BloombergLP::bslmt::Latch

Name

Description

Unnamed enum

Status codes for timed wait operations.

Name

Description

Latch [constructor]

Constructors

~Latch [destructor]

Destroy this latch. The behavior is undefined if any threads are waiting on this latch.

arrive

Decrement the number of events that this latch is waiting for by 1, and if the resulting number of events is 0 release any waiting threads. The behavior is undefined unless the sum of all events that have arrived at this latch does not exceed the count with which it was initialized. Note that the initial count of events is supplied at construction.

arriveAndWait

Decrement the number of events that this latch is waiting for by 1, and if the resulting number of events is 0 release any waiting threads; otherwise, block until the required number of events has been reached. The behavior is undefined unless the sum of all events that have arrived at this latch does not exceed the count with which it was initialized. Note that the initial count of events is supplied at construction. Also note that this method is equivalent to the following sequence: ` arrive(); wait(); `

clockType

Return the clock type used for timeouts.

countDown

Decrement the number of events that this latch is waiting for by the specified numEvents, and if the resulting number of events is 0 release any waiting threads. The behavior is undefined unless numEvents > 0 and the sum of all events that have arrived at this latch does not exceed the count with which it was initialized. Note that the initial count of events is supplied at construction.

currentCount

Return the current number of events for which this latch is waiting. Note that this method is provided primarily for debugging purposes (i.e., its intended use is not as a synchronization mechanism), and can be used only as an upper bound for the current count without other external state information.

timedWait

timedWait overloads

tryWait

Return true if this latch has already been released (i.e., the number of events the latch is waiting on is 0), and false otherwise. This method does not block. Note that a return value of true indicates a permanent state change (the latch has released and will never be un‐released), but a return value of false is ephemeral and cannot typically be acted upon without additional external state information. Also note that a return value of true does not guarantee this object is safe to destroy.

wait

Block until the number of events that this latch is waiting for reaches 0. Note that completion of this method does not guarantee this object is safe to destroy.