src/libstd/sync/condvar.rs - rust - Git at Google

 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.

 use prelude::v1::*;

 use sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT};
 use sync::poison::{self, LockResult};
 use sys_common::condvar as sys;
 use sys_common::mutex as sys_mutex;
 use time::Duration;
 use sync::{mutex, MutexGuard};

 /// A Condition Variable
 ///
 /// Condition variables represent the ability to block a thread such that it
 /// consumes no CPU time while waiting for an event to occur. Condition
 /// variables are typically associated with a boolean predicate (a condition)
 /// and a mutex. The predicate is always verified inside of the mutex before
 /// determining that thread must block.
 ///
 /// Functions in this module will block the current **thread** of execution and
 /// are bindings to system-provided condition variables where possible. Note
 /// that this module places one additional restriction over the system condition
 /// variables: each condvar can be used with precisely one mutex at runtime. Any
 /// attempt to use multiple mutexes on the same condition variable will result
 /// in a runtime panic. If this is not desired, then the unsafe primitives in
 /// `sys` do not have this restriction but may result in undefined behavior.
 ///
 /// # Example
 ///
 /// ```
 /// use std::sync::{Arc, Mutex, Condvar};
 /// use std::thread::Thread;
 ///
 /// let pair = Arc::new((Mutex::new(false), Condvar::new()));
 /// let pair2 = pair.clone();
 ///
 /// // Inside of our lock, spawn a new thread, and then wait for it to start
 /// Thread::spawn(move|| {
 ///     let &(ref lock, ref cvar) = &*pair2;
 ///     let mut started = lock.lock().unwrap();
 ///     *started = true;
 ///     cvar.notify_one();
 /// });
 ///
 /// // wait for the thread to start up
 /// let &(ref lock, ref cvar) = &*pair;
 /// let mut started = lock.lock().unwrap();
 /// while !*started {
 ///     started = cvar.wait(started).unwrap();
 /// }
 /// ```
 #[stable]
 pub struct Condvar { inner: Box<StaticCondvar> }

 unsafe impl Send for Condvar {}
 unsafe impl Sync for Condvar {}

 /// Statically allocated condition variables.
 ///
 /// This structure is identical to `Condvar` except that it is suitable for use
 /// in static initializers for other structures.
 ///
 /// # Example
 ///
 /// ```
 /// use std::sync::{StaticCondvar, CONDVAR_INIT};
 ///
 /// static CVAR: StaticCondvar = CONDVAR_INIT;
 /// ```
 #[unstable = "may be merged with Condvar in the future"]
 pub struct StaticCondvar {
     inner: sys::Condvar,
     mutex: AtomicUsize,
 }

 unsafe impl Send for StaticCondvar {}
 unsafe impl Sync for StaticCondvar {}

 /// Constant initializer for a statically allocated condition variable.
 #[unstable = "may be merged with Condvar in the future"]
 pub const CONDVAR_INIT: StaticCondvar = StaticCondvar {
     inner: sys::CONDVAR_INIT,
     mutex: ATOMIC_USIZE_INIT,
 };

 impl Condvar {
     /// Creates a new condition variable which is ready to be waited on and
     /// notified.
     #[stable]
     pub fn new() -> Condvar {
         Condvar {
             inner: box StaticCondvar {
                 inner: unsafe { sys::Condvar::new() },
                 mutex: AtomicUsize::new(0),
             }
         }
     }

     /// Block the current thread until this condition variable receives a
     /// notification.
     ///
     /// This function will atomically unlock the mutex specified (represented by
     /// `mutex_guard`) and block the current thread. This means that any calls
     /// to `notify_*()` which happen logically after the mutex is unlocked are
     /// candidates to wake this thread up. When this function call returns, the
     /// lock specified will have been re-acquired.
     ///
     /// Note that this function is susceptible to spurious wakeups. Condition
     /// variables normally have a boolean predicate associated with them, and
     /// the predicate must always be checked each time this function returns to
     /// protect against spurious wakeups.
     ///
     /// # Failure
     ///
     /// This function will return an error if the mutex being waited on is
     /// poisoned when this thread re-acquires the lock. For more information,
     /// see information about poisoning on the Mutex type.
     ///
     /// # Panics
     ///
     /// This function will `panic!()` if it is used with more than one mutex
     /// over time. Each condition variable is dynamically bound to exactly one
     /// mutex to ensure defined behavior across platforms. If this functionality
     /// is not desired, then unsafe primitives in `sys` are provided.
     #[stable]
     pub fn wait<'a, T>(&self, guard: MutexGuard<'a, T>)
                        -> LockResult<MutexGuard<'a, T>> {
         unsafe {
             let me: &'static Condvar = &*(self as *const _);
             me.inner.wait(guard)
         }
     }

     /// Wait on this condition variable for a notification, timing out after a
     /// specified duration.
     ///
     /// The semantics of this function are equivalent to `wait()` except that
     /// the thread will be blocked for roughly no longer than `dur`. This method
     /// should not be used for precise timing due to anomalies such as
     /// preemption or platform differences that may not cause the maximum amount
     /// of time waited to be precisely `dur`.
     ///
     /// If the wait timed out, then `false` will be returned. Otherwise if a
     /// notification was received then `true` will be returned.
     ///
     /// Like `wait`, the lock specified will be re-acquired when this function
     /// returns, regardless of whether the timeout elapsed or not.
     // Note that this method is *not* public, and this is quite intentional
     // because we're not quite sure about the semantics of relative vs absolute
     // durations or how the timing guarantees play into what the system APIs
     // provide. There are also additional concerns about the unix-specific
     // implementation which may need to be addressed.
     #[allow(dead_code)]
     fn wait_timeout<'a, T>(&self, guard: MutexGuard<'a, T>, dur: Duration)
                            -> LockResult<(MutexGuard<'a, T>, bool)> {
         unsafe {
             let me: &'static Condvar = &*(self as *const _);
             me.inner.wait_timeout(guard, dur)
         }
     }

     /// Wake up one blocked thread on this condvar.
     ///
     /// If there is a blocked thread on this condition variable, then it will
     /// be woken up from its call to `wait` or `wait_timeout`. Calls to
     /// `notify_one` are not buffered in any way.
     ///
     /// To wake up all threads, see `notify_one()`.
     #[stable]
     pub fn notify_one(&self) { unsafe { self.inner.inner.notify_one() } }

     /// Wake up all blocked threads on this condvar.
     ///
     /// This method will ensure that any current waiters on the condition
     /// variable are awoken. Calls to `notify_all()` are not buffered in any
     /// way.
     ///
     /// To wake up only one thread, see `notify_one()`.
     #[stable]
     pub fn notify_all(&self) { unsafe { self.inner.inner.notify_all() } }
 }

 #[stable]
 impl Drop for Condvar {
     fn drop(&mut self) {
         unsafe { self.inner.inner.destroy() }
     }
 }

 impl StaticCondvar {
     /// Block the current thread until this condition variable receives a
     /// notification.
     ///
     /// See `Condvar::wait`.
     #[unstable = "may be merged with Condvar in the future"]
     pub fn wait<'a, T>(&'static self, guard: MutexGuard<'a, T>)
                        -> LockResult<MutexGuard<'a, T>> {
         let poisoned = unsafe {
             let lock = mutex::guard_lock(&guard);
             self.verify(lock);
             self.inner.wait(lock);
             mutex::guard_poison(&guard).get()
         };
         if poisoned {
             Err(poison::new_poison_error(guard))
         } else {
             Ok(guard)
         }
     }

     /// Wait on this condition variable for a notification, timing out after a
     /// specified duration.
     ///
     /// See `Condvar::wait_timeout`.
     #[allow(dead_code)] // may want to stabilize this later, see wait_timeout above
     fn wait_timeout<'a, T>(&'static self, guard: MutexGuard<'a, T>, dur: Duration)
                            -> LockResult<(MutexGuard<'a, T>, bool)> {
         let (poisoned, success) = unsafe {
             let lock = mutex::guard_lock(&guard);
             self.verify(lock);
             let success = self.inner.wait_timeout(lock, dur);
             (mutex::guard_poison(&guard).get(), success)
         };
         if poisoned {
             Err(poison::new_poison_error((guard, success)))
         } else {
             Ok((guard, success))
         }
     }

     /// Wake up one blocked thread on this condvar.
     ///
     /// See `Condvar::notify_one`.
     #[unstable = "may be merged with Condvar in the future"]
     pub fn notify_one(&'static self) { unsafe { self.inner.notify_one() } }

     /// Wake up all blocked threads on this condvar.
     ///
     /// See `Condvar::notify_all`.
     #[unstable = "may be merged with Condvar in the future"]
     pub fn notify_all(&'static self) { unsafe { self.inner.notify_all() } }

     /// Deallocate all resources associated with this static condvar.
     ///
     /// This method is unsafe to call as there is no guarantee that there are no
     /// active users of the condvar, and this also doesn't prevent any future
     /// users of the condvar. This method is required to be called to not leak
     /// memory on all platforms.
     #[unstable = "may be merged with Condvar in the future"]
     pub unsafe fn destroy(&'static self) {
         self.inner.destroy()
     }

     fn verify(&self, mutex: &sys_mutex::Mutex) {
         let addr = mutex as *const _ as uint;
         match self.mutex.compare_and_swap(0, addr, Ordering::SeqCst) {
             // If we got out 0, then we have successfully bound the mutex to
             // this cvar.
             0 => {}

             // If we get out a value that's the same as `addr`, then someone
             // already beat us to the punch.
             n if n == addr => {}

             // Anything else and we're using more than one mutex on this cvar,
             // which is currently disallowed.
             _ => panic!("attempted to use a condition variable with two \
                          mutexes"),
         }
     }
 }

 #[cfg(test)]
 mod tests {
     use prelude::v1::*;

     use super::{StaticCondvar, CONDVAR_INIT};
     use sync::mpsc::channel;
     use sync::{StaticMutex, MUTEX_INIT, Condvar, Mutex, Arc};
     use thread::Thread;
     use time::Duration;

     #[test]
     fn smoke() {
         let c = Condvar::new();
         c.notify_one();
         c.notify_all();
     }

     #[test]
     fn static_smoke() {
         static C: StaticCondvar = CONDVAR_INIT;
         C.notify_one();
         C.notify_all();
         unsafe { C.destroy(); }
     }

     #[test]
     fn notify_one() {
         static C: StaticCondvar = CONDVAR_INIT;
         static M: StaticMutex = MUTEX_INIT;

         let g = M.lock().unwrap();
         let _t = Thread::spawn(move|| {
             let _g = M.lock().unwrap();
             C.notify_one();
         });
         let g = C.wait(g).unwrap();
         drop(g);
         unsafe { C.destroy(); M.destroy(); }
     }

     #[test]
     fn notify_all() {
         const N: uint = 10;

         let data = Arc::new((Mutex::new(0), Condvar::new()));
         let (tx, rx) = channel();
         for _ in range(0, N) {
             let data = data.clone();
             let tx = tx.clone();
             Thread::spawn(move|| {
                 let &(ref lock, ref cond) = &*data;
                 let mut cnt = lock.lock().unwrap();
                 *cnt += 1;
                 if *cnt == N {
                     tx.send(()).unwrap();
                 }
                 while *cnt != 0 {
                     cnt = cond.wait(cnt).unwrap();
                 }
                 tx.send(()).unwrap();
             });
         }
         drop(tx);

         let &(ref lock, ref cond) = &*data;
         rx.recv().unwrap();
         let mut cnt = lock.lock().unwrap();
         *cnt = 0;
         cond.notify_all();
         drop(cnt);

         for _ in range(0, N) {
             rx.recv().unwrap();
         }
     }

     #[test]
     fn wait_timeout() {
         static C: StaticCondvar = CONDVAR_INIT;
         static M: StaticMutex = MUTEX_INIT;

         let g = M.lock().unwrap();
         let (g, success) = C.wait_timeout(g, Duration::nanoseconds(1000)).unwrap();
         assert!(!success);
         let _t = Thread::spawn(move || {
             let _g = M.lock().unwrap();
             C.notify_one();
         });
         let (g, success) = C.wait_timeout(g, Duration::days(1)).unwrap();
         assert!(success);
         drop(g);
         unsafe { C.destroy(); M.destroy(); }
     }

     #[test]
     #[should_fail]
     fn two_mutexes() {
         static M1: StaticMutex = MUTEX_INIT;
         static M2: StaticMutex = MUTEX_INIT;
         static C: StaticCondvar = CONDVAR_INIT;

         let mut g = M1.lock().unwrap();
         let _t = Thread::spawn(move|| {
             let _g = M1.lock().unwrap();
             C.notify_one();
         });
         g = C.wait(g).unwrap();
         drop(g);

         let _ = C.wait(M2.lock().unwrap()).unwrap();
     }
 }
	// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
	// file at the top-level directory of this distribution and at
	// http://rust-lang.org/COPYRIGHT.
	//
	// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
	// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
	// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
	// option. This file may not be copied, modified, or distributed
	// except according to those terms.

	use prelude::v1::*;

	use sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT};
	use sync::poison::{self, LockResult};
	use sys_common::condvar as sys;
	use sys_common::mutex as sys_mutex;
	use time::Duration;
	use sync::{mutex, MutexGuard};

	/// A Condition Variable
	///
	/// Condition variables represent the ability to block a thread such that it
	/// consumes no CPU time while waiting for an event to occur. Condition
	/// variables are typically associated with a boolean predicate (a condition)
	/// and a mutex. The predicate is always verified inside of the mutex before
	/// determining that thread must block.
	///
	/// Functions in this module will block the current thread of execution and
	/// are bindings to system-provided condition variables where possible. Note
	/// that this module places one additional restriction over the system condition
	/// variables: each condvar can be used with precisely one mutex at runtime. Any
	/// attempt to use multiple mutexes on the same condition variable will result
	/// in a runtime panic. If this is not desired, then the unsafe primitives in
	/// `sys` do not have this restriction but may result in undefined behavior.
	///
	/// # Example
	///
	/// ```
	/// use std::sync::{Arc, Mutex, Condvar};
	/// use std::thread::Thread;
	///
	/// let pair = Arc::new((Mutex::new(false), Condvar::new()));
	/// let pair2 = pair.clone();
	///
	/// // Inside of our lock, spawn a new thread, and then wait for it to start
	/// Thread::spawn(move\|\| {
	/// let &(ref lock, ref cvar) = &*pair2;
	/// let mut started = lock.lock().unwrap();
	/// *started = true;
	/// cvar.notify_one();
	/// });
	///
	/// // wait for the thread to start up
	/// let &(ref lock, ref cvar) = &*pair;
	/// let mut started = lock.lock().unwrap();
	/// while !*started {
	/// started = cvar.wait(started).unwrap();
	/// }
	/// ```
	#[stable]
	pub struct Condvar { inner: Box<StaticCondvar> }

	unsafe impl Send for Condvar {}
	unsafe impl Sync for Condvar {}

	/// Statically allocated condition variables.
	///
	/// This structure is identical to `Condvar` except that it is suitable for use
	/// in static initializers for other structures.
	///
	/// # Example
	///
	/// ```
	/// use std::sync::{StaticCondvar, CONDVAR_INIT};
	///
	/// static CVAR: StaticCondvar = CONDVAR_INIT;
	/// ```
	#[unstable = "may be merged with Condvar in the future"]
	pub struct StaticCondvar {
	inner: sys::Condvar,
	mutex: AtomicUsize,
	}

	unsafe impl Send for StaticCondvar {}
	unsafe impl Sync for StaticCondvar {}

	/// Constant initializer for a statically allocated condition variable.
	#[unstable = "may be merged with Condvar in the future"]
	pub const CONDVAR_INIT: StaticCondvar = StaticCondvar {
	inner: sys::CONDVAR_INIT,
	mutex: ATOMIC_USIZE_INIT,
	};

	impl Condvar {
	/// Creates a new condition variable which is ready to be waited on and
	/// notified.
	#[stable]
	pub fn new() -> Condvar {
	Condvar {
	inner: box StaticCondvar {
	inner: unsafe { sys::Condvar::new() },
	mutex: AtomicUsize::new(0),
	}
	}
	}

	/// Block the current thread until this condition variable receives a
	/// notification.
	///
	/// This function will atomically unlock the mutex specified (represented by
	/// `mutex_guard`) and block the current thread. This means that any calls
	/// to `notify_*()` which happen logically after the mutex is unlocked are
	/// candidates to wake this thread up. When this function call returns, the
	/// lock specified will have been re-acquired.
	///
	/// Note that this function is susceptible to spurious wakeups. Condition
	/// variables normally have a boolean predicate associated with them, and
	/// the predicate must always be checked each time this function returns to
	/// protect against spurious wakeups.
	///
	/// # Failure
	///
	/// This function will return an error if the mutex being waited on is
	/// poisoned when this thread re-acquires the lock. For more information,
	/// see information about poisoning on the Mutex type.
	///
	/// # Panics
	///
	/// This function will `panic!()` if it is used with more than one mutex
	/// over time. Each condition variable is dynamically bound to exactly one
	/// mutex to ensure defined behavior across platforms. If this functionality
	/// is not desired, then unsafe primitives in `sys` are provided.
	#[stable]
	pub fn wait<'a, T>(&self, guard: MutexGuard<'a, T>)
	-> LockResult<MutexGuard<'a, T>> {
	unsafe {
	let me: &'static Condvar = &(self as const _);
	me.inner.wait(guard)
	}
	}

	/// Wait on this condition variable for a notification, timing out after a
	/// specified duration.
	///
	/// The semantics of this function are equivalent to `wait()` except that
	/// the thread will be blocked for roughly no longer than `dur`. This method
	/// should not be used for precise timing due to anomalies such as
	/// preemption or platform differences that may not cause the maximum amount
	/// of time waited to be precisely `dur`.
	///
	/// If the wait timed out, then `false` will be returned. Otherwise if a
	/// notification was received then `true` will be returned.
	///
	/// Like `wait`, the lock specified will be re-acquired when this function
	/// returns, regardless of whether the timeout elapsed or not.
	// Note that this method is not public, and this is quite intentional
	// because we're not quite sure about the semantics of relative vs absolute
	// durations or how the timing guarantees play into what the system APIs
	// provide. There are also additional concerns about the unix-specific
	// implementation which may need to be addressed.
	#[allow(dead_code)]
	fn wait_timeout<'a, T>(&self, guard: MutexGuard<'a, T>, dur: Duration)
	-> LockResult<(MutexGuard<'a, T>, bool)> {
	unsafe {
	let me: &'static Condvar = &(self as const _);
	me.inner.wait_timeout(guard, dur)
	}
	}

	/// Wake up one blocked thread on this condvar.
	///
	/// If there is a blocked thread on this condition variable, then it will
	/// be woken up from its call to `wait` or `wait_timeout`. Calls to
	/// `notify_one` are not buffered in any way.
	///
	/// To wake up all threads, see `notify_one()`.
	#[stable]
	pub fn notify_one(&self) { unsafe { self.inner.inner.notify_one() } }

	/// Wake up all blocked threads on this condvar.
	///
	/// This method will ensure that any current waiters on the condition
	/// variable are awoken. Calls to `notify_all()` are not buffered in any
	/// way.
	///
	/// To wake up only one thread, see `notify_one()`.
	#[stable]
	pub fn notify_all(&self) { unsafe { self.inner.inner.notify_all() } }
	}

	#[stable]
	impl Drop for Condvar {
	fn drop(&mut self) {
	unsafe { self.inner.inner.destroy() }
	}
	}

	impl StaticCondvar {
	/// Block the current thread until this condition variable receives a
	/// notification.
	///
	/// See `Condvar::wait`.
	#[unstable = "may be merged with Condvar in the future"]
	pub fn wait<'a, T>(&'static self, guard: MutexGuard<'a, T>)
	-> LockResult<MutexGuard<'a, T>> {
	let poisoned = unsafe {
	let lock = mutex::guard_lock(&guard);
	self.verify(lock);
	self.inner.wait(lock);
	mutex::guard_poison(&guard).get()
	};
	if poisoned {
	Err(poison::new_poison_error(guard))
	} else {
	Ok(guard)
	}
	}

	/// Wait on this condition variable for a notification, timing out after a
	/// specified duration.
	///
	/// See `Condvar::wait_timeout`.
	#[allow(dead_code)] // may want to stabilize this later, see wait_timeout above
	fn wait_timeout<'a, T>(&'static self, guard: MutexGuard<'a, T>, dur: Duration)
	-> LockResult<(MutexGuard<'a, T>, bool)> {
	let (poisoned, success) = unsafe {
	let lock = mutex::guard_lock(&guard);
	self.verify(lock);
	let success = self.inner.wait_timeout(lock, dur);
	(mutex::guard_poison(&guard).get(), success)
	};
	if poisoned {
	Err(poison::new_poison_error((guard, success)))
	} else {
	Ok((guard, success))
	}
	}

	/// Wake up one blocked thread on this condvar.
	///
	/// See `Condvar::notify_one`.
	#[unstable = "may be merged with Condvar in the future"]
	pub fn notify_one(&'static self) { unsafe { self.inner.notify_one() } }

	/// Wake up all blocked threads on this condvar.
	///
	/// See `Condvar::notify_all`.
	#[unstable = "may be merged with Condvar in the future"]
	pub fn notify_all(&'static self) { unsafe { self.inner.notify_all() } }

	/// Deallocate all resources associated with this static condvar.
	///
	/// This method is unsafe to call as there is no guarantee that there are no
	/// active users of the condvar, and this also doesn't prevent any future
	/// users of the condvar. This method is required to be called to not leak
	/// memory on all platforms.
	#[unstable = "may be merged with Condvar in the future"]
	pub unsafe fn destroy(&'static self) {
	self.inner.destroy()
	}

	fn verify(&self, mutex: &sys_mutex::Mutex) {
	let addr = mutex as *const _ as uint;
	match self.mutex.compare_and_swap(0, addr, Ordering::SeqCst) {
	// If we got out 0, then we have successfully bound the mutex to
	// this cvar.
	0 => {}

	// If we get out a value that's the same as `addr`, then someone
	// already beat us to the punch.
	n if n == addr => {}

	// Anything else and we're using more than one mutex on this cvar,
	// which is currently disallowed.
	_ => panic!("attempted to use a condition variable with two \
	mutexes"),
	}
	}
	}

	#[cfg(test)]
	mod tests {
	use prelude::v1::*;

	use super::{StaticCondvar, CONDVAR_INIT};
	use sync::mpsc::channel;
	use sync::{StaticMutex, MUTEX_INIT, Condvar, Mutex, Arc};
	use thread::Thread;
	use time::Duration;

	#[test]
	fn smoke() {
	let c = Condvar::new();
	c.notify_one();
	c.notify_all();
	}

	#[test]
	fn static_smoke() {
	static C: StaticCondvar = CONDVAR_INIT;
	C.notify_one();
	C.notify_all();
	unsafe { C.destroy(); }
	}

	#[test]
	fn notify_one() {
	static C: StaticCondvar = CONDVAR_INIT;
	static M: StaticMutex = MUTEX_INIT;

	let g = M.lock().unwrap();
	let _t = Thread::spawn(move\|\| {
	let _g = M.lock().unwrap();
	C.notify_one();
	});
	let g = C.wait(g).unwrap();
	drop(g);
	unsafe { C.destroy(); M.destroy(); }
	}

	#[test]
	fn notify_all() {
	const N: uint = 10;

	let data = Arc::new((Mutex::new(0), Condvar::new()));
	let (tx, rx) = channel();
	for _ in range(0, N) {
	let data = data.clone();
	let tx = tx.clone();
	Thread::spawn(move\|\| {
	let &(ref lock, ref cond) = &*data;
	let mut cnt = lock.lock().unwrap();
	*cnt += 1;
	if *cnt == N {
	tx.send(()).unwrap();
	}
	while *cnt != 0 {
	cnt = cond.wait(cnt).unwrap();
	}
	tx.send(()).unwrap();
	});
	}
	drop(tx);

	let &(ref lock, ref cond) = &*data;
	rx.recv().unwrap();
	let mut cnt = lock.lock().unwrap();
	*cnt = 0;
	cond.notify_all();
	drop(cnt);

	for _ in range(0, N) {
	rx.recv().unwrap();
	}
	}

	#[test]
	fn wait_timeout() {
	static C: StaticCondvar = CONDVAR_INIT;
	static M: StaticMutex = MUTEX_INIT;

	let g = M.lock().unwrap();
	let (g, success) = C.wait_timeout(g, Duration::nanoseconds(1000)).unwrap();
	assert!(!success);
	let _t = Thread::spawn(move \|\| {
	let _g = M.lock().unwrap();
	C.notify_one();
	});
	let (g, success) = C.wait_timeout(g, Duration::days(1)).unwrap();
	assert!(success);
	drop(g);
	unsafe { C.destroy(); M.destroy(); }
	}

	#[test]
	#[should_fail]
	fn two_mutexes() {
	static M1: StaticMutex = MUTEX_INIT;
	static M2: StaticMutex = MUTEX_INIT;
	static C: StaticCondvar = CONDVAR_INIT;

	let mut g = M1.lock().unwrap();
	let _t = Thread::spawn(move\|\| {
	let _g = M1.lock().unwrap();
	C.notify_one();
	});
	g = C.wait(g).unwrap();
	drop(g);

	let _ = C.wait(M2.lock().unwrap()).unwrap();
	}
	}