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. Threads can be named, and
17 //! provide some built-in support for low-level synchronization.
19 //! Communication between threads can be done through
20 //! [channels](../../std/sync/mpsc/index.html), Rust's message-passing
21 //! types, along with [other forms of thread
22 //! synchronization](../../std/sync/index.html) and shared-memory data
23 //! structures. In particular, types that are guaranteed to be
24 //! threadsafe are easily shared between threads using the
25 //! atomically-reference-counted container,
26 //! [`Arc`](../../std/sync/struct.Arc.html).
28 //! Fatal logic errors in Rust cause *thread panic*, during which
29 //! a thread will unwind the stack, running destructors and freeing
30 //! owned resources. Thread panic is unrecoverable from within
31 //! the panicking thread (i.e. there is no 'try/catch' in Rust), but
32 //! the panic may optionally be detected from a different thread. If
33 //! the main thread panics, the application will exit with a non-zero
36 //! When the main thread of a Rust program terminates, the entire program shuts
37 //! down, even if other threads are still running. However, this module provides
38 //! convenient facilities for automatically waiting for the termination of a
39 //! child thread (i.e., join).
41 //! ## Spawning a thread
43 //! A new thread can be spawned using the `thread::spawn` function:
48 //! thread::spawn(move || {
53 //! In this example, the spawned thread is "detached" from the current
54 //! thread. This means that it can outlive its parent (the thread that spawned
55 //! it), unless this parent is the main thread.
57 //! The parent thread can also wait on the completion of the child
58 //! thread; a call to `spawn` produces a `JoinHandle`, which provides
59 //! a `join` method for waiting:
64 //! let child = thread::spawn(move || {
68 //! let res = child.join();
71 //! The `join` method returns a `Result` containing `Ok` of the final
72 //! value produced by the child thread, or `Err` of the value given to
73 //! a call to `panic!` if the child panicked.
75 //! ## Configuring threads
77 //! A new thread can be configured before it is spawned via the `Builder` type,
78 //! which currently allows you to set the name and stack size for the child thread:
81 //! # #![allow(unused_must_use)]
84 //! thread::Builder::new().name("child1".to_string()).spawn(move || {
85 //! println!("Hello, world!");
89 //! ## The `Thread` type
91 //! Threads are represented via the `Thread` type, which you can get in one of
94 //! * By spawning a new thread, e.g. using the `thread::spawn` function, and
95 //! calling `thread()` on the `JoinHandle`.
96 //! * By requesting the current thread, using the `thread::current` function.
98 //! The `thread::current()` function is available even for threads not spawned
99 //! by the APIs of this module.
101 //! ## Blocking support: park and unpark
103 //! Every thread is equipped with some basic low-level blocking support, via the
104 //! `thread::park()` function and `thread::Thread::unpark()` method. `park()`
105 //! blocks the current thread, which can then be resumed from another thread by
106 //! calling the `unpark()` method on the blocked thread's handle.
108 //! Conceptually, each `Thread` handle has an associated token, which is
109 //! initially not present:
111 //! * The `thread::park()` function blocks the current thread unless or until
112 //! the token is available for its thread handle, at which point it atomically
113 //! consumes the token. It may also return *spuriously*, without consuming the
114 //! token. `thread::park_timeout()` does the same, but allows specifying a
115 //! maximum time to block the thread for.
117 //! * The `unpark()` method on a `Thread` atomically makes the token available
118 //! if it wasn't already.
120 //! In other words, each `Thread` acts a bit like a semaphore with initial count
121 //! 0, except that the semaphore is *saturating* (the count cannot go above 1),
122 //! and can return spuriously.
124 //! The API is typically used by acquiring a handle to the current thread,
125 //! placing that handle in a shared data structure so that other threads can
126 //! find it, and then `park`ing. When some desired condition is met, another
127 //! thread calls `unpark` on the handle.
129 //! The motivation for this design is twofold:
131 //! * It avoids the need to allocate mutexes and condvars when building new
132 //! synchronization primitives; the threads already provide basic blocking/signaling.
134 //! * It can be implemented very efficiently on many platforms.
136 //! ## Thread-local storage
138 //! This module also provides an implementation of thread local storage for Rust
139 //! programs. Thread local storage is a method of storing data into a global
140 //! variable which each thread in the program will have its own copy of.
141 //! Threads do not share this data, so accesses do not need to be synchronized.
143 //! At a high level, this module provides two variants of storage:
145 //! * Owned thread-local storage. This is a type of thread local key which
146 //! owns the value that it contains, and will destroy the value when the
147 //! thread exits. This variant is created with the `thread_local!` macro and
148 //! can contain any value which is `'static` (no borrowed pointers).
150 //! * Scoped thread-local storage. This type of key is used to store a reference
151 //! to a value into local storage temporarily for the scope of a function
152 //! call. There are no restrictions on what types of values can be placed
155 //! Both forms of thread local storage provide an accessor function, `with`,
156 //! which will yield a shared reference to the value to the specified
157 //! closure. Thread-local keys only allow shared access to values as there is no
158 //! way to guarantee uniqueness if a mutable borrow was allowed. Most values
159 //! will want to make use of some form of **interior mutability** through the
160 //! `Cell` or `RefCell` types.
162 #![stable(feature = "rust1", since = "1.0.0")]
165 use cell::UnsafeCell;
166 use ffi::{CStr, CString};
172 use sync::{Mutex, Condvar, Arc};
173 use sys::thread as imp;
174 use sys_common::thread_info;
175 use sys_common::util;
176 use sys_common::{AsInner, IntoInner};
179 ////////////////////////////////////////////////////////////////////////////////
180 // Thread-local storage
181 ////////////////////////////////////////////////////////////////////////////////
183 #[macro_use] mod local;
185 #[stable(feature = "rust1", since = "1.0.0")]
186 pub use self::local::{LocalKey, LocalKeyState};
188 #[unstable(feature = "libstd_thread_internals", issue = "0")]
189 #[cfg(target_thread_local)]
190 #[doc(hidden)] pub use self::local::elf::Key as __ElfLocalKeyInner;
191 #[unstable(feature = "libstd_thread_internals", issue = "0")]
192 #[doc(hidden)] pub use self::local::os::Key as __OsLocalKeyInner;
194 ////////////////////////////////////////////////////////////////////////////////
196 ////////////////////////////////////////////////////////////////////////////////
198 /// Thread configuration. Provides detailed control over the properties
199 /// and behavior of new threads.
200 #[stable(feature = "rust1", since = "1.0.0")]
202 // A name for the thread-to-be, for identification in panic messages
203 name: Option<String>,
204 // The size of the stack for the spawned thread
205 stack_size: Option<usize>,
209 /// Generates the base configuration for spawning a thread, from which
210 /// configuration methods can be chained.
211 #[stable(feature = "rust1", since = "1.0.0")]
212 pub fn new() -> Builder {
219 /// Names the thread-to-be. Currently the name is used for identification
220 /// only in panic messages.
227 /// let builder = thread::Builder::new()
228 /// .name("foo".into());
230 /// let handler = builder.spawn(|| {
231 /// assert_eq!(thread::current().name(), Some("foo"))
234 /// handler.join().unwrap();
236 #[stable(feature = "rust1", since = "1.0.0")]
237 pub fn name(mut self, name: String) -> Builder {
238 self.name = Some(name);
242 /// Sets the size of the stack for the new thread.
243 #[stable(feature = "rust1", since = "1.0.0")]
244 pub fn stack_size(mut self, size: usize) -> Builder {
245 self.stack_size = Some(size);
249 /// Spawns a new thread, and returns a join handle for it.
251 /// The child thread may outlive the parent (unless the parent thread
252 /// is the main thread; the whole process is terminated when the main
253 /// thread finishes). The join handle can be used to block on
254 /// termination of the child thread, including recovering its panics.
258 /// Unlike the `spawn` free function, this method yields an
259 /// `io::Result` to capture any failure to create the thread at
261 #[stable(feature = "rust1", since = "1.0.0")]
262 pub fn spawn<F, T>(self, f: F) -> io::Result<JoinHandle<T>> where
263 F: FnOnce() -> T, F: Send + 'static, T: Send + 'static
265 let Builder { name, stack_size } = self;
267 let stack_size = stack_size.unwrap_or(util::min_stack());
269 let my_thread = Thread::new(name);
270 let their_thread = my_thread.clone();
272 let my_packet : Arc<UnsafeCell<Option<Result<T>>>>
273 = Arc::new(UnsafeCell::new(None));
274 let their_packet = my_packet.clone();
277 if let Some(name) = their_thread.cname() {
278 imp::Thread::set_name(name);
281 thread_info::set(imp::guard::current(), their_thread);
282 let try_result = panic::catch_unwind(panic::AssertUnwindSafe(f));
283 *their_packet.get() = Some(try_result);
287 Ok(JoinHandle(JoinInner {
289 Some(imp::Thread::new(stack_size, Box::new(main))?)
292 packet: Packet(my_packet),
297 ////////////////////////////////////////////////////////////////////////////////
299 ////////////////////////////////////////////////////////////////////////////////
301 /// Spawns a new thread, returning a `JoinHandle` for it.
303 /// The join handle will implicitly *detach* the child thread upon being
304 /// dropped. In this case, the child thread may outlive the parent (unless
305 /// the parent thread is the main thread; the whole process is terminated when
306 /// the main thread finishes.) Additionally, the join handle provides a `join`
307 /// method that can be used to join the child thread. If the child thread
308 /// panics, `join` will return an `Err` containing the argument given to
313 /// Panics if the OS fails to create a thread; use `Builder::spawn`
314 /// to recover from such errors.
315 #[stable(feature = "rust1", since = "1.0.0")]
316 pub fn spawn<F, T>(f: F) -> JoinHandle<T> where
317 F: FnOnce() -> T, F: Send + 'static, T: Send + 'static
319 Builder::new().spawn(f).unwrap()
322 /// Gets a handle to the thread that invokes it.
326 /// Getting a handle to the current thread with `thread::current()`:
331 /// let handler = thread::Builder::new()
332 /// .name("named thread".into())
334 /// let handle = thread::current();
335 /// assert_eq!(handle.name(), Some("named thread"));
339 /// handler.join().unwrap();
341 #[stable(feature = "rust1", since = "1.0.0")]
342 pub fn current() -> Thread {
343 thread_info::current_thread().expect("use of std::thread::current() is not \
344 possible after the thread's local \
345 data has been destroyed")
348 /// Cooperatively gives up a timeslice to the OS scheduler.
349 #[stable(feature = "rust1", since = "1.0.0")]
351 imp::Thread::yield_now()
354 /// Determines whether the current thread is unwinding because of panic.
358 /// ```rust,should_panic
361 /// struct SomeStruct;
363 /// impl Drop for SomeStruct {
364 /// fn drop(&mut self) {
365 /// if thread::panicking() {
366 /// println!("dropped while unwinding");
368 /// println!("dropped while not unwinding");
375 /// let a = SomeStruct;
380 /// let b = SomeStruct;
385 #[stable(feature = "rust1", since = "1.0.0")]
386 pub fn panicking() -> bool {
387 panicking::panicking()
390 /// Puts the current thread to sleep for the specified amount of time.
392 /// The thread may sleep longer than the duration specified due to scheduling
393 /// specifics or platform-dependent functionality. Note that on unix platforms
394 /// this function will not return early due to a signal being received or a
396 #[stable(feature = "rust1", since = "1.0.0")]
397 #[rustc_deprecated(since = "1.6.0", reason = "replaced by `std::thread::sleep`")]
398 pub fn sleep_ms(ms: u32) {
399 sleep(Duration::from_millis(ms as u64))
402 /// Puts the current thread to sleep for the specified amount of time.
404 /// The thread may sleep longer than the duration specified due to scheduling
405 /// specifics or platform-dependent functionality.
407 /// # Platform behavior
409 /// On Unix platforms this function will not return early due to a
410 /// signal being received or a spurious wakeup. Platforms which do not support
411 /// nanosecond precision for sleeping will have `dur` rounded up to the nearest
412 /// granularity of time they can sleep for.
417 /// use std::{thread, time};
419 /// let ten_millis = time::Duration::from_millis(10);
420 /// let now = time::Instant::now();
422 /// thread::sleep(ten_millis);
424 /// assert!(now.elapsed() >= ten_millis);
426 #[stable(feature = "thread_sleep", since = "1.4.0")]
427 pub fn sleep(dur: Duration) {
428 imp::Thread::sleep(dur)
431 /// Blocks unless or until the current thread's token is made available.
433 /// Every thread is equipped with some basic low-level blocking support, via
434 /// the `park()` function and the [`unpark()`][unpark] method. These can be
435 /// used as a more CPU-efficient implementation of a spinlock.
437 /// [unpark]: struct.Thread.html#method.unpark
439 /// The API is typically used by acquiring a handle to the current thread,
440 /// placing that handle in a shared data structure so that other threads can
441 /// find it, and then parking (in a loop with a check for the token actually
444 /// A call to `park` does not guarantee that the thread will remain parked
445 /// forever, and callers should be prepared for this possibility.
447 /// See the [module documentation][thread] for more detail.
449 /// [thread]: index.html
451 // The implementation currently uses the trivial strategy of a Mutex+Condvar
452 // with wakeup flag, which does not actually allow spurious wakeups. In the
453 // future, this will be implemented in a more efficient way, perhaps along the lines of
454 // http://cr.openjdk.java.net/~stefank/6989984.1/raw_files/new/src/os/linux/vm/os_linux.cpp
455 // or futuxes, and in either case may allow spurious wakeups.
456 #[stable(feature = "rust1", since = "1.0.0")]
458 let thread = current();
459 let mut guard = thread.inner.lock.lock().unwrap();
461 guard = thread.inner.cvar.wait(guard).unwrap();
466 /// Use [park_timeout].
468 /// Blocks unless or until the current thread's token is made available or
469 /// the specified duration has been reached (may wake spuriously).
471 /// The semantics of this function are equivalent to `park()` except that the
472 /// thread will be blocked for roughly no longer than `ms`. This method
473 /// should not be used for precise timing due to anomalies such as
474 /// preemption or platform differences that may not cause the maximum
475 /// amount of time waited to be precisely `ms` long.
477 /// See the [module documentation][thread] for more detail.
479 /// [thread]: index.html
480 /// [park_timeout]: fn.park_timeout.html
481 #[stable(feature = "rust1", since = "1.0.0")]
482 #[rustc_deprecated(since = "1.6.0", reason = "replaced by `std::thread::park_timeout`")]
483 pub fn park_timeout_ms(ms: u32) {
484 park_timeout(Duration::from_millis(ms as u64))
487 /// Blocks unless or until the current thread's token is made available or
488 /// the specified duration has been reached (may wake spuriously).
490 /// The semantics of this function are equivalent to `park()` except that the
491 /// thread will be blocked for roughly no longer than `dur`. This method
492 /// should not be used for precise timing due to anomalies such as
493 /// preemption or platform differences that may not cause the maximum
494 /// amount of time waited to be precisely `dur` long.
496 /// See the module doc for more detail.
498 /// # Platform behavior
500 /// Platforms which do not support nanosecond precision for sleeping will have
501 /// `dur` rounded up to the nearest granularity of time they can sleep for.
505 /// Waiting for the complete expiration of the timeout:
508 /// use std::thread::park_timeout;
509 /// use std::time::{Instant, Duration};
511 /// let timeout = Duration::from_secs(2);
512 /// let beginning_park = Instant::now();
513 /// park_timeout(timeout);
515 /// while beginning_park.elapsed() < timeout {
516 /// println!("restarting park_timeout after {:?}", beginning_park.elapsed());
517 /// let timeout = timeout - beginning_park.elapsed();
518 /// park_timeout(timeout);
521 #[stable(feature = "park_timeout", since = "1.4.0")]
522 pub fn park_timeout(dur: Duration) {
523 let thread = current();
524 let mut guard = thread.inner.lock.lock().unwrap();
526 let (g, _) = thread.inner.cvar.wait_timeout(guard, dur).unwrap();
532 ////////////////////////////////////////////////////////////////////////////////
534 ////////////////////////////////////////////////////////////////////////////////
536 /// The internal representation of a `Thread` handle
538 name: Option<CString>, // Guaranteed to be UTF-8
539 lock: Mutex<bool>, // true when there is a buffered unpark
544 #[stable(feature = "rust1", since = "1.0.0")]
545 /// A handle to a thread.
551 // Used only internally to construct a thread object without spawning
552 fn new(name: Option<String>) -> Thread {
553 let cname = name.map(|n| {
554 CString::new(n).expect("thread name may not contain interior null bytes")
557 inner: Arc::new(Inner {
559 lock: Mutex::new(false),
560 cvar: Condvar::new(),
565 /// Atomically makes the handle's token available if it is not already.
567 /// See the module doc for more detail.
568 #[stable(feature = "rust1", since = "1.0.0")]
569 pub fn unpark(&self) {
570 let mut guard = self.inner.lock.lock().unwrap();
573 self.inner.cvar.notify_one();
577 /// Gets the thread's name.
581 /// Threads by default have no name specified:
586 /// let builder = thread::Builder::new();
588 /// let handler = builder.spawn(|| {
589 /// assert!(thread::current().name().is_none());
592 /// handler.join().unwrap();
595 /// Thread with a specified name:
600 /// let builder = thread::Builder::new()
601 /// .name("foo".into());
603 /// let handler = builder.spawn(|| {
604 /// assert_eq!(thread::current().name(), Some("foo"))
607 /// handler.join().unwrap();
609 #[stable(feature = "rust1", since = "1.0.0")]
610 pub fn name(&self) -> Option<&str> {
611 self.cname().map(|s| unsafe { str::from_utf8_unchecked(s.to_bytes()) } )
614 fn cname(&self) -> Option<&CStr> {
615 self.inner.name.as_ref().map(|s| &**s)
619 #[stable(feature = "rust1", since = "1.0.0")]
620 impl fmt::Debug for Thread {
621 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
622 fmt::Debug::fmt(&self.name(), f)
626 // a hack to get around privacy restrictions
627 impl thread_info::NewThread for Thread {
628 fn new(name: Option<String>) -> Thread { Thread::new(name) }
631 ////////////////////////////////////////////////////////////////////////////////
633 ////////////////////////////////////////////////////////////////////////////////
635 /// Indicates the manner in which a thread exited.
637 /// A thread that completes without panicking is considered to exit successfully.
638 #[stable(feature = "rust1", since = "1.0.0")]
639 pub type Result<T> = ::result::Result<T, Box<Any + Send + 'static>>;
641 // This packet is used to communicate the return value between the child thread
642 // and the parent thread. Memory is shared through the `Arc` within and there's
643 // no need for a mutex here because synchronization happens with `join()` (the
644 // parent thread never reads this packet until the child has exited).
646 // This packet itself is then stored into a `JoinInner` which in turns is placed
647 // in `JoinHandle` and `JoinGuard`. Due to the usage of `UnsafeCell` we need to
648 // manually worry about impls like Send and Sync. The type `T` should
649 // already always be Send (otherwise the thread could not have been created) and
650 // this type is inherently Sync because no methods take &self. Regardless,
651 // however, we add inheriting impls for Send/Sync to this type to ensure it's
652 // Send/Sync and that future modifications will still appropriately classify it.
653 struct Packet<T>(Arc<UnsafeCell<Option<Result<T>>>>);
655 unsafe impl<T: Send> Send for Packet<T> {}
656 unsafe impl<T: Sync> Sync for Packet<T> {}
658 /// Inner representation for JoinHandle
659 struct JoinInner<T> {
660 native: Option<imp::Thread>,
665 impl<T> JoinInner<T> {
666 fn join(&mut self) -> Result<T> {
667 self.native.take().unwrap().join();
669 (*self.packet.0.get()).take().unwrap()
674 /// An owned permission to join on a thread (block on its termination).
676 /// A `JoinHandle` *detaches* the child thread when it is dropped.
678 /// Due to platform restrictions, it is not possible to `Clone` this
679 /// handle: the ability to join a child thread is a uniquely-owned
682 /// This `struct` is created by the [`thread::spawn`] function and the
683 /// [`thread::Builder::spawn`] method.
687 /// Creation from [`thread::spawn`]:
692 /// let join_handle: thread::JoinHandle<_> = thread::spawn(|| {
693 /// // some work here
697 /// Creation from [`thread::Builder::spawn`]:
702 /// let builder = thread::Builder::new();
704 /// let join_handle: thread::JoinHandle<_> = builder.spawn(|| {
705 /// // some work here
709 /// [`thread::spawn`]: fn.spawn.html
710 /// [`thread::Builder::spawn`]: struct.Builder.html#method.spawn
711 #[stable(feature = "rust1", since = "1.0.0")]
712 pub struct JoinHandle<T>(JoinInner<T>);
714 impl<T> JoinHandle<T> {
715 /// Extracts a handle to the underlying thread
716 #[stable(feature = "rust1", since = "1.0.0")]
717 pub fn thread(&self) -> &Thread {
721 /// Waits for the associated thread to finish.
723 /// If the child thread panics, `Err` is returned with the parameter given
725 #[stable(feature = "rust1", since = "1.0.0")]
726 pub fn join(mut self) -> Result<T> {
731 impl<T> AsInner<imp::Thread> for JoinHandle<T> {
732 fn as_inner(&self) -> &imp::Thread { self.0.native.as_ref().unwrap() }
735 impl<T> IntoInner<imp::Thread> for JoinHandle<T> {
736 fn into_inner(self) -> imp::Thread { self.0.native.unwrap() }
739 fn _assert_sync_and_send() {
740 fn _assert_both<T: Send + Sync>() {}
741 _assert_both::<JoinHandle<()>>();
742 _assert_both::<Thread>();
745 ////////////////////////////////////////////////////////////////////////////////
747 ////////////////////////////////////////////////////////////////////////////////
752 use sync::mpsc::{channel, Sender};
754 use super::{Builder};
759 // !!! These tests are dangerous. If something is buggy, they will hang, !!!
760 // !!! instead of exiting cleanly. This might wedge the buildbots. !!!
763 fn test_unnamed_thread() {
764 thread::spawn(move|| {
765 assert!(thread::current().name().is_none());
766 }).join().ok().unwrap();
770 fn test_named_thread() {
771 Builder::new().name("ada lovelace".to_string()).spawn(move|| {
772 assert!(thread::current().name().unwrap() == "ada lovelace".to_string());
773 }).unwrap().join().unwrap();
778 fn test_invalid_named_thread() {
779 let _ = Builder::new().name("ada l\0velace".to_string()).spawn(|| {});
783 fn test_run_basic() {
784 let (tx, rx) = channel();
785 thread::spawn(move|| {
786 tx.send(()).unwrap();
792 fn test_join_panic() {
793 match thread::spawn(move|| {
796 result::Result::Err(_) => (),
797 result::Result::Ok(()) => panic!()
802 fn test_spawn_sched() {
803 let (tx, rx) = channel();
805 fn f(i: i32, tx: Sender<()>) {
807 thread::spawn(move|| {
809 tx.send(()).unwrap();
821 fn test_spawn_sched_childs_on_default_sched() {
822 let (tx, rx) = channel();
824 thread::spawn(move|| {
825 thread::spawn(move|| {
826 tx.send(()).unwrap();
833 fn avoid_copying_the_body<F>(spawnfn: F) where F: FnOnce(Box<Fn() + Send>) {
834 let (tx, rx) = channel();
836 let x: Box<_> = box 1;
837 let x_in_parent = (&*x) as *const i32 as usize;
839 spawnfn(Box::new(move|| {
840 let x_in_child = (&*x) as *const i32 as usize;
841 tx.send(x_in_child).unwrap();
844 let x_in_child = rx.recv().unwrap();
845 assert_eq!(x_in_parent, x_in_child);
849 fn test_avoid_copying_the_body_spawn() {
850 avoid_copying_the_body(|v| {
851 thread::spawn(move || v());
856 fn test_avoid_copying_the_body_thread_spawn() {
857 avoid_copying_the_body(|f| {
858 thread::spawn(move|| {
865 fn test_avoid_copying_the_body_join() {
866 avoid_copying_the_body(|f| {
867 let _ = thread::spawn(move|| {
874 fn test_child_doesnt_ref_parent() {
875 // If the child refcounts the parent thread, this will stack overflow when
876 // climbing the thread tree to dereference each ancestor. (See #1789)
877 // (well, it would if the constant were 8000+ - I lowered it to be more
878 // valgrind-friendly. try this at home, instead..!)
879 const GENERATIONS: u32 = 16;
880 fn child_no(x: u32) -> Box<Fn() + Send> {
881 return Box::new(move|| {
883 thread::spawn(move|| child_no(x+1)());
887 thread::spawn(|| child_no(0)());
891 fn test_simple_newsched_spawn() {
892 thread::spawn(move || {});
896 fn test_try_panic_message_static_str() {
897 match thread::spawn(move|| {
898 panic!("static string");
901 type T = &'static str;
902 assert!(e.is::<T>());
903 assert_eq!(*e.downcast::<T>().unwrap(), "static string");
910 fn test_try_panic_message_owned_str() {
911 match thread::spawn(move|| {
912 panic!("owned string".to_string());
916 assert!(e.is::<T>());
917 assert_eq!(*e.downcast::<T>().unwrap(), "owned string".to_string());
924 fn test_try_panic_message_any() {
925 match thread::spawn(move|| {
926 panic!(box 413u16 as Box<Any + Send>);
929 type T = Box<Any + Send>;
930 assert!(e.is::<T>());
931 let any = e.downcast::<T>().unwrap();
932 assert!(any.is::<u16>());
933 assert_eq!(*any.downcast::<u16>().unwrap(), 413);
940 fn test_try_panic_message_unit_struct() {
943 match thread::spawn(move|| {
946 Err(ref e) if e.is::<Juju>() => {}
947 Err(_) | Ok(()) => panic!()
952 fn test_park_timeout_unpark_before() {
954 thread::current().unpark();
955 thread::park_timeout(Duration::from_millis(u32::MAX as u64));
960 fn test_park_timeout_unpark_not_called() {
962 thread::park_timeout(Duration::from_millis(10));
967 fn test_park_timeout_unpark_called_other_thread() {
969 let th = thread::current();
971 let _guard = thread::spawn(move || {
972 super::sleep(Duration::from_millis(50));
976 thread::park_timeout(Duration::from_millis(u32::MAX as u64));
981 fn sleep_ms_smoke() {
982 thread::sleep(Duration::from_millis(2));
985 // NOTE: the corresponding test for stderr is in run-pass/thread-stderr, due
986 // to the test harness apparently interfering with stderr configuration.