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core.sync.condition
The condition module provides a primitive for synchronized condition
checking.
License:
Authors:
Sean Kelly
Source core/sync/condition.d
- class
Condition
; - This class represents a condition variable as conceived by C.A.R. Hoare. As per Mesa type monitors however, "signal" has been replaced with "notify" to indicate that control is not transferred to the waiter when a notification is sent.Examples:
import core.thread; import core.sync.mutex; import core.sync.semaphore; void testNotify() { auto mutex = new Mutex; auto condReady = new Condition( mutex ); auto semDone = new Semaphore; auto synLoop = new Object; int numWaiters = 10; int numTries = 10; int numReady = 0; int numTotal = 0; int numDone = 0; int numPost = 0; void waiter() { for ( int i = 0; i < numTries; ++i ) { synchronized( mutex ) { while ( numReady < 1 ) { condReady.wait(); } --numReady; ++numTotal; } synchronized( synLoop ) { ++numDone; } semDone.wait(); } } auto group = new ThreadGroup; for ( int i = 0; i < numWaiters; ++i ) group.create( &waiter ); for ( int i = 0; i < numTries; ++i ) { for ( int j = 0; j < numWaiters; ++j ) { synchronized( mutex ) { ++numReady; condReady.notify(); } } while ( true ) { synchronized( synLoop ) { if ( numDone >= numWaiters ) break; } Thread.yield(); } for ( int j = 0; j < numWaiters; ++j ) { semDone.notify(); } } group.joinAll(); assert( numTotal == numWaiters * numTries ); } void testNotifyAll() { auto mutex = new Mutex; auto condReady = new Condition( mutex ); int numWaiters = 10; int numReady = 0; int numDone = 0; bool alert = false; void waiter() { synchronized( mutex ) { ++numReady; while ( !alert ) condReady.wait(); ++numDone; } } auto group = new ThreadGroup; for ( int i = 0; i < numWaiters; ++i ) group.create( &waiter ); while ( true ) { synchronized( mutex ) { if ( numReady >= numWaiters ) { alert = true; condReady.notifyAll(); break; } } Thread.yield(); } group.joinAll(); assert( numReady == numWaiters && numDone == numWaiters ); } void testWaitTimeout() { auto mutex = new Mutex; auto condReady = new Condition( mutex ); bool waiting = false; bool alertedOne = true; bool alertedTwo = true; void waiter() { synchronized( mutex ) { waiting = true; // we never want to miss the notification (30s) alertedOne = condReady.wait( dur!"seconds"(30) ); // but we don't want to wait long for the timeout (10ms) alertedTwo = condReady.wait( dur!"msecs"(10) ); } } auto thread = new Thread( &waiter ); thread.start(); while ( true ) { synchronized( mutex ) { if ( waiting ) { condReady.notify(); break; } } Thread.yield(); } thread.join(); assert( waiting ); assert( alertedOne ); assert( !alertedTwo ); } testNotify(); testNotifyAll(); testWaitTimeout();
- nothrow @safe this(Mutex
m
);
shared nothrow @safe this(shared Mutexm
); - Initializes a condition object which is associated with the supplied mutex object.Parameters:
Mutex m
The mutex with which this condition will be associated. Throws:SyncError on error. - @property Mutex
mutex
();
shared @property shared(Mutex)mutex
(); - Gets the mutex associated with this condition.Returns:The mutex associated with this condition.
- void
wait
();
shared voidwait
();
voidwait
(this Q)(bool_unused_
)
if (is(Q == Condition) || is(Q == shared(Condition))); - Wait until notified.Throws:SyncError on error.
- bool
wait
(Durationval
);
shared boolwait
(Durationval
);
boolwait
(this Q)(Durationval
, bool_unused_
)
if (is(Q == Condition) || is(Q == shared(Condition))); - Suspends the calling thread until a notification occurs or until the supplied time period has elapsed.Parameters:
Duration val
The time to wait. In val must be non-negative.
Throws:SyncError on error.Returns:true if notified before the timeout and false if not. - void
notify
();
shared voidnotify
();
voidnotify
(this Q)(bool_unused_
)
if (is(Q == Condition) || is(Q == shared(Condition))); - Notifies one waiter.Throws:SyncError on error.
- void
notifyAll
();
shared voidnotifyAll
();
voidnotifyAll
(this Q)(bool_unused_
)
if (is(Q == Condition) || is(Q == shared(Condition))); - Notifies all waiters.Throws:SyncError on error.
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