[][src]Struct sgx_tstd::sync::SgxCondvar

pub struct SgxCondvar { /* fields omitted */ }

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 a 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.

Methods

impl SgxCondvar[src]

pub fn new() -> SgxCondvar[src]

Creates a new condition variable which is ready to be waited on and notified.

pub fn wait<'a, T>(
    &self,
    guard: SgxMutexGuard<'a, T>
) -> LockResult<SgxMutexGuard<'a, T>>
[src]

Blocks the current thread until this condition variable receives a notification.

This function will atomically unlock the mutex specified (represented by guard) and block the current thread. This means that any calls to [notify_one] or [notify_all] 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.

Errors

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 [SgxMutex] 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.

pub fn wait_until<'a, T, F>(
    &self,
    guard: SgxMutexGuard<'a, T>,
    condition: F
) -> LockResult<SgxMutexGuard<'a, T>> where
    F: FnMut(&mut T) -> bool, 
[src]

Blocks the current thread until this condition variable receives a notification and the required condition is met. Spurious wakeups are ignored and this function will only return once the condition has been met.

This function will atomically unlock the mutex specified (represented by guard) and block the current thread. This means that any calls to [notify_one] or [notify_all] 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.

Errors

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.

pub fn wait_while<'a, T, F>(
    &self,
    guard: SgxMutexGuard<'a, T>,
    condition: F
) -> LockResult<SgxMutexGuard<'a, T>> where
    F: FnMut(&mut T) -> bool, 
[src]

Blocks the current thread until this condition variable receives a notification and the provided condition is false.

This function will atomically unlock the mutex specified (represented by guard) and block the current thread. This means that any calls to notify_one or notify_all 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.

Errors

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.

pub fn wait_timeout_ms<'a, T>(
    &self,
    guard: SgxMutexGuard<'a, T>,
    ms: u32
) -> LockResult<(SgxMutexGuard<'a, T>, bool)>
[src]

Waits 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 ms milliseconds. 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 ms.

Note that the best effort is made to ensure that the time waited is measured with a monotonic clock, and not affected by the changes made to the system time.

The returned boolean is false only if the timeout is known to have elapsed.

Like wait, the lock specified will be re-acquired when this function returns, regardless of whether the timeout elapsed or not.

pub fn wait_timeout<'a, T>(
    &self,
    guard: SgxMutexGuard<'a, T>,
    dur: Duration
) -> LockResult<(SgxMutexGuard<'a, T>, WaitTimeoutResult)>
[src]

Waits 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.

Note that the best effort is made to ensure that the time waited is measured with a monotonic clock, and not affected by the changes made to the system time. 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. Additionally, it is typically desirable for the timeout to not exceed some duration in spite of spurious wakes, thus the sleep-duration is decremented by the amount slept. Alternatively, use the wait_timeout_while method to wait with a timeout while a predicate is true.

The returned WaitTimeoutResult value indicates if the timeout is known to have elapsed.

Like wait, the lock specified will be re-acquired when this function returns, regardless of whether the timeout elapsed or not.

pub fn wait_timeout_until<'a, T, F>(
    &self,
    guard: SgxMutexGuard<'a, T>,
    dur: Duration,
    condition: F
) -> LockResult<(SgxMutexGuard<'a, T>, WaitTimeoutResult)> where
    F: FnMut(&mut T) -> bool, 
[src]

Waits on this condition variable for a notification, timing out after a specified duration. Spurious wakes will not cause this function to return.

The semantics of this function are equivalent to wait_until 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.

Note that the best effort is made to ensure that the time waited is measured with a monotonic clock, and not affected by the changes made to the system time.

The returned WaitTimeoutResult value indicates if the timeout is known to have elapsed without the condition being met.

Like wait_until, the lock specified will be re-acquired when this function returns, regardless of whether the timeout elapsed or not.

pub fn wait_timeout_while<'a, T, F>(
    &self,
    guard: SgxMutexGuard<'a, T>,
    dur: Duration,
    condition: F
) -> LockResult<(SgxMutexGuard<'a, T>, WaitTimeoutResult)> where
    F: FnMut(&mut T) -> bool, 
[src]

Waits on this condition variable for a notification, timing out after a specified duration.

The semantics of this function are equivalent to wait_while 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.

Note that the best effort is made to ensure that the time waited is measured with a monotonic clock, and not affected by the changes made to the system time.

The returned WaitTimeoutResult value indicates if the timeout is known to have elapsed without the condition being met.

Like wait_while, the lock specified will be re-acquired when this function returns, regardless of whether the timeout elapsed or not.

pub fn signal(&self)[src]

Wakes 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 [broadcast].

pub fn broadcast(&self)[src]

Wakes up all blocked threads on this condvar.

This method will ensure that any current waiters on the condition variable are awoken. Calls to broadcast() are not buffered in any way.

To wake up only one thread, see [signal].

pub fn notify_one(&self)[src]

pub fn notify_all(&self)[src]

Trait Implementations

impl Debug for SgxCondvar[src]

impl Default for SgxCondvar[src]

fn default() -> SgxCondvar[src]

Creates a Condvar which is ready to be waited on and notified.

impl Drop for SgxCondvar[src]

Auto Trait Implementations

impl !RefUnwindSafe for SgxCondvar

impl Send for SgxCondvar

impl Sync for SgxCondvar

impl Unpin for SgxCondvar

impl UnwindSafe for SgxCondvar

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized
[src]

impl<T> Borrow<T> for T where
    T: ?Sized
[src]

impl<T> BorrowMut<T> for T where
    T: ?Sized
[src]

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 
[src]

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 
[src]

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 
[src]

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.