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Created: 2026-05-16 07:02

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/rust/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.52.3/src/lib.rs
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1
#![allow(
2
    clippy::cognitive_complexity,
3
    clippy::large_enum_variant,
4
    clippy::module_inception,
5
    clippy::needless_doctest_main
6
)]
7
#![warn(
8
    missing_debug_implementations,
9
    missing_docs,
10
    rust_2018_idioms,
11
    unreachable_pub
12
)]
13
#![deny(unused_must_use, unsafe_op_in_unsafe_fn)]
14
#![doc(test(
15
    no_crate_inject,
16
    attr(deny(warnings, rust_2018_idioms), allow(dead_code, unused_variables))
17
))]
18
// loom is an internal implementation detail.
19
// Do not show "Available on non-loom only" label
20
#![cfg_attr(docsrs, doc(auto_cfg(hide(loom))))]
21
#![cfg_attr(docsrs, feature(doc_cfg))]
22
#![cfg_attr(docsrs, allow(unused_attributes))]
23
#![cfg_attr(loom, allow(dead_code, unreachable_pub))]
24
#![cfg_attr(windows, allow(rustdoc::broken_intra_doc_links))]
25
26
//! A runtime for writing reliable network applications without compromising speed.
27
//!
28
//! Tokio is an event-driven, non-blocking I/O platform for writing asynchronous
29
//! applications with the Rust programming language. At a high level, it
30
//! provides a few major components:
31
//!
32
//! * Tools for [working with asynchronous tasks][tasks], including
33
//!   [synchronization primitives and channels][sync] and [timeouts, sleeps, and
34
//!   intervals][time].
35
//! * APIs for [performing asynchronous I/O][io], including [TCP and UDP][net] sockets,
36
//!   [filesystem][fs] operations, and [process] and [signal] management.
37
//! * A [runtime] for executing asynchronous code, including a task scheduler,
38
//!   an I/O driver backed by the operating system's event queue (`epoll`, `kqueue`,
39
//!   `IOCP`, etc...), and a high performance timer.
40
//!
41
//! Guide level documentation is found on the [website].
42
//!
43
//! [tasks]: #working-with-tasks
44
//! [sync]: crate::sync
45
//! [time]: crate::time
46
//! [io]: #asynchronous-io
47
//! [net]: crate::net
48
//! [fs]: crate::fs
49
//! [process]: crate::process
50
//! [signal]: crate::signal
51
//! [fs]: crate::fs
52
//! [runtime]: crate::runtime
53
//! [website]: https://tokio.rs/tokio/tutorial
54
//!
55
//! # A Tour of Tokio
56
//!
57
//! Tokio consists of a number of modules that provide a range of functionality
58
//! essential for implementing asynchronous applications in Rust. In this
59
//! section, we will take a brief tour of Tokio, summarizing the major APIs and
60
//! their uses.
61
//!
62
//! The easiest way to get started is to enable all features. Do this by
63
//! enabling the `full` feature flag:
64
//!
65
//! ```toml
66
//! tokio = { version = "1", features = ["full"] }
67
//! ```
68
//!
69
//! ### Authoring applications
70
//!
71
//! Tokio is great for writing applications and most users in this case shouldn't
72
//! worry too much about what features they should pick. If you're unsure, we suggest
73
//! going with `full` to ensure that you don't run into any road blocks while you're
74
//! building your application.
75
//!
76
//! #### Example
77
//!
78
//! This example shows the quickest way to get started with Tokio.
79
//!
80
//! ```toml
81
//! tokio = { version = "1", features = ["full"] }
82
//! ```
83
//!
84
//! ### Authoring libraries
85
//!
86
//! As a library author your goal should be to provide the lightest weight crate
87
//! that is based on Tokio. To achieve this you should ensure that you only enable
88
//! the features you need. This allows users to pick up your crate without having
89
//! to enable unnecessary features.
90
//!
91
//! #### Example
92
//!
93
//! This example shows how you may want to import features for a library that just
94
//! needs to `tokio::spawn` and use a `TcpStream`.
95
//!
96
//! ```toml
97
//! tokio = { version = "1", features = ["rt", "net"] }
98
//! ```
99
//!
100
//! ## Working With Tasks
101
//!
102
//! Asynchronous programs in Rust are based around lightweight, non-blocking
103
//! units of execution called [_tasks_][tasks]. The [`tokio::task`] module provides
104
//! important tools for working with tasks:
105
//!
106
//! * The [`spawn`] function and [`JoinHandle`] type, for scheduling a new task
107
//!   on the Tokio runtime and awaiting the output of a spawned task, respectively,
108
//! * Functions for [running blocking operations][blocking] in an asynchronous
109
//!   task context.
110
//!
111
//! The [`tokio::task`] module is present only when the "rt" feature flag
112
//! is enabled.
113
//!
114
//! [tasks]: task/index.html#what-are-tasks
115
//! [`tokio::task`]: crate::task
116
//! [`spawn`]: crate::task::spawn()
117
//! [`JoinHandle`]: crate::task::JoinHandle
118
//! [blocking]: task/index.html#blocking-and-yielding
119
//!
120
//! The [`tokio::sync`] module contains synchronization primitives to use when
121
//! needing to communicate or share data. These include:
122
//!
123
//! * channels ([`oneshot`], [`mpsc`], [`watch`], and [`broadcast`]), for sending values
124
//!   between tasks,
125
//! * a non-blocking [`Mutex`], for controlling access to a shared, mutable
126
//!   value,
127
//! * an asynchronous [`Barrier`] type, for multiple tasks to synchronize before
128
//!   beginning a computation.
129
//!
130
//! The `tokio::sync` module is present only when the "sync" feature flag is
131
//! enabled.
132
//!
133
//! [`tokio::sync`]: crate::sync
134
//! [`Mutex`]: crate::sync::Mutex
135
//! [`Barrier`]: crate::sync::Barrier
136
//! [`oneshot`]: crate::sync::oneshot
137
//! [`mpsc`]: crate::sync::mpsc
138
//! [`watch`]: crate::sync::watch
139
//! [`broadcast`]: crate::sync::broadcast
140
//!
141
//! The [`tokio::time`] module provides utilities for tracking time and
142
//! scheduling work. This includes functions for setting [timeouts][timeout] for
143
//! tasks, [sleeping][sleep] work to run in the future, or [repeating an operation at an
144
//! interval][interval].
145
//!
146
//! In order to use `tokio::time`, the "time" feature flag must be enabled.
147
//!
148
//! [`tokio::time`]: crate::time
149
//! [sleep]: crate::time::sleep()
150
//! [interval]: crate::time::interval()
151
//! [timeout]: crate::time::timeout()
152
//!
153
//! Finally, Tokio provides a _runtime_ for executing asynchronous tasks. Most
154
//! applications can use the [`#[tokio::main]`][main] macro to run their code on the
155
//! Tokio runtime. However, this macro provides only basic configuration options. As
156
//! an alternative, the [`tokio::runtime`] module provides more powerful APIs for configuring
157
//! and managing runtimes. You should use that module if the `#[tokio::main]` macro doesn't
158
//! provide the functionality you need.
159
//!
160
//! Using the runtime requires the "rt" or "rt-multi-thread" feature flags, to
161
//! enable the current-thread [single-threaded scheduler][rt] and the [multi-thread
162
//! scheduler][rt-multi-thread], respectively. See the [`runtime` module
163
//! documentation][rt-features] for details. In addition, the "macros" feature
164
//! flag enables the `#[tokio::main]` and `#[tokio::test]` attributes.
165
//!
166
//! [main]: attr.main.html
167
//! [`tokio::runtime`]: crate::runtime
168
//! [`Builder`]: crate::runtime::Builder
169
//! [`Runtime`]: crate::runtime::Runtime
170
//! [rt]: runtime/index.html#current-thread-scheduler
171
//! [rt-multi-thread]: runtime/index.html#multi-thread-scheduler
172
//! [rt-features]: runtime/index.html#runtime-scheduler
173
//!
174
//! ## CPU-bound tasks and blocking code
175
//!
176
//! Tokio is able to concurrently run many tasks on a few threads by repeatedly
177
//! swapping the currently running task on each thread. However, this kind of
178
//! swapping can only happen at `.await` points, so code that spends a long time
179
//! without reaching an `.await` will prevent other tasks from running. To
180
//! combat this, Tokio provides two kinds of threads: Core threads and blocking threads.
181
//!
182
//! The core threads are where all asynchronous code runs, and Tokio will by default
183
//! spawn one for each CPU core. You can use the environment variable `TOKIO_WORKER_THREADS`
184
//! to override the default value.
185
//!
186
//! The blocking threads are spawned on demand, can be used to run blocking code
187
//! that would otherwise block other tasks from running and are kept alive when
188
//! not used for a certain amount of time which can be configured with [`thread_keep_alive`].
189
//! Since it is not possible for Tokio to swap out blocking tasks, like it
190
//! can do with asynchronous code, the upper limit on the number of blocking
191
//! threads is very large. These limits can be configured on the [`Builder`].
192
//!
193
//! To spawn a blocking task, you should use the [`spawn_blocking`] function.
194
//!
195
//! [`Builder`]: crate::runtime::Builder
196
//! [`spawn_blocking`]: crate::task::spawn_blocking()
197
//! [`thread_keep_alive`]: crate::runtime::Builder::thread_keep_alive()
198
//!
199
//! ```
200
//! # #[cfg(not(target_family = "wasm"))]
201
//! # {
202
//! #[tokio::main]
203
//! async fn main() {
204
//!     // This is running on a core thread.
205
//!
206
//!     let blocking_task = tokio::task::spawn_blocking(|| {
207
//!         // This is running on a blocking thread.
208
//!         // Blocking here is ok.
209
//!     });
210
//!
211
//!     // We can wait for the blocking task like this:
212
//!     // If the blocking task panics, the unwrap below will propagate the
213
//!     // panic.
214
//!     blocking_task.await.unwrap();
215
//! }
216
//! # }
217
//! ```
218
//!
219
//! If your code is CPU-bound and you wish to limit the number of threads used
220
//! to run it, you should use a separate thread pool dedicated to CPU bound tasks.
221
//! For example, you could consider using the [rayon] library for CPU-bound
222
//! tasks. It is also possible to create an extra Tokio runtime dedicated to
223
//! CPU-bound tasks, but if you do this, you should be careful that the extra
224
//! runtime runs _only_ CPU-bound tasks, as IO-bound tasks on that runtime
225
//! will behave poorly.
226
//!
227
//! Hint: If using rayon, you can use a [`oneshot`] channel to send the result back
228
//! to Tokio when the rayon task finishes.
229
//!
230
//! [rayon]: https://docs.rs/rayon
231
//! [`oneshot`]: crate::sync::oneshot
232
//!
233
//! ## Asynchronous IO
234
//!
235
//! As well as scheduling and running tasks, Tokio provides everything you need
236
//! to perform input and output asynchronously.
237
//!
238
//! The [`tokio::io`] module provides Tokio's asynchronous core I/O primitives,
239
//! the [`AsyncRead`], [`AsyncWrite`], and [`AsyncBufRead`] traits. In addition,
240
//! when the "io-util" feature flag is enabled, it also provides combinators and
241
//! functions for working with these traits, forming as an asynchronous
242
//! counterpart to [`std::io`].
243
//!
244
//! Tokio also includes APIs for performing various kinds of I/O and interacting
245
//! with the operating system asynchronously. These include:
246
//!
247
//! * [`tokio::net`], which contains non-blocking versions of [TCP], [UDP], and
248
//!   [Unix Domain Sockets][UDS] (enabled by the "net" feature flag),
249
//! * [`tokio::fs`], similar to [`std::fs`] but for performing filesystem I/O
250
//!   asynchronously (enabled by the "fs" feature flag),
251
//! * [`tokio::signal`], for asynchronously handling Unix and Windows OS signals
252
//!   (enabled by the "signal" feature flag),
253
//! * [`tokio::process`], for spawning and managing child processes (enabled by
254
//!   the "process" feature flag).
255
//!
256
//! [`tokio::io`]: crate::io
257
//! [`AsyncRead`]: crate::io::AsyncRead
258
//! [`AsyncWrite`]: crate::io::AsyncWrite
259
//! [`AsyncBufRead`]: crate::io::AsyncBufRead
260
//! [`std::io`]: std::io
261
//! [`tokio::net`]: crate::net
262
//! [TCP]: crate::net::tcp
263
//! [UDP]: crate::net::UdpSocket
264
//! [UDS]: crate::net::unix
265
//! [`tokio::fs`]: crate::fs
266
//! [`std::fs`]: std::fs
267
//! [`tokio::signal`]: crate::signal
268
//! [`tokio::process`]: crate::process
269
//!
270
//! # Examples
271
//!
272
//! A simple TCP echo server:
273
//!
274
//! ```no_run
275
//! # #[cfg(not(target_family = "wasm"))]
276
//! # {
277
//! use tokio::net::TcpListener;
278
//! use tokio::io::{AsyncReadExt, AsyncWriteExt};
279
//!
280
//! #[tokio::main]
281
//! async fn main() -> Result<(), Box<dyn std::error::Error>> {
282
//!     let listener = TcpListener::bind("127.0.0.1:8080").await?;
283
//!
284
//!     loop {
285
//!         let (mut socket, _) = listener.accept().await?;
286
//!
287
//!         tokio::spawn(async move {
288
//!             let mut buf = [0; 1024];
289
//!
290
//!             // In a loop, read data from the socket and write the data back.
291
//!             loop {
292
//!                 let n = match socket.read(&mut buf).await {
293
//!                     // socket closed
294
//!                     Ok(0) => return,
295
//!                     Ok(n) => n,
296
//!                     Err(e) => {
297
//!                         eprintln!("failed to read from socket; err = {:?}", e);
298
//!                         return;
299
//!                     }
300
//!                 };
301
//!
302
//!                 // Write the data back
303
//!                 if let Err(e) = socket.write_all(&buf[0..n]).await {
304
//!                     eprintln!("failed to write to socket; err = {:?}", e);
305
//!                     return;
306
//!                 }
307
//!             }
308
//!         });
309
//!     }
310
//! }
311
//! # }
312
//! ```
313
//!
314
//! # Feature flags
315
//!
316
//! Tokio uses a set of [feature flags] to reduce the amount of compiled code. It
317
//! is possible to just enable certain features over others. By default, Tokio
318
//! does not enable any features but allows one to enable a subset for their use
319
//! case. Below is a list of the available feature flags. You may also notice
320
//! above each function, struct and trait there is listed one or more feature flags
321
//! that are required for that item to be used. If you are new to Tokio it is
322
//! recommended that you use the `full` feature flag which will enable all public APIs.
323
//! Beware though that this will pull in many extra dependencies that you may not
324
//! need.
325
//!
326
//! - `full`: Enables all features listed below except `test-util` and unstable features.
327
//! - `rt`: Enables `tokio::spawn`, the current-thread scheduler,
328
//!   and non-scheduler utilities.
329
//! - `rt-multi-thread`: Enables the heavier, multi-threaded, work-stealing scheduler.
330
//! - `io-util`: Enables the IO based `Ext` traits.
331
//! - `io-std`: Enable `Stdout`, `Stdin` and `Stderr` types.
332
//! - `net`: Enables `tokio::net` types such as `TcpStream`, `UnixStream` and
333
//!   `UdpSocket`, as well as (on Unix-like systems) `AsyncFd` and (on
334
//!   FreeBSD) `PollAio`.
335
//! - `time`: Enables `tokio::time` types and allows the schedulers to enable
336
//!   the built-in timer.
337
//! - `process`: Enables `tokio::process` types.
338
//! - `macros`: Enables `#[tokio::main]` and `#[tokio::test]` macros.
339
//! - `sync`: Enables all `tokio::sync` types.
340
//! - `signal`: Enables all `tokio::signal` types.
341
//! - `fs`: Enables `tokio::fs` types.
342
//! - `test-util`: Enables testing based infrastructure for the Tokio runtime.
343
//! - `parking_lot`: As a potential optimization, use the [`parking_lot`] crate's
344
//!   synchronization primitives internally. Also, this
345
//!   dependency is necessary to construct some of our primitives
346
//!   in a `const` context. `MSRV` may increase according to the
347
//!   [`parking_lot`] release in use.
348
//!
349
//! _Note: `AsyncRead` and `AsyncWrite` traits do not require any features and are
350
//! always available._
351
//!
352
//! ## Unstable features
353
//!
354
//! Some feature flags are only available when specifying the `tokio_unstable` flag:
355
//!
356
//! - `tracing`: Enables tracing events.
357
//! - `io-uring`: Enables `io-uring` (Linux only).
358
//! - `taskdump`: Enables `taskdump` (Linux only).
359
//!
360
//! Likewise, this flag enables access to unstable APIs.
361
//!
362
//! This flag enables **unstable** features. The public API of these features
363
//! may break in 1.x releases. To enable these features, the `--cfg
364
//! tokio_unstable` argument must be passed to `rustc` when compiling. This
365
//! serves to explicitly opt-in to features which may break semver conventions,
366
//! since Cargo [does not yet directly support such opt-ins][unstable features].
367
//!
368
//! You can specify it in your project's `.cargo/config.toml` file:
369
//!
370
//! ```toml
371
//! [build]
372
//! rustflags = ["--cfg", "tokio_unstable"]
373
//! ```
374
//!
375
//! <div class="warning">
376
//! The <code>[build]</code> section does <strong>not</strong> go in a
377
//! <code>Cargo.toml</code> file. Instead it must be placed in the Cargo config
378
//! file <code>.cargo/config.toml</code>.
379
//! </div>
380
//!
381
//! Alternatively, you can specify it with an environment variable:
382
//!
383
//! ```sh
384
//! ## Many *nix shells:
385
//! export RUSTFLAGS="--cfg tokio_unstable"
386
//! cargo build
387
//! ```
388
//!
389
//! ```powershell
390
//! ## Windows PowerShell:
391
//! $Env:RUSTFLAGS="--cfg tokio_unstable"
392
//! cargo build
393
//! ```
394
//!
395
//! [unstable features]: https://internals.rust-lang.org/t/feature-request-unstable-opt-in-non-transitive-crate-features/16193#why-not-a-crate-feature-2
396
//! [feature flags]: https://doc.rust-lang.org/cargo/reference/manifest.html#the-features-section
397
//!
398
//! # Supported platforms
399
//!
400
//! Tokio currently guarantees support for the following platforms:
401
//!
402
//!  * Linux
403
//!  * Windows
404
//!  * Android (API level 21)
405
//!  * macOS
406
//!  * iOS
407
//!  * FreeBSD
408
//!
409
//! Tokio will continue to support these platforms in the future. However,
410
//! future releases may change requirements such as the minimum required libc
411
//! version on Linux, the API level on Android, or the supported FreeBSD
412
//! release.
413
//!
414
//! Beyond the above platforms, Tokio is intended to work on all platforms
415
//! supported by the mio crate. You can find a longer list [in mio's
416
//! documentation][mio-supported]. However, these additional platforms may
417
//! become unsupported in the future.
418
//!
419
//! Note that Wine is considered to be a different platform from Windows. See
420
//! mio's documentation for more information on Wine support.
421
//!
422
//! [mio-supported]: https://crates.io/crates/mio#platforms
423
//!
424
//! ## `WASM` support
425
//!
426
//! Tokio has some limited support for the `WASM` platform. Without the
427
//! `tokio_unstable` flag, the following features are supported:
428
//!
429
//!  * `sync`
430
//!  * `macros`
431
//!  * `io-util`
432
//!  * `rt`
433
//!  * `time`
434
//!
435
//! Enabling any other feature (including `full`) will cause a compilation
436
//! failure.
437
//!
438
//! The `time` module will only work on `WASM` platforms that have support for
439
//! timers (e.g. wasm32-wasi). The timing functions will panic if used on a `WASM`
440
//! platform that does not support timers.
441
//!
442
//! Note also that if the runtime becomes indefinitely idle, it will panic
443
//! immediately instead of blocking forever. On platforms that don't support
444
//! time, this means that the runtime can never be idle in any way.
445
//!
446
//! ## Unstable `WASM` support
447
//!
448
//! Tokio also has unstable support for some additional `WASM` features. This
449
//! requires the use of the `tokio_unstable` flag.
450
//!
451
//! Using this flag enables the use of `tokio::net` on the wasm32-wasi target.
452
//! However, not all methods are available on the networking types as `WASI`
453
//! currently does not support the creation of new sockets from within `WASM`.
454
//! Because of this, sockets must currently be created via the `FromRawFd`
455
//! trait.
456
457
// Test that pointer width is compatible. This asserts that e.g. usize is at
458
// least 32 bits, which a lot of components in Tokio currently assumes.
459
//
460
// TODO: improve once we have MSRV access to const eval to make more flexible.
461
#[cfg(not(any(target_pointer_width = "32", target_pointer_width = "64")))]
462
compile_error! {
463
    "Tokio requires the platform pointer width to be at least 32 bits"
464
}
465
466
#[cfg(all(
467
    not(tokio_unstable),
468
    target_family = "wasm",
469
    any(
470
        feature = "fs",
471
        feature = "io-std",
472
        feature = "net",
473
        feature = "process",
474
        feature = "rt-multi-thread",
475
        feature = "signal"
476
    )
477
))]
478
compile_error!("Only features sync,macros,io-util,rt,time are supported on wasm.");
479
480
#[cfg(all(not(tokio_unstable), feature = "io-uring"))]
481
compile_error!("The `io-uring` feature requires `--cfg tokio_unstable`.");
482
483
#[cfg(all(not(tokio_unstable), feature = "taskdump"))]
484
compile_error!("The `taskdump` feature requires `--cfg tokio_unstable`.");
485
486
#[cfg(all(
487
    feature = "taskdump",
488
    not(doc),
489
    not(all(
490
        target_os = "linux",
491
        any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")
492
    ))
493
))]
494
compile_error!(
495
    "The `taskdump` feature is only currently supported on \
496
linux, on `aarch64`, `x86` and `x86_64`."
497
);
498
499
// Includes re-exports used by macros.
500
//
501
// This module is not intended to be part of the public API. In general, any
502
// `doc(hidden)` code is not part of Tokio's public and stable API.
503
#[macro_use]
504
#[doc(hidden)]
505
pub mod macros;
506
507
cfg_fs! {
508
    pub mod fs;
509
}
510
511
mod future;
512
513
pub mod io;
514
pub mod net;
515
516
mod loom;
517
518
cfg_process! {
519
    pub mod process;
520
}
521
522
#[cfg(any(
523
    feature = "fs",
524
    feature = "io-std",
525
    feature = "net",
526
    all(windows, feature = "process"),
527
))]
528
mod blocking;
529
530
cfg_rt! {
531
    pub mod runtime;
532
}
533
cfg_not_rt! {
534
    pub(crate) mod runtime;
535
}
536
537
cfg_signal! {
538
    pub mod signal;
539
}
540
541
cfg_signal_internal! {
542
    #[cfg(not(feature = "signal"))]
543
    #[allow(dead_code)]
544
    #[allow(unreachable_pub)]
545
    pub(crate) mod signal;
546
}
547
548
cfg_sync! {
549
    pub mod sync;
550
}
551
cfg_not_sync! {
552
    mod sync;
553
}
554
555
// Currently, task module does not expose any public API outside `rt`
556
// feature, so we mark it in the docs. This happens only to docs to
557
// avoid introducing breaking changes by restricting the visibility
558
// of the task module.
559
#[cfg_attr(docsrs, doc(cfg(feature = "rt")))]
560
pub mod task;
561
cfg_rt! {
562
    pub use task::spawn;
563
}
564
565
cfg_time! {
566
    pub mod time;
567
}
568
569
mod trace {
570
    cfg_taskdump! {
571
        pub(crate) use crate::runtime::task::trace::trace_leaf;
572
    }
573
574
    cfg_not_taskdump! {
575
        #[inline(always)]
576
        #[allow(dead_code)]
577
0
        pub(crate) fn trace_leaf(_: &mut std::task::Context<'_>) -> std::task::Poll<()> {
578
0
            std::task::Poll::Ready(())
579
0
        }
580
    }
581
582
    #[cfg_attr(not(feature = "sync"), allow(dead_code))]
583
0
    pub(crate) async fn async_trace_leaf() {
584
0
        std::future::poll_fn(trace_leaf).await
585
0
    }
586
}
587
588
mod util;
589
590
/// Due to the `Stream` trait's inclusion in `std` landing later than Tokio's 1.0
591
/// release, most of the Tokio stream utilities have been moved into the [`tokio-stream`]
592
/// crate.
593
///
594
/// # Why was `Stream` not included in Tokio 1.0?
595
///
596
/// Originally, we had planned to ship Tokio 1.0 with a stable `Stream` type
597
/// but unfortunately the [RFC] had not been merged in time for `Stream` to
598
/// reach `std` on a stable compiler in time for the 1.0 release of Tokio. For
599
/// this reason, the team has decided to move all `Stream` based utilities to
600
/// the [`tokio-stream`] crate. While this is not ideal, once `Stream` has made
601
/// it into the standard library and the `MSRV` period has passed, we will implement
602
/// stream for our different types.
603
///
604
/// While this may seem unfortunate, not all is lost as you can get much of the
605
/// `Stream` support with `async/await` and `while let` loops. It is also possible
606
/// to create a `impl Stream` from `async fn` using the [`async-stream`] crate.
607
///
608
/// [`tokio-stream`]: https://docs.rs/tokio-stream
609
/// [`async-stream`]: https://docs.rs/async-stream
610
/// [RFC]: https://github.com/rust-lang/rfcs/pull/2996
611
///
612
/// # Example
613
///
614
/// Convert a [`sync::mpsc::Receiver`] to an `impl Stream`.
615
///
616
/// ```rust,no_run
617
/// use tokio::sync::mpsc;
618
///
619
/// let (tx, mut rx) = mpsc::channel::<usize>(16);
620
///
621
/// let stream = async_stream::stream! {
622
///     while let Some(item) = rx.recv().await {
623
///         yield item;
624
///     }
625
/// };
626
/// ```
627
pub mod stream {}
628
629
// local re-exports of platform specific things, allowing for decent
630
// documentation to be shimmed in on docs.rs
631
632
#[cfg(all(docsrs, unix))]
633
pub mod doc;
634
635
#[cfg(any(feature = "net", feature = "fs"))]
636
#[cfg(all(docsrs, unix))]
637
#[allow(unused)]
638
pub(crate) use self::doc::os;
639
640
#[cfg(not(all(docsrs, unix)))]
641
#[allow(unused)]
642
pub(crate) use std::os;
643
644
cfg_macros! {
645
    /// Implementation detail of the `select!` macro. This macro is **not**
646
    /// intended to be used as part of the public API and is permitted to
647
    /// change.
648
    #[doc(hidden)]
649
    pub use tokio_macros::select_priv_declare_output_enum;
650
651
    /// Implementation detail of the `select!` macro. This macro is **not**
652
    /// intended to be used as part of the public API and is permitted to
653
    /// change.
654
    #[doc(hidden)]
655
    pub use tokio_macros::select_priv_clean_pattern;
656
657
    cfg_rt! {
658
        #[cfg(feature = "rt-multi-thread")]
659
        #[cfg_attr(docsrs, doc(cfg(feature = "macros")))]
660
        #[doc(inline)]
661
        pub use tokio_macros::main;
662
663
        #[cfg(feature = "rt-multi-thread")]
664
        #[cfg_attr(docsrs, doc(cfg(feature = "macros")))]
665
        #[doc(inline)]
666
        pub use tokio_macros::test;
667
668
        cfg_not_rt_multi_thread! {
669
            #[doc(inline)]
670
            pub use tokio_macros::main_rt as main;
671
672
            #[doc(inline)]
673
            pub use tokio_macros::test_rt as test;
674
        }
675
    }
676
677
    // Always fail if rt is not enabled.
678
    cfg_not_rt! {
679
        #[doc(inline)]
680
        pub use tokio_macros::main_fail as main;
681
682
        #[doc(inline)]
683
        pub use tokio_macros::test_fail as test;
684
    }
685
}
686
687
// TODO: rm
688
#[cfg(feature = "io-util")]
689
#[cfg(test)]
690
fn is_unpin<T: Unpin>() {}
691
692
/// fuzz test (`fuzz_linked_list`)
693
#[cfg(fuzzing)]
694
pub mod fuzz;