1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
//! # The Rust Standard Library
//!
//! The Rust Standard Library is the foundation of portable Rust software, a
//! set of minimal and battle-tested shared abstractions for the [broader Rust
//! ecosystem][crates.io]. It offers core types, like [`Vec<T>`] and
//! [`Option<T>`], library-defined [operations on language
//! primitives](#primitives), [standard macros](#macros), [I/O] and
//! [multithreading], among [many other things][other].
//!
//! `std` is available to all Rust crates by default. Therefore, the
//! standard library can be accessed in [`use`] statements through the path
//! `std`, as in [`use std::env`].
//!
//! # How to read this documentation
//!
//! If you already know the name of what you are looking for, the fastest way to
//! find it is to use the <a href="#" onclick="window.searchState.focus();">search
//! bar</a> at the top of the page.
//!
//! Otherwise, you may want to jump to one of these useful sections:
//!
//! * [`std::*` modules](#modules)
//! * [Primitive types](#primitives)
//! * [Standard macros](#macros)
//! * [The Rust Prelude]
//!
//! If this is your first time, the documentation for the standard library is
//! written to be casually perused. Clicking on interesting things should
//! generally lead you to interesting places. Still, there are important bits
//! you don't want to miss, so read on for a tour of the standard library and
//! its documentation!
//!
//! Once you are familiar with the contents of the standard library you may
//! begin to find the verbosity of the prose distracting. At this stage in your
//! development you may want to press the `[-]` button near the top of the
//! page to collapse it into a more skimmable view.
//!
//! While you are looking at that `[-]` button also notice the `source`
//! link. Rust's API documentation comes with the source code and you are
//! encouraged to read it. The standard library source is generally high
//! quality and a peek behind the curtains is often enlightening.
//!
//! # What is in the standard library documentation?
//!
//! First of all, The Rust Standard Library is divided into a number of focused
//! modules, [all listed further down this page](#modules). These modules are
//! the bedrock upon which all of Rust is forged, and they have mighty names
//! like [`std::slice`] and [`std::cmp`]. Modules' documentation typically
//! includes an overview of the module along with examples, and are a smart
//! place to start familiarizing yourself with the library.
//!
//! Second, implicit methods on [primitive types] are documented here. This can
//! be a source of confusion for two reasons:
//!
//! 1. While primitives are implemented by the compiler, the standard library
//!    implements methods directly on the primitive types (and it is the only
//!    library that does so), which are [documented in the section on
//!    primitives](#primitives).
//! 2. The standard library exports many modules *with the same name as
//!    primitive types*. These define additional items related to the primitive
//!    type, but not the all-important methods.
//!
//! So for example there is a [page for the primitive type
//! `i32`](primitive::i32) that lists all the methods that can be called on
//! 32-bit integers (very useful), and there is a [page for the module
//! `std::i32`] that documents the constant values [`MIN`] and [`MAX`] (rarely
//! useful).
//!
//! Note the documentation for the primitives [`str`] and [`[T]`][prim@slice] (also
//! called 'slice'). Many method calls on [`String`] and [`Vec<T>`] are actually
//! calls to methods on [`str`] and [`[T]`][prim@slice] respectively, via [deref
//! coercions][deref-coercions].
//!
//! Third, the standard library defines [The Rust Prelude], a small collection
//! of items - mostly traits - that are imported into every module of every
//! crate. The traits in the prelude are pervasive, making the prelude
//! documentation a good entry point to learning about the library.
//!
//! And finally, the standard library exports a number of standard macros, and
//! [lists them on this page](#macros) (technically, not all of the standard
//! macros are defined by the standard library - some are defined by the
//! compiler - but they are documented here the same). Like the prelude, the
//! standard macros are imported by default into all crates.
//!
//! # Contributing changes to the documentation
//!
//! Check out the rust contribution guidelines [here](
//! https://rustc-dev-guide.rust-lang.org/contributing.html#writing-documentation).
//! The source for this documentation can be found on
//! [GitHub](https://github.com/rust-lang/rust).
//! To contribute changes, make sure you read the guidelines first, then submit
//! pull-requests for your suggested changes.
//!
//! Contributions are appreciated! If you see a part of the docs that can be
//! improved, submit a PR, or chat with us first on [Discord][rust-discord]
//! #docs.
//!
//! # A Tour of The Rust Standard Library
//!
//! The rest of this crate documentation is dedicated to pointing out notable
//! features of The Rust Standard Library.
//!
//! ## Containers and collections
//!
//! The [`option`] and [`result`] modules define optional and error-handling
//! types, [`Option<T>`] and [`Result<T, E>`]. The [`iter`] module defines
//! Rust's iterator trait, [`Iterator`], which works with the [`for`] loop to
//! access collections.
//!
//! The standard library exposes three common ways to deal with contiguous
//! regions of memory:
//!
//! * [`Vec<T>`] - A heap-allocated *vector* that is resizable at runtime.
//! * [`[T; N]`][prim@array] - An inline *array* with a fixed size at compile time.
//! * [`[T]`][prim@slice] - A dynamically sized *slice* into any other kind of contiguous
//!   storage, whether heap-allocated or not.
//!
//! Slices can only be handled through some kind of *pointer*, and as such come
//! in many flavors such as:
//!
//! * `&[T]` - *shared slice*
//! * `&mut [T]` - *mutable slice*
//! * [`Box<[T]>`][owned slice] - *owned slice*
//!
//! [`str`], a UTF-8 string slice, is a primitive type, and the standard library
//! defines many methods for it. Rust [`str`]s are typically accessed as
//! immutable references: `&str`. Use the owned [`String`] for building and
//! mutating strings.
//!
//! For converting to strings use the [`format!`] macro, and for converting from
//! strings use the [`FromStr`] trait.
//!
//! Data may be shared by placing it in a reference-counted box or the [`Rc`]
//! type, and if further contained in a [`Cell`] or [`RefCell`], may be mutated
//! as well as shared. Likewise, in a concurrent setting it is common to pair an
//! atomically-reference-counted box, [`Arc`], with a [`Mutex`] to get the same
//! effect.
//!
//! The [`collections`] module defines maps, sets, linked lists and other
//! typical collection types, including the common [`HashMap<K, V>`].
//!
//! ## Platform abstractions and I/O
//!
//! Besides basic data types, the standard library is largely concerned with
//! abstracting over differences in common platforms, most notably Windows and
//! Unix derivatives.
//!
//! Common types of I/O, including [files], [TCP], and [UDP], are defined in
//! the [`io`], [`fs`], and [`net`] modules.
//!
//! The [`thread`] module contains Rust's threading abstractions. [`sync`]
//! contains further primitive shared memory types, including [`atomic`] and
//! [`mpsc`], which contains the channel types for message passing.
//!
//! # Use before and after `main()`
//!
//! Many parts of the standard library are expected to work before and after `main()`;
//! but this is not guaranteed or ensured by tests. It is recommended that you write your own tests
//! and run them on each platform you wish to support.
//! This means that use of `std` before/after main, especially of features that interact with the
//! OS or global state, is exempted from stability and portability guarantees and instead only
//! provided on a best-effort basis. Nevertheless bug reports are appreciated.
//!
//! On the other hand `core` and `alloc` are most likely to work in such environments with
//! the caveat that any hookable behavior such as panics, oom handling or allocators will also
//! depend on the compatibility of the hooks.
//!
//! Some features may also behave differently outside main, e.g. stdio could become unbuffered,
//! some panics might turn into aborts, backtraces might not get symbolicated or similar.
//!
//! Non-exhaustive list of known limitations:
//!
//! - after-main use of thread-locals, which also affects additional features:
//!   - [`thread::current()`]
//!   - [`thread::scope()`]
//!   - [`sync::mpsc`]
//! - before-main stdio file descriptors are not guaranteed to be open on unix platforms
//!
//!
//! [I/O]: io
//! [`MIN`]: i32::MIN
//! [`MAX`]: i32::MAX
//! [page for the module `std::i32`]: crate::i32
//! [TCP]: net::TcpStream
//! [The Rust Prelude]: prelude
//! [UDP]: net::UdpSocket
//! [`Arc`]: sync::Arc
//! [owned slice]: boxed
//! [`Cell`]: cell::Cell
//! [`FromStr`]: str::FromStr
//! [`HashMap<K, V>`]: collections::HashMap
//! [`Mutex`]: sync::Mutex
//! [`Option<T>`]: option::Option
//! [`Rc`]: rc::Rc
//! [`RefCell`]: cell::RefCell
//! [`Result<T, E>`]: result::Result
//! [`Vec<T>`]: vec::Vec
//! [`atomic`]: sync::atomic
//! [`for`]: ../book/ch03-05-control-flow.html#looping-through-a-collection-with-for
//! [`str`]: prim@str
//! [`mpsc`]: sync::mpsc
//! [`std::cmp`]: cmp
//! [`std::slice`]: mod@slice
//! [`use std::env`]: env/index.html
//! [`use`]: ../book/ch07-02-defining-modules-to-control-scope-and-privacy.html
//! [crates.io]: https://crates.io
//! [deref-coercions]: ../book/ch15-02-deref.html#implicit-deref-coercions-with-functions-and-methods
//! [files]: fs::File
//! [multithreading]: thread
//! [other]: #what-is-in-the-standard-library-documentation
//! [primitive types]: ../book/ch03-02-data-types.html
//! [rust-discord]: https://discord.gg/rust-lang
//! [array]: prim@array
//! [slice]: prim@slice
// To run std tests without x.py without ending up with two copies of std, Miri needs to be
// able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>.
// rustc itself never sets the feature, so this line has no effect there.
#![cfg(any(not(feature = "miri-test-libstd"), test, doctest))]
// miri-test-libstd also prefers to make std use the sysroot versions of the dependencies.
#![cfg_attr(feature = "miri-test-libstd", feature(rustc_private))]
//
#![cfg_attr(not(feature = "restricted-std"), stable(feature = "rust1", since = "1.0.0"))]
#![cfg_attr(feature = "restricted-std", unstable(feature = "restricted_std", issue = "none"))]
#![doc(
    html_playground_url = "https://play.rust-lang.org/",
    issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
    test(no_crate_inject, attr(deny(warnings))),
    test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
)]
#![doc(rust_logo)]
#![doc(cfg_hide(
    not(test),
    not(any(test, bootstrap)),
    no_global_oom_handling,
    not(no_global_oom_handling)
))]
// Don't link to std. We are std.
#![no_std]
// Tell the compiler to link to either panic_abort or panic_unwind
#![needs_panic_runtime]
//
// Lints:
#![warn(deprecated_in_future)]
#![warn(missing_docs)]
#![warn(missing_debug_implementations)]
#![allow(explicit_outlives_requirements)]
#![allow(unused_lifetimes)]
#![allow(internal_features)]
#![deny(rustc::existing_doc_keyword)]
#![deny(fuzzy_provenance_casts)]
#![allow(rustdoc::redundant_explicit_links)]
// Ensure that std can be linked against panic_abort despite compiled with `-C panic=unwind`
#![deny(ffi_unwind_calls)]
// std may use features in a platform-specific way
#![allow(unused_features)]
//
// Features:
#![cfg_attr(test, feature(internal_output_capture, print_internals, update_panic_count, rt))]
#![cfg_attr(
    all(target_vendor = "fortanix", target_env = "sgx"),
    feature(slice_index_methods, coerce_unsized, sgx_platform)
)]
#![cfg_attr(any(windows, target_os = "uefi"), feature(round_char_boundary))]
#![cfg_attr(target_os = "xous", feature(slice_ptr_len))]
//
// Language features:
// tidy-alphabetical-start
#![cfg_attr(not(bootstrap), feature(cfg_sanitizer_cfi))]
#![feature(alloc_error_handler)]
#![feature(allocator_internals)]
#![feature(allow_internal_unsafe)]
#![feature(allow_internal_unstable)]
#![feature(c_unwind)]
#![feature(cfg_target_thread_local)]
#![feature(cfi_encoding)]
#![feature(concat_idents)]
#![feature(const_mut_refs)]
#![feature(const_trait_impl)]
#![feature(decl_macro)]
#![feature(deprecated_suggestion)]
#![feature(doc_cfg)]
#![feature(doc_cfg_hide)]
#![feature(doc_masked)]
#![feature(doc_notable_trait)]
#![feature(dropck_eyepatch)]
#![feature(exhaustive_patterns)]
#![feature(if_let_guard)]
#![feature(intra_doc_pointers)]
#![feature(lang_items)]
#![feature(let_chains)]
#![feature(link_cfg)]
#![feature(linkage)]
#![feature(min_specialization)]
#![feature(must_not_suspend)]
#![feature(needs_panic_runtime)]
#![feature(negative_impls)]
#![feature(never_type)]
#![feature(no_sanitize)]
#![feature(platform_intrinsics)]
#![feature(prelude_import)]
#![feature(rustc_attrs)]
#![feature(rustdoc_internals)]
#![feature(staged_api)]
#![feature(thread_local)]
#![feature(try_blocks)]
#![feature(type_alias_impl_trait)]
#![feature(utf8_chunks)]
// tidy-alphabetical-end
//
// Library features (core):
// tidy-alphabetical-start
#![cfg_attr(bootstrap, feature(c_str_literals))]
#![feature(char_internals)]
#![feature(core_intrinsics)]
#![feature(core_io_borrowed_buf)]
#![feature(duration_constants)]
#![feature(error_generic_member_access)]
#![feature(error_in_core)]
#![feature(error_iter)]
#![feature(exact_size_is_empty)]
#![feature(exclusive_wrapper)]
#![feature(exposed_provenance)]
#![feature(extend_one)]
#![feature(float_gamma)]
#![feature(float_minimum_maximum)]
#![feature(float_next_up_down)]
#![feature(generic_nonzero)]
#![feature(hasher_prefixfree_extras)]
#![feature(hashmap_internals)]
#![feature(hint_assert_unchecked)]
#![feature(ip)]
#![feature(maybe_uninit_slice)]
#![feature(maybe_uninit_uninit_array)]
#![feature(maybe_uninit_write_slice)]
#![feature(panic_can_unwind)]
#![feature(panic_info_message)]
#![feature(panic_internals)]
#![feature(pointer_is_aligned)]
#![feature(portable_simd)]
#![feature(prelude_2024)]
#![feature(ptr_as_uninit)]
#![feature(slice_internals)]
#![feature(slice_ptr_get)]
#![feature(slice_range)]
#![feature(std_internals)]
#![feature(str_internals)]
#![feature(strict_provenance)]
// tidy-alphabetical-end
//
// Library features (alloc):
// tidy-alphabetical-start
#![feature(alloc_layout_extra)]
#![feature(allocator_api)]
#![feature(get_mut_unchecked)]
#![feature(map_try_insert)]
#![feature(new_uninit)]
#![feature(slice_concat_trait)]
#![feature(thin_box)]
#![feature(try_reserve_kind)]
#![feature(vec_into_raw_parts)]
// tidy-alphabetical-end
//
// Library features (unwind):
// tidy-alphabetical-start
#![feature(panic_unwind)]
// tidy-alphabetical-end
//
// Only for re-exporting:
// tidy-alphabetical-start
#![feature(assert_matches)]
#![feature(async_iterator)]
#![feature(c_variadic)]
#![feature(cfg_accessible)]
#![feature(cfg_eval)]
#![feature(concat_bytes)]
#![feature(const_format_args)]
#![feature(custom_test_frameworks)]
#![feature(edition_panic)]
#![feature(format_args_nl)]
#![feature(get_many_mut)]
#![feature(lazy_cell)]
#![feature(log_syntax)]
#![feature(stdsimd)]
#![feature(test)]
#![feature(trace_macros)]
// tidy-alphabetical-end
//
// Only used in tests/benchmarks:
//
// Only for const-ness:
// tidy-alphabetical-start
#![feature(const_collections_with_hasher)]
#![feature(const_hash)]
#![feature(const_io_structs)]
#![feature(const_ip)]
#![feature(const_ipv4)]
#![feature(const_ipv6)]
#![feature(const_maybe_uninit_uninit_array)]
#![feature(const_waker)]
#![feature(thread_local_internals)]
// tidy-alphabetical-end
//
#![default_lib_allocator]

// Explicitly import the prelude. The compiler uses this same unstable attribute
// to import the prelude implicitly when building crates that depend on std.
#[prelude_import]
#[allow(unused)]
use prelude::rust_2021::*;

// Access to Bencher, etc.
#[cfg(test)]
extern crate test;

#[allow(unused_imports)] // macros from `alloc` are not used on all platforms
#[macro_use]
extern crate alloc as alloc_crate;
#[doc(masked)]
#[allow(unused_extern_crates)]
extern crate libc;

// We always need an unwinder currently for backtraces
#[doc(masked)]
#[allow(unused_extern_crates)]
extern crate unwind;

// FIXME: #94122 this extern crate definition only exist here to stop
// miniz_oxide docs leaking into std docs. Find better way to do it.
// Remove exclusion from tidy platform check when this removed.
#[doc(masked)]
#[allow(unused_extern_crates)]
#[cfg(all(
    not(all(windows, target_env = "msvc", not(target_vendor = "uwp"))),
    feature = "miniz_oxide"
))]
extern crate miniz_oxide;

// During testing, this crate is not actually the "real" std library, but rather
// it links to the real std library, which was compiled from this same source
// code. So any lang items std defines are conditionally excluded (or else they
// would generate duplicate lang item errors), and any globals it defines are
// _not_ the globals used by "real" std. So this import, defined only during
// testing gives test-std access to real-std lang items and globals. See #2912
#[cfg(test)]
extern crate std as realstd;

// The standard macros that are not built-in to the compiler.
#[macro_use]
mod macros;

// The runtime entry point and a few unstable public functions used by the
// compiler
#[macro_use]
pub mod rt;

// The Rust prelude
pub mod prelude;

// Public module declarations and re-exports
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::borrow;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::boxed;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::fmt;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::format;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::rc;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::slice;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::str;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::string;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::vec;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::any;
#[stable(feature = "core_array", since = "1.36.0")]
pub use core::array;
#[unstable(feature = "async_iterator", issue = "79024")]
pub use core::async_iter;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::cell;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::char;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::clone;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::cmp;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::convert;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::default;
#[stable(feature = "futures_api", since = "1.36.0")]
pub use core::future;
#[stable(feature = "core_hint", since = "1.27.0")]
pub use core::hint;
#[stable(feature = "i128", since = "1.26.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::i128;
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::i16;
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::i32;
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::i64;
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::i8;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::intrinsics;
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::isize;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::iter;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::marker;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::mem;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::ops;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::option;
#[stable(feature = "pin", since = "1.33.0")]
pub use core::pin;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::ptr;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::result;
#[stable(feature = "i128", since = "1.26.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::u128;
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::u16;
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::u32;
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::u64;
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::u8;
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::usize;

pub mod f32;
pub mod f64;

#[macro_use]
pub mod thread;
pub mod ascii;
pub mod backtrace;
pub mod collections;
pub mod env;
pub mod error;
pub mod ffi;
pub mod fs;
pub mod hash;
pub mod io;
pub mod net;
pub mod num;
pub mod os;
pub mod panic;
pub mod path;
pub mod process;
pub mod sync;
pub mod time;

// Pull in `std_float` crate  into std. The contents of
// `std_float` are in a different repository: rust-lang/portable-simd.
#[path = "../../portable-simd/crates/std_float/src/lib.rs"]
#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
#[allow(rustdoc::bare_urls)]
#[unstable(feature = "portable_simd", issue = "86656")]
mod std_float;

#[unstable(feature = "portable_simd", issue = "86656")]
pub mod simd {
    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]

    #[doc(inline)]
    pub use crate::std_float::StdFloat;
    #[doc(inline)]
    pub use core::simd::*;
}

#[stable(feature = "futures_api", since = "1.36.0")]
pub mod task {
    //! Types and Traits for working with asynchronous tasks.

    #[doc(inline)]
    #[stable(feature = "futures_api", since = "1.36.0")]
    pub use core::task::*;

    #[doc(inline)]
    #[stable(feature = "wake_trait", since = "1.51.0")]
    pub use alloc::task::*;
}

#[doc = include_str!("../../stdarch/crates/core_arch/src/core_arch_docs.md")]
#[stable(feature = "simd_arch", since = "1.27.0")]
pub mod arch {
    #[stable(feature = "simd_arch", since = "1.27.0")]
    // The `no_inline`-attribute is required to make the documentation of all
    // targets available.
    // See https://github.com/rust-lang/rust/pull/57808#issuecomment-457390549 for
    // more information.
    #[doc(no_inline)] // Note (#82861): required for correct documentation
    pub use core::arch::*;

    #[stable(feature = "simd_aarch64", since = "1.60.0")]
    pub use std_detect::is_aarch64_feature_detected;
    #[stable(feature = "simd_x86", since = "1.27.0")]
    pub use std_detect::is_x86_feature_detected;
    #[unstable(feature = "stdsimd", issue = "48556")]
    pub use std_detect::{
        is_arm_feature_detected, is_mips64_feature_detected, is_mips_feature_detected,
        is_powerpc64_feature_detected, is_powerpc_feature_detected, is_riscv_feature_detected,
    };
}

// This was stabilized in the crate root so we have to keep it there.
#[stable(feature = "simd_x86", since = "1.27.0")]
pub use std_detect::is_x86_feature_detected;

// Platform-abstraction modules
mod sys;
mod sys_common;

pub mod alloc;

// Private support modules
mod panicking;

#[path = "../../backtrace/src/lib.rs"]
#[allow(dead_code, unused_attributes, fuzzy_provenance_casts)]
mod backtrace_rs;

// Re-export macros defined in core.
#[stable(feature = "rust1", since = "1.0.0")]
#[allow(deprecated, deprecated_in_future)]
pub use core::{
    assert_eq, assert_ne, debug_assert, debug_assert_eq, debug_assert_ne, matches, todo, r#try,
    unimplemented, unreachable, write, writeln,
};

// Re-export built-in macros defined through core.
#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
#[allow(deprecated)]
pub use core::{
    assert, assert_matches, cfg, column, compile_error, concat, concat_idents, const_format_args,
    env, file, format_args, format_args_nl, include, include_bytes, include_str, line, log_syntax,
    module_path, option_env, stringify, trace_macros,
};

#[unstable(
    feature = "concat_bytes",
    issue = "87555",
    reason = "`concat_bytes` is not stable enough for use and is subject to change"
)]
pub use core::concat_bytes;

#[unstable(feature = "cfg_match", issue = "115585")]
pub use core::cfg_match;

#[stable(feature = "core_primitive", since = "1.43.0")]
pub use core::primitive;

// Include a number of private modules that exist solely to provide
// the rustdoc documentation for primitive types. Using `include!`
// because rustdoc only looks for these modules at the crate level.
include!("../../core/src/primitive_docs.rs");

// Include a number of private modules that exist solely to provide
// the rustdoc documentation for the existing keywords. Using `include!`
// because rustdoc only looks for these modules at the crate level.
include!("keyword_docs.rs");

// This is required to avoid an unstable error when `restricted-std` is not
// enabled. The use of #![feature(restricted_std)] in rustc-std-workspace-std
// is unconditional, so the unstable feature needs to be defined somewhere.
#[unstable(feature = "restricted_std", issue = "none")]
mod __restricted_std_workaround {}

mod sealed {
    /// This trait being unreachable from outside the crate
    /// prevents outside implementations of our extension traits.
    /// This allows adding more trait methods in the future.
    #[unstable(feature = "sealed", issue = "none")]
    pub trait Sealed {}
}

#[cfg(test)]
#[allow(dead_code)] // Not used in all configurations.
pub(crate) mod test_helpers {
    /// Test-only replacement for `rand::thread_rng()`, which is unusable for
    /// us, as we want to allow running stdlib tests on tier-3 targets which may
    /// not have `getrandom` support.
    ///
    /// Does a bit of a song and dance to ensure that the seed is different on
    /// each call (as some tests sadly rely on this), but doesn't try that hard.
    ///
    /// This is duplicated in the `core`, `alloc` test suites (as well as
    /// `std`'s integration tests), but figuring out a mechanism to share these
    /// seems far more painful than copy-pasting a 7 line function a couple
    /// times, given that even under a perma-unstable feature, I don't think we
    /// want to expose types from `rand` from `std`.
    #[track_caller]
    pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
        use core::hash::{BuildHasher, Hash, Hasher};
        let mut hasher = crate::hash::RandomState::new().build_hasher();
        core::panic::Location::caller().hash(&mut hasher);
        let hc64 = hasher.finish();
        let seed_vec = hc64.to_le_bytes().into_iter().chain(0u8..8).collect::<Vec<u8>>();
        let seed: [u8; 16] = seed_vec.as_slice().try_into().unwrap();
        rand::SeedableRng::from_seed(seed)
    }
}