1//! # The Rust core allocation and collections library
2//!
3//! This library provides smart pointers and collections for managing
4//! heap-allocated values.
5//!
6//! This library, like core, normally doesn’t need to be used directly
7//! since its contents are re-exported in the [`std` crate](../std/index.html).
8//! Crates that use the `#![no_std]` attribute however will typically
9//! not depend on `std`, so they’d use this crate instead.
10//!
11//! ## Boxed values
12//!
13//! The [`Box`] type is a smart pointer type. There can only be one owner of a
14//! [`Box`], and the owner can decide to mutate the contents, which live on the
15//! heap.
16//!
17//! This type can be sent among threads efficiently as the size of a `Box` value
18//! is the same as that of a pointer. Tree-like data structures are often built
19//! with boxes because each node often has only one owner, the parent.
20//!
21//! ## Reference counted pointers
22//!
23//! The [`Rc`] type is a non-threadsafe reference-counted pointer type intended
24//! for sharing memory within a thread. An [`Rc`] pointer wraps a type, `T`, and
25//! only allows access to `&T`, a shared reference.
26//!
27//! This type is useful when inherited mutability (such as using [`Box`]) is too
28//! constraining for an application, and is often paired with the [`Cell`] or
29//! [`RefCell`] types in order to allow mutation.
30//!
31//! ## Atomically reference counted pointers
32//!
33//! The [`Arc`] type is the threadsafe equivalent of the [`Rc`] type. It
34//! provides all the same functionality of [`Rc`], except it requires that the
35//! contained type `T` is shareable. Additionally, [`Arc<T>`][`Arc`] is itself
36//! sendable while [`Rc<T>`][`Rc`] is not.
37//!
38//! This type allows for shared access to the contained data, and is often
39//! paired with synchronization primitives such as mutexes to allow mutation of
40//! shared resources.
41//!
42//! ## Collections
43//!
44//! Implementations of the most common general purpose data structures are
45//! defined in this library. They are re-exported through the
46//! [standard collections library](../std/collections/index.html).
47//!
48//! ## Heap interfaces
49//!
50//! The [`alloc`](alloc/index.html) module defines the low-level interface to the
51//! default global allocator. It is not compatible with the libc allocator API.
52//!
53//! [`Arc`]: sync
54//! [`Box`]: boxed
55//! [`Cell`]: core::cell
56//! [`Rc`]: rc
57//! [`RefCell`]: core::cell
58
59#![allow(incomplete_features)]
60#![allow(unused_attributes)]
61#![stable(feature = "alloc", since = "1.36.0")]
62#![doc(
63 html_playground_url = "https://play.rust-lang.org/",
64 issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
65 test(no_crate_inject, attr(allow(unused_variables), deny(warnings)))
66)]
67#![doc(cfg_hide(
68 not(test),
69 no_global_oom_handling,
70 not(no_global_oom_handling),
71 not(no_rc),
72 not(no_sync),
73 target_has_atomic = "ptr"
74))]
75#![doc(rust_logo)]
76#![feature(rustdoc_internals)]
77#![no_std]
78#![needs_allocator]
79// Lints:
80#![deny(unsafe_op_in_unsafe_fn)]
81#![deny(fuzzy_provenance_casts)]
82#![warn(deprecated_in_future)]
83#![warn(missing_debug_implementations)]
84#![warn(missing_docs)]
85#![allow(explicit_outlives_requirements)]
86#![warn(multiple_supertrait_upcastable)]
87#![allow(internal_features)]
88#![allow(rustdoc::redundant_explicit_links)]
89#![warn(rustdoc::unescaped_backticks)]
90#![deny(ffi_unwind_calls)]
91#![warn(unreachable_pub)]
92//
93// Library features:
94// tidy-alphabetical-start
95#![feature(alloc_layout_extra)]
96#![feature(allocator_api)]
97#![feature(array_chunks)]
98#![feature(array_into_iter_constructors)]
99#![feature(array_windows)]
100#![feature(ascii_char)]
101#![feature(assert_matches)]
102#![feature(async_fn_traits)]
103#![feature(async_iterator)]
104#![feature(bstr)]
105#![feature(bstr_internals)]
106#![feature(char_internals)]
107#![feature(char_max_len)]
108#![feature(clone_to_uninit)]
109#![feature(coerce_unsized)]
110#![feature(const_eval_select)]
111#![feature(const_heap)]
112#![feature(core_intrinsics)]
113#![feature(deprecated_suggestion)]
114#![feature(deref_pure_trait)]
115#![feature(dispatch_from_dyn)]
116#![feature(ergonomic_clones)]
117#![feature(error_generic_member_access)]
118#![feature(exact_size_is_empty)]
119#![feature(extend_one)]
120#![feature(extend_one_unchecked)]
121#![feature(fmt_internals)]
122#![feature(fn_traits)]
123#![feature(formatting_options)]
124#![feature(generic_atomic)]
125#![feature(hasher_prefixfree_extras)]
126#![feature(inplace_iteration)]
127#![feature(iter_advance_by)]
128#![feature(iter_next_chunk)]
129#![feature(layout_for_ptr)]
130#![feature(legacy_receiver_trait)]
131#![feature(local_waker)]
132#![feature(maybe_uninit_slice)]
133#![feature(maybe_uninit_uninit_array_transpose)]
134#![feature(panic_internals)]
135#![feature(pattern)]
136#![feature(pin_coerce_unsized_trait)]
137#![feature(pointer_like_trait)]
138#![feature(ptr_alignment_type)]
139#![feature(ptr_internals)]
140#![feature(ptr_metadata)]
141#![feature(set_ptr_value)]
142#![feature(sized_type_properties)]
143#![feature(slice_from_ptr_range)]
144#![feature(slice_index_methods)]
145#![feature(slice_iter_mut_as_mut_slice)]
146#![feature(slice_ptr_get)]
147#![feature(slice_range)]
148#![feature(std_internals)]
149#![feature(str_internals)]
150#![feature(temporary_niche_types)]
151#![feature(trusted_fused)]
152#![feature(trusted_len)]
153#![feature(trusted_random_access)]
154#![feature(try_trait_v2)]
155#![feature(try_with_capacity)]
156#![feature(tuple_trait)]
157#![feature(unicode_internals)]
158#![feature(unsize)]
159#![feature(unwrap_infallible)]
160// tidy-alphabetical-end
161//
162// Language features:
163// tidy-alphabetical-start
164#![feature(allocator_internals)]
165#![feature(allow_internal_unstable)]
166#![feature(cfg_sanitize)]
167#![feature(const_precise_live_drops)]
168#![feature(coroutine_trait)]
169#![feature(decl_macro)]
170#![feature(dropck_eyepatch)]
171#![feature(fundamental)]
172#![feature(hashmap_internals)]
173#![feature(intrinsics)]
174#![feature(lang_items)]
175#![feature(min_specialization)]
176#![feature(multiple_supertrait_upcastable)]
177#![feature(negative_impls)]
178#![feature(never_type)]
179#![feature(optimize_attribute)]
180#![feature(rustc_allow_const_fn_unstable)]
181#![feature(rustc_attrs)]
182#![feature(slice_internals)]
183#![feature(staged_api)]
184#![feature(stmt_expr_attributes)]
185#![feature(strict_provenance_lints)]
186#![feature(unboxed_closures)]
187#![feature(unsized_fn_params)]
188#![feature(with_negative_coherence)]
189#![rustc_preserve_ub_checks]
190// tidy-alphabetical-end
191//
192// Rustdoc features:
193#![feature(doc_cfg)]
194#![feature(doc_cfg_hide)]
195// Technically, this is a bug in rustdoc: rustdoc sees the documentation on `#[lang = slice_alloc]`
196// blocks is for `&[T]`, which also has documentation using this feature in `core`, and gets mad
197// that the feature-gate isn't enabled. Ideally, it wouldn't check for the feature gate for docs
198// from other crates, but since this can only appear for lang items, it doesn't seem worth fixing.
199#![feature(intra_doc_pointers)]
200
201// Module with internal macros used by other modules (needs to be included before other modules).
202#[macro_use]
203mod macros;
204
205mod raw_vec;
206
207// Heaps provided for low-level allocation strategies
208pub mod alloc;
209
210// Primitive types using the heaps above
211
212// Need to conditionally define the mod from `boxed.rs` to avoid
213// duplicating the lang-items when building in test cfg; but also need
214// to allow code to have `use boxed::Box;` declarations.
215pub mod borrow;
216pub mod boxed;
217#[unstable(feature = "bstr", issue = "134915")]
218pub mod bstr;
219pub mod collections;
220#[cfg(all(not(no_rc), not(no_sync), not(no_global_oom_handling)))]
221pub mod ffi;
222pub mod fmt;
223#[cfg(not(no_rc))]
224pub mod rc;
225pub mod slice;
226pub mod str;
227pub mod string;
228#[cfg(all(not(no_rc), not(no_sync), target_has_atomic = "ptr"))]
229pub mod sync;
230#[cfg(all(not(no_global_oom_handling), not(no_rc), not(no_sync)))]
231pub mod task;
232pub mod vec;
233
234#[doc(hidden)]
235#[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]
236pub mod __export {
237 pub use core::format_args;
238 pub use core::hint::must_use;
239}
240