float` crate  into std. The contents of
630// `std_float` are in a different repository: rust-lang/portable-simd.
631#[path = "../../portable-simd/crates/std_float/src/lib.rs"]
632#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
633#[allow(rustdoc::bare_urls)]
634#[unstable(feature = "portable_simd", issue = "86656")]
635mod std_float;
636
637#[unstable(feature = "portable_simd", issue = "86656")]
638pub mod simd {
639    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
640
641    #[doc(inline)]
642    pub use core::simd::*;
643
644    #[doc(inline)]
645    pub use crate::std_float::StdFloat;
646}
647
648#[unstable(feature = "autodiff", issue = "124509")]
649/// This module provides support for automatic differentiation.
650pub mod autodiff {
651    /// This macro handles automatic differentiation.
652    pub use core::autodiff::{autodiff_forward, autodiff_reverse};
653}
654
655#[stable(feature = "futures_api", since = "1.36.0")]
656pub mod task {
657    //! Types and Traits for working with asynchronous tasks.
658
659    #[doc(inline)]
660    #[stable(feature = "wake_trait", since = "1.51.0")]
661    pub use alloc::task::*;
662    #[doc(inline)]
663    #[stable(feature = "futures_api", since = "1.36.0")]
664    pub use core::task::*;
665}
666
667#[doc = include_str!("../../stdarch/crates/core_arch/src/core_arch_docs.md")]
668#[stable(feature = "simd_arch", since = "1.27.0")]
669pub mod arch {
670    #[stable(feature = "simd_arch", since = "1.27.0")]
671    // The `no_inline`-attribute is required to make the documentation of all
672    // targets available.
673    // See https://github.com/rust-lang/rust/pull/57808#issuecomment-457390549 for
674    // more information.
675    #[doc(no_inline)] // Note (#82861): required for correct documentation
676    pub use core::arch::*;
677
678    #[stable(feature = "simd_aarch64", since = "1.60.0")]
679    pub use std_detect::is_aarch64_feature_detected;
680    #[unstable(feature = "stdarch_arm_feature_detection", issue = "111190")]
681    pub use std_detect::is_arm_feature_detected;
682    #[unstable(feature = "is_loongarch_feature_detected", issue = "117425")]
683    pub use std_detect::is_loongarch_feature_detected;
684    #[unstable(feature = "is_riscv_feature_detected", issue = "111192")]
685    pub use std_detect::is_riscv_feature_detected;
686    #[unstable(feature = "stdarch_s390x_feature_detection", issue = "135413")]
687    pub use std_detect::is_s390x_feature_detected;
688    #[stable(feature = "simd_x86", since = "1.27.0")]
689    pub use std_detect::is_x86_feature_detected;
690    #[unstable(feature = "stdarch_mips_feature_detection", issue = "111188")]
691    pub use std_detect::{is_mips_feature_detected, is_mips64_feature_detected};
692    #[unstable(feature = "stdarch_powerpc_feature_detection", issue = "111191")]
693    pub use std_detect::{is_powerpc_feature_detected, is_powerpc64_feature_detected};
694}
695
696// This was stabilized in the crate root so we have to keep it there.
697#[stable(feature = "simd_x86", since = "1.27.0")]
698pub use std_detect::is_x86_feature_detected;
699
700// Platform-abstraction modules
701mod sys;
702mod sys_common;
703
704pub mod alloc;
705
706// Private support modules
707mod panicking;
708
709#[path = "../../../ferrocene/library/backtrace-rs/src/lib.rs"]
710#[allow(dead_code, unused_attributes, fuzzy_provenance_casts, unsafe_op_in_unsafe_fn)]
711mod backtrace_rs;
712
713#[unstable(feature = "cfg_select", issue = "115585")]
714pub use core::cfg_select;
715#[unstable(
716    feature = "concat_bytes",
717    issue = "87555",
718    reason = "`concat_bytes` is not stable enough for use and is subject to change"
719)]
720pub use core::concat_bytes;
721#[stable(feature = "matches_macro", since = "1.42.0")]
722#[allow(deprecated, deprecated_in_future)]
723pub use core::matches;
724#[stable(feature = "core_primitive", since = "1.43.0")]
725pub use core::primitive;
726#[stable(feature = "todo_macro", since = "1.40.0")]
727#[allow(deprecated, deprecated_in_future)]
728pub use core::todo;
729// Re-export built-in macros defined through core.
730#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
731pub use core::{
732    assert, assert_matches, cfg, column, compile_error, concat, const_format_args, env, file,
733    format_args, format_args_nl, include, include_bytes, include_str, line, log_syntax,
734    module_path, option_env, stringify, trace_macros,
735};
736// Re-export macros defined in core.
737#[stable(feature = "rust1", since = "1.0.0")]
738#[allow(deprecated, deprecated_in_future)]
739pub use core::{
740    assert_eq, assert_ne, debug_assert, debug_assert_eq, debug_assert_ne, r#try, unimplemented,
741    unreachable, write, writeln,
742};
743
744// Re-export unstable derive macro defined through core.
745#[unstable(feature = "derive_from", issue = "144889")]
746/// Unstable module containing the unstable `From` derive macro.
747pub mod from {
748    #[unstable(feature = "derive_from", issue = "144889")]
749    pub use core::from::From;
750}
751
752// Include a number of private modules that exist solely to provide
753// the rustdoc documentation for primitive types. Using `include!`
754// because rustdoc only looks for these modules at the crate level.
755include!("../../core/src/primitive_docs.rs");
756
757// Include a number of private modules that exist solely to provide
758// the rustdoc documentation for the existing keywords. Using `include!`
759// because rustdoc only looks for these modules at the crate level.
760include!("keyword_docs.rs");
761
762// This is required to avoid an unstable error when `restricted-std` is not
763// enabled. The use of #![feature(restricted_std)] in rustc-std-workspace-std
764// is unconditional, so the unstable feature needs to be defined somewhere.
765#[unstable(feature = "restricted_std", issue = "none")]
766mod __restricted_std_workaround {}
767
768mod sealed {
769    /// This trait being unreachable from outside the crate
770    /// prevents outside implementations of our extension traits.
771    /// This allows adding more trait methods in the future.
772    #[unstable(feature = "sealed", issue = "none")]
773    pub trait Sealed {}
774}
775
776#[cfg(test)]
777#[allow(dead_code)] // Not used in all configurations.
778pub(crate) mod test_helpers;