1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
13 //! ## The threading model
15 //! An executing Rust program consists of a collection of native OS threads,
16 //! each with their own stack and local state.
18 //! Communication between threads can be done through
19 //! [channels](../../std/sync/mpsc/index.html), Rust's message-passing
20 //! types, along with [other forms of thread
21 //! synchronization](../../std/sync/index.html) and shared-memory data
22 //! structures. In particular, types that are guaranteed to be
23 //! threadsafe are easily shared between threads using the
24 //! atomically-reference-counted container,
25 //! [`Arc`](../../std/sync/struct.Arc.html).
27 //! Fatal logic errors in Rust cause *thread panic*, during which
28 //! a thread will unwind the stack, running destructors and freeing
29 //! owned resources. Thread panic is unrecoverable from within
30 //! the panicking thread (i.e. there is no 'try/catch' in Rust), but
31 //! the panic may optionally be detected from a different thread. If
32 //! the main thread panics, the application will exit with a non-zero
35 //! When the main thread of a Rust program terminates, the entire program shuts
36 //! down, even if other threads are still running. However, this module provides
37 //! convenient facilities for automatically waiting for the termination of a
38 //! child thread (i.e., join).
40 //! ## The `Thread` type
42 //! Threads are represented via the `Thread` type, which you can
43 //! get in one of two ways:
45 //! * By spawning a new thread, e.g. using the `thread::spawn` function.
46 //! * By requesting the current thread, using the `thread::current` function.
48 //! Threads can be named, and provide some built-in support for low-level
49 //! synchronization (described below).
51 //! The `thread::current()` function is available even for threads not spawned
52 //! by the APIs of this module.
54 //! ## Spawning a thread
56 //! A new thread can be spawned using the `thread::spawn` function:
61 //! thread::spawn(move || {
66 //! In this example, the spawned thread is "detached" from the current
67 //! thread. This means that it can outlive its parent (the thread that spawned
68 //! it), unless this parent is the main thread.
72 //! Often a parent thread uses a child thread to perform some particular task,
73 //! and at some point must wait for the child to complete before continuing.
74 //! For this scenario, use the `thread::scoped` function:
79 //! let guard = thread::scoped(move || {
83 //! // do some other work in the meantime
84 //! let output = guard.join();
87 //! The `scoped` function doesn't return a `Thread` directly; instead,
88 //! it returns a *join guard*. The join guard is an RAII-style guard
89 //! that will automatically join the child thread (block until it
90 //! terminates) when it is dropped. You can join the child thread in
91 //! advance by calling the `join` method on the guard, which will also
92 //! return the result produced by the thread. A handle to the thread
93 //! itself is available via the `thread` method of the join guard.
95 //! ## Configuring threads
97 //! A new thread can be configured before it is spawned via the `Builder` type,
98 //! which currently allows you to set the name, stack size, and writers for
99 //! `println!` and `panic!` for the child thread:
104 //! thread::Builder::new().name("child1".to_string()).spawn(move || {
105 //! println!("Hello, world!");
109 //! ## Blocking support: park and unpark
111 //! Every thread is equipped with some basic low-level blocking support, via the
112 //! `park` and `unpark` functions.
114 //! Conceptually, each `Thread` handle has an associated token, which is
115 //! initially not present:
117 //! * The `thread::park()` function blocks the current thread unless or until
118 //! the token is available for its thread handle, at which point it atomically
119 //! consumes the token. It may also return *spuriously*, without consuming the
120 //! token. `thread::park_timeout()` does the same, but allows specifying a
121 //! maximum time to block the thread for.
123 //! * The `unpark()` method on a `Thread` atomically makes the token available
124 //! if it wasn't already.
126 //! In other words, each `Thread` acts a bit like a semaphore with initial count
127 //! 0, except that the semaphore is *saturating* (the count cannot go above 1),
128 //! and can return spuriously.
130 //! The API is typically used by acquiring a handle to the current thread,
131 //! placing that handle in a shared data structure so that other threads can
132 //! find it, and then `park`ing. When some desired condition is met, another
133 //! thread calls `unpark` on the handle.
135 //! The motivation for this design is twofold:
137 //! * It avoids the need to allocate mutexes and condvars when building new
138 //! synchronization primitives; the threads already provide basic blocking/signaling.
140 //! * It can be implemented very efficiently on many platforms.
142 //! ## Thread-local storage
144 //! This module also provides an implementation of thread local storage for Rust
145 //! programs. Thread local storage is a method of storing data into a global
146 //! variable which each thread in the program will have its own copy of.
147 //! Threads do not share this data, so accesses do not need to be synchronized.
149 //! At a high level, this module provides two variants of storage:
151 //! * Owned thread-local storage. This is a type of thread local key which
152 //! owns the value that it contains, and will destroy the value when the
153 //! thread exits. This variant is created with the `thread_local!` macro and
154 //! can contain any value which is `'static` (no borrowed pointers).
156 //! * Scoped thread-local storage. This type of key is used to store a reference
157 //! to a value into local storage temporarily for the scope of a function
158 //! call. There are no restrictions on what types of values can be placed
161 //! Both forms of thread local storage provide an accessor function, `with`,
162 //! which will yield a shared reference to the value to the specified
163 //! closure. Thread-local keys only allow shared access to values as there is no
164 //! way to guarantee uniqueness if a mutable borrow was allowed. Most values
165 //! will want to make use of some form of **interior mutability** through the
166 //! `Cell` or `RefCell` types.
168 #![stable(feature = "rust1", since = "1.0.0")]
170 #[stable(feature = "rust1", since = "1.0.0")]
171 pub use self::__local::{LocalKey, LocalKeyState};
173 #[unstable(feature = "scoped_tls",
174 reason = "scoped TLS has yet to have wide enough use to fully consider \
175 stabilizing its interface")]
176 pub use self::__scoped::ScopedKey;
181 use cell::UnsafeCell;
184 use marker::PhantomData;
185 use rt::{self, unwind};
186 use sync::{Mutex, Condvar, Arc};
187 use sys::thread as imp;
188 use sys_common::{stack, thread_info};
192 ////////////////////////////////////////////////////////////////////////////////
193 // Thread-local storage
194 ////////////////////////////////////////////////////////////////////////////////
198 #[path = "local.rs"] pub mod __local;
202 #[path = "scoped.rs"] pub mod __scoped;
204 ////////////////////////////////////////////////////////////////////////////////
206 ////////////////////////////////////////////////////////////////////////////////
208 /// Thread configuration. Provides detailed control over the properties
209 /// and behavior of new threads.
210 #[stable(feature = "rust1", since = "1.0.0")]
212 // A name for the thread-to-be, for identification in panic messages
213 name: Option<String>,
214 // The size of the stack for the spawned thread
215 stack_size: Option<usize>,
219 /// Generate the base configuration for spawning a thread, from which
220 /// configuration methods can be chained.
221 #[stable(feature = "rust1", since = "1.0.0")]
222 pub fn new() -> Builder {
229 /// Name the thread-to-be. Currently the name is used for identification
230 /// only in panic messages.
231 #[stable(feature = "rust1", since = "1.0.0")]
232 pub fn name(mut self, name: String) -> Builder {
233 self.name = Some(name);
237 /// Set the size of the stack for the new thread.
238 #[stable(feature = "rust1", since = "1.0.0")]
239 pub fn stack_size(mut self, size: usize) -> Builder {
240 self.stack_size = Some(size);
244 /// Spawn a new thread, and return a join handle for it.
246 /// The child thread may outlive the parent (unless the parent thread
247 /// is the main thread; the whole process is terminated when the main
248 /// thread finishes.) The join handle can be used to block on
249 /// termination of the child thread, including recovering its panics.
253 /// Unlike the `spawn` free function, this method yields an
254 /// `io::Result` to capture any failure to create the thread at
256 #[stable(feature = "rust1", since = "1.0.0")]
257 pub fn spawn<F>(self, f: F) -> io::Result<JoinHandle> where
258 F: FnOnce(), F: Send + 'static
260 self.spawn_inner(Thunk::new(f)).map(|i| JoinHandle(i))
263 /// Spawn a new child thread that must be joined within a given
264 /// scope, and return a `JoinGuard`.
266 /// The join guard can be used to explicitly join the child thread (via
267 /// `join`), returning `Result<T>`, or it will implicitly join the child
268 /// upon being dropped. Because the child thread may refer to data on the
269 /// current thread's stack (hence the "scoped" name), it cannot be detached;
270 /// it *must* be joined before the relevant stack frame is popped. See the
271 /// module documentation for additional details.
275 /// Unlike the `scoped` free function, this method yields an
276 /// `io::Result` to capture any failure to create the thread at
278 #[stable(feature = "rust1", since = "1.0.0")]
279 pub fn scoped<'a, T, F>(self, f: F) -> io::Result<JoinGuard<'a, T>> where
280 T: Send + 'a, F: FnOnce() -> T, F: Send + 'a
282 self.spawn_inner(Thunk::new(f)).map(|inner| {
283 JoinGuard { inner: inner, _marker: PhantomData }
287 fn spawn_inner<T: Send>(self, f: Thunk<(), T>) -> io::Result<JoinInner<T>> {
288 let Builder { name, stack_size } = self;
290 let stack_size = stack_size.unwrap_or(rt::min_stack());
292 let my_thread = Thread::new(name);
293 let their_thread = my_thread.clone();
295 let my_packet = Packet(Arc::new(UnsafeCell::new(None)));
296 let their_packet = Packet(my_packet.0.clone());
298 // Spawning a new OS thread guarantees that __morestack will never get
299 // triggered, but we must manually set up the actual stack bounds once
300 // this function starts executing. This raises the lower limit by a bit
301 // because by the time that this function is executing we've already
302 // consumed at least a little bit of stack (we don't know the exact byte
303 // address at which our stack started).
305 let something_around_the_top_of_the_stack = 1;
306 let addr = &something_around_the_top_of_the_stack as *const i32;
307 let my_stack_top = addr as usize;
308 let my_stack_bottom = my_stack_top - stack_size + 1024;
310 if let Some(name) = their_thread.name() {
313 stack::record_os_managed_stack_bounds(my_stack_bottom,
315 thread_info::set(imp::guard::current(), their_thread);
318 let mut output = None;
320 let ptr = &mut output;
322 // There are two primary reasons that general try/catch is
323 // unsafe. The first is that we do not support nested
324 // try/catch. The fact that this is happening in a newly-spawned
325 // thread suffices. The second is that unwinding while unwinding
326 // is not defined. We take care of that by having an
327 // 'unwinding' flag in the thread itself. For these reasons,
328 // this unsafety should be ok.
330 unwind::try(move || *ptr = Some(f.invoke(())))
334 *their_packet.0.get() = Some(match (output, try_result) {
335 (Some(data), Ok(_)) => Ok(data),
336 (None, Err(cause)) => Err(cause),
343 native: try!(unsafe { imp::create(stack_size, Thunk::new(main)) }),
351 ////////////////////////////////////////////////////////////////////////////////
353 ////////////////////////////////////////////////////////////////////////////////
355 /// Spawn a new thread, returning a `JoinHandle` for it.
357 /// The join handle will implicitly *detach* the child thread upon being
358 /// dropped. In this case, the child thread may outlive the parent (unless
359 /// the parent thread is the main thread; the whole process is terminated when
360 /// the main thread finishes.) Additionally, the join handle provides a `join`
361 /// method that can be used to join the child thread. If the child thread
362 /// panics, `join` will return an `Err` containing the argument given to
367 /// Panicks if the OS fails to create a thread; use `Builder::spawn`
368 /// to recover from such errors.
369 #[stable(feature = "rust1", since = "1.0.0")]
370 pub fn spawn<F>(f: F) -> JoinHandle where F: FnOnce(), F: Send + 'static {
371 Builder::new().spawn(f).unwrap()
374 /// Spawn a new *scoped* thread, returning a `JoinGuard` for it.
376 /// The join guard can be used to explicitly join the child thread (via
377 /// `join`), returning `Result<T>`, or it will implicitly join the child
378 /// upon being dropped. Because the child thread may refer to data on the
379 /// current thread's stack (hence the "scoped" name), it cannot be detached;
380 /// it *must* be joined before the relevant stack frame is popped. See the
381 /// module documentation for additional details.
385 /// Panicks if the OS fails to create a thread; use `Builder::scoped`
386 /// to recover from such errors.
387 #[stable(feature = "rust1", since = "1.0.0")]
388 pub fn scoped<'a, T, F>(f: F) -> JoinGuard<'a, T> where
389 T: Send + 'a, F: FnOnce() -> T, F: Send + 'a
391 Builder::new().scoped(f).unwrap()
394 /// Gets a handle to the thread that invokes it.
395 #[stable(feature = "rust1", since = "1.0.0")]
396 pub fn current() -> Thread {
397 thread_info::current_thread()
400 /// Cooperatively give up a timeslice to the OS scheduler.
401 #[stable(feature = "rust1", since = "1.0.0")]
403 unsafe { imp::yield_now() }
406 /// Determines whether the current thread is unwinding because of panic.
408 #[stable(feature = "rust1", since = "1.0.0")]
409 pub fn panicking() -> bool {
413 /// Invoke a closure, capturing the cause of panic if one occurs.
415 /// This function will return `Ok(())` if the closure does not panic, and will
416 /// return `Err(cause)` if the closure panics. The `cause` returned is the
417 /// object with which panic was originally invoked.
419 /// It is currently undefined behavior to unwind from Rust code into foreign
420 /// code, so this function is particularly useful when Rust is called from
421 /// another language (normally C). This can run arbitrary Rust code, capturing a
422 /// panic and allowing a graceful handling of the error.
424 /// It is **not** recommended to use this function for a general try/catch
425 /// mechanism. The `Result` type is more appropriate to use for functions that
426 /// can fail on a regular basis.
428 /// The closure provided is required to adhere to the `'static` bound to ensure
429 /// that it cannot reference data in the parent stack frame, mitigating problems
430 /// with exception safety. Furthermore, a `Send` bound is also required,
431 /// providing the same safety guarantees as `thread::spawn` (ensuring the
432 /// closure is properly isolated from the parent).
437 /// # #![feature(catch_panic)]
440 /// let result = thread::catch_panic(|| {
441 /// println!("hello!");
443 /// assert!(result.is_ok());
445 /// let result = thread::catch_panic(|| {
446 /// panic!("oh no!");
448 /// assert!(result.is_err());
450 #[unstable(feature = "catch_panic", reason = "recent API addition")]
451 pub fn catch_panic<F, R>(f: F) -> Result<R>
452 where F: FnOnce() -> R + Send + 'static
454 let mut result = None;
456 let result = &mut result;
457 try!(::rt::unwind::try(move || *result = Some(f())))
462 /// Put the current thread to sleep for the specified amount of time.
464 /// The thread may sleep longer than the duration specified due to scheduling
465 /// specifics or platform-dependent functionality. Note that on unix platforms
466 /// this function will not return early due to a signal being received or a
468 #[stable(feature = "rust1", since = "1.0.0")]
469 pub fn sleep_ms(ms: u32) {
470 imp::sleep(Duration::milliseconds(ms as i64))
473 /// Deprecated: use `sleep_ms` instead.
474 #[unstable(feature = "thread_sleep",
475 reason = "recently added, needs an RFC, and `Duration` itself is \
477 #[deprecated(since = "1.0.0", reason = "use sleep_ms instead")]
478 pub fn sleep(dur: Duration) {
482 /// Block unless or until the current thread's token is made available (may wake spuriously).
484 /// See the module doc for more detail.
486 // The implementation currently uses the trivial strategy of a Mutex+Condvar
487 // with wakeup flag, which does not actually allow spurious wakeups. In the
488 // future, this will be implemented in a more efficient way, perhaps along the lines of
489 // http://cr.openjdk.java.net/~stefank/6989984.1/raw_files/new/src/os/linux/vm/os_linux.cpp
490 // or futuxes, and in either case may allow spurious wakeups.
491 #[stable(feature = "rust1", since = "1.0.0")]
493 let thread = current();
494 let mut guard = thread.inner.lock.lock().unwrap();
496 guard = thread.inner.cvar.wait(guard).unwrap();
501 /// Block unless or until the current thread's token is made available or
502 /// the specified duration has been reached (may wake spuriously).
504 /// The semantics of this function are equivalent to `park()` except that the
505 /// thread will be blocked for roughly no longer than *duration*. This method
506 /// should not be used for precise timing due to anomalies such as
507 /// preemption or platform differences that may not cause the maximum
508 /// amount of time waited to be precisely *duration* long.
510 /// See the module doc for more detail.
511 #[stable(feature = "rust1", since = "1.0.0")]
512 pub fn park_timeout_ms(ms: u32) {
513 let thread = current();
514 let mut guard = thread.inner.lock.lock().unwrap();
516 let (g, _) = thread.inner.cvar.wait_timeout_ms(guard, ms).unwrap();
522 /// Deprecated: use `park_timeout_ms`
523 #[unstable(feature = "std_misc", reason = "recently introduced, depends on Duration")]
524 #[deprecated(since = "1.0.0", reason = "use park_timeout_ms instead")]
525 pub fn park_timeout(duration: Duration) {
526 park_timeout_ms(duration.num_milliseconds() as u32)
529 ////////////////////////////////////////////////////////////////////////////////
531 ////////////////////////////////////////////////////////////////////////////////
533 /// The internal representation of a `Thread` handle
535 name: Option<String>,
536 lock: Mutex<bool>, // true when there is a buffered unpark
540 unsafe impl Sync for Inner {}
543 #[stable(feature = "rust1", since = "1.0.0")]
544 /// A handle to a thread.
550 // Used only internally to construct a thread object without spawning
551 fn new(name: Option<String>) -> Thread {
553 inner: Arc::new(Inner {
555 lock: Mutex::new(false),
556 cvar: Condvar::new(),
561 /// Atomically makes the handle's token available if it is not already.
563 /// See the module doc for more detail.
564 #[stable(feature = "rust1", since = "1.0.0")]
565 pub fn unpark(&self) {
566 let mut guard = self.inner.lock.lock().unwrap();
569 self.inner.cvar.notify_one();
573 /// Get the thread's name.
574 #[stable(feature = "rust1", since = "1.0.0")]
575 pub fn name(&self) -> Option<&str> {
576 self.inner.name.as_ref().map(|s| &**s)
580 #[stable(feature = "rust1", since = "1.0.0")]
581 impl fmt::Debug for Thread {
582 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
583 fmt::Debug::fmt(&self.name(), f)
587 // a hack to get around privacy restrictions
588 impl thread_info::NewThread for Thread {
589 fn new(name: Option<String>) -> Thread { Thread::new(name) }
592 ////////////////////////////////////////////////////////////////////////////////
593 // JoinHandle and JoinGuard
594 ////////////////////////////////////////////////////////////////////////////////
596 /// Indicates the manner in which a thread exited.
598 /// A thread that completes without panicking is considered to exit successfully.
599 #[stable(feature = "rust1", since = "1.0.0")]
600 pub type Result<T> = ::result::Result<T, Box<Any + Send + 'static>>;
602 struct Packet<T>(Arc<UnsafeCell<Option<Result<T>>>>);
604 unsafe impl<T:Send> Send for Packet<T> {}
605 unsafe impl<T> Sync for Packet<T> {}
607 /// Inner representation for JoinHandle and JoinGuard
608 struct JoinInner<T> {
609 native: imp::rust_thread,
615 impl<T> JoinInner<T> {
616 fn join(&mut self) -> Result<T> {
617 assert!(!self.joined);
618 unsafe { imp::join(self.native) };
621 (*self.packet.0.get()).take().unwrap()
626 /// An owned permission to join on a thread (block on its termination).
628 /// Unlike a `JoinGuard`, a `JoinHandle` *detaches* the child thread
629 /// when it is dropped, rather than automatically joining on drop.
631 /// Due to platform restrictions, it is not possible to `Clone` this
632 /// handle: the ability to join a child thread is a uniquely-owned
634 #[stable(feature = "rust1", since = "1.0.0")]
635 pub struct JoinHandle(JoinInner<()>);
638 /// Extract a handle to the underlying thread
639 #[stable(feature = "rust1", since = "1.0.0")]
640 pub fn thread(&self) -> &Thread {
644 /// Wait for the associated thread to finish.
646 /// If the child thread panics, `Err` is returned with the parameter given
648 #[stable(feature = "rust1", since = "1.0.0")]
649 pub fn join(mut self) -> Result<()> {
654 #[stable(feature = "rust1", since = "1.0.0")]
655 impl Drop for JoinHandle {
658 unsafe { imp::detach(self.0.native) }
663 /// An RAII-style guard that will block until thread termination when dropped.
665 /// The type `T` is the return type for the thread's main function.
667 /// Joining on drop is necessary to ensure memory safety when stack
668 /// data is shared between a parent and child thread.
670 /// Due to platform restrictions, it is not possible to `Clone` this
671 /// handle: the ability to join a child thread is a uniquely-owned
673 #[must_use = "thread will be immediately joined if `JoinGuard` is not used"]
674 #[stable(feature = "rust1", since = "1.0.0")]
675 pub struct JoinGuard<'a, T: Send + 'a> {
677 _marker: PhantomData<&'a T>,
680 #[stable(feature = "rust1", since = "1.0.0")]
681 unsafe impl<'a, T: Send + 'a> Sync for JoinGuard<'a, T> {}
683 impl<'a, T: Send + 'a> JoinGuard<'a, T> {
684 /// Extract a handle to the thread this guard will join on.
685 #[stable(feature = "rust1", since = "1.0.0")]
686 pub fn thread(&self) -> &Thread {
690 /// Wait for the associated thread to finish, returning the result of the
691 /// thread's calculation.
695 /// Panics on the child thread are propagated by panicking the parent.
696 #[stable(feature = "rust1", since = "1.0.0")]
697 pub fn join(mut self) -> T {
698 match self.inner.join() {
700 Err(_) => panic!("child thread {:?} panicked", self.thread()),
706 #[stable(feature = "rust1", since = "1.0.0")]
707 impl<'a, T: Send + 'a> Drop for JoinGuard<'a, T> {
709 if !self.inner.joined {
710 if self.inner.join().is_err() {
711 panic!("child thread {:?} panicked", self.thread());
717 ////////////////////////////////////////////////////////////////////////////////
719 ////////////////////////////////////////////////////////////////////////////////
726 use sync::mpsc::{channel, Sender};
728 use std::old_io::{ChanReader, ChanWriter};
729 use super::{Builder};
735 // !!! These tests are dangerous. If something is buggy, they will hang, !!!
736 // !!! instead of exiting cleanly. This might wedge the buildbots. !!!
739 fn test_unnamed_thread() {
740 thread::spawn(move|| {
741 assert!(thread::current().name().is_none());
742 }).join().ok().unwrap();
746 fn test_named_thread() {
747 Builder::new().name("ada lovelace".to_string()).scoped(move|| {
748 assert!(thread::current().name().unwrap() == "ada lovelace".to_string());
753 fn test_run_basic() {
754 let (tx, rx) = channel();
755 thread::spawn(move|| {
756 tx.send(()).unwrap();
762 fn test_join_success() {
763 assert!(thread::scoped(move|| -> String {
764 "Success!".to_string()
765 }).join() == "Success!");
769 fn test_join_panic() {
770 match thread::spawn(move|| {
773 result::Result::Err(_) => (),
774 result::Result::Ok(()) => panic!()
779 fn test_scoped_success() {
780 let res = thread::scoped(move|| -> String {
781 "Success!".to_string()
783 assert!(res == "Success!");
788 fn test_scoped_panic() {
789 thread::scoped(|| panic!()).join();
794 fn test_scoped_implicit_panic() {
795 let _ = thread::scoped(|| panic!());
799 fn test_spawn_sched() {
802 let (tx, rx) = channel();
804 fn f(i: i32, tx: Sender<()>) {
806 thread::spawn(move|| {
808 tx.send(()).unwrap();
820 fn test_spawn_sched_childs_on_default_sched() {
821 let (tx, rx) = channel();
823 thread::spawn(move|| {
824 thread::spawn(move|| {
825 tx.send(()).unwrap();
832 fn avoid_copying_the_body<F>(spawnfn: F) where F: FnOnce(Thunk<'static>) {
833 let (tx, rx) = channel();
835 let x: Box<_> = box 1;
836 let x_in_parent = (&*x) as *const i32 as usize;
838 spawnfn(Thunk::new(move|| {
839 let x_in_child = (&*x) as *const i32 as usize;
840 tx.send(x_in_child).unwrap();
843 let x_in_child = rx.recv().unwrap();
844 assert_eq!(x_in_parent, x_in_child);
848 fn test_avoid_copying_the_body_spawn() {
849 avoid_copying_the_body(|v| {
850 thread::spawn(move || v.invoke(()));
855 fn test_avoid_copying_the_body_thread_spawn() {
856 avoid_copying_the_body(|f| {
857 thread::spawn(move|| {
864 fn test_avoid_copying_the_body_join() {
865 avoid_copying_the_body(|f| {
866 let _ = thread::spawn(move|| {
873 fn test_child_doesnt_ref_parent() {
874 // If the child refcounts the parent task, this will stack overflow when
875 // climbing the task tree to dereference each ancestor. (See #1789)
876 // (well, it would if the constant were 8000+ - I lowered it to be more
877 // valgrind-friendly. try this at home, instead..!)
878 const GENERATIONS: u32 = 16;
879 fn child_no(x: u32) -> Thunk<'static> {
880 return Thunk::new(move|| {
882 thread::spawn(move|| child_no(x+1).invoke(()));
886 thread::spawn(|| child_no(0).invoke(()));
890 fn test_simple_newsched_spawn() {
891 thread::spawn(move || {});
895 fn test_try_panic_message_static_str() {
896 match thread::spawn(move|| {
897 panic!("static string");
900 type T = &'static str;
901 assert!(e.is::<T>());
902 assert_eq!(*e.downcast::<T>().unwrap(), "static string");
909 fn test_try_panic_message_owned_str() {
910 match thread::spawn(move|| {
911 panic!("owned string".to_string());
915 assert!(e.is::<T>());
916 assert_eq!(*e.downcast::<T>().unwrap(), "owned string".to_string());
923 fn test_try_panic_message_any() {
924 match thread::spawn(move|| {
925 panic!(box 413u16 as Box<Any + Send>);
928 type T = Box<Any + Send>;
929 assert!(e.is::<T>());
930 let any = e.downcast::<T>().unwrap();
931 assert!(any.is::<u16>());
932 assert_eq!(*any.downcast::<u16>().unwrap(), 413);
939 fn test_try_panic_message_unit_struct() {
942 match thread::spawn(move|| {
945 Err(ref e) if e.is::<Juju>() => {}
946 Err(_) | Ok(()) => panic!()
951 fn test_park_timeout_unpark_before() {
953 thread::current().unpark();
954 thread::park_timeout_ms(u32::MAX);
959 fn test_park_timeout_unpark_not_called() {
961 thread::park_timeout_ms(10);
966 fn test_park_timeout_unpark_called_other_thread() {
970 let th = thread::current();
972 let _guard = thread::spawn(move || {
973 old_io::timer::sleep(Duration::milliseconds(50));
977 thread::park_timeout_ms(u32::MAX);
982 fn sleep_ms_smoke() {
986 // NOTE: the corresponding test for stderr is in run-pass/task-stderr, due
987 // to the test harness apparently interfering with stderr configuration.