package lwt

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Condition variables to synchronize between threads.

type 'a t

Condition variable type. The type parameter denotes the type of value propagated from notifier to waiter.

val create : unit -> 'a t

create () creates a new condition variable.

val wait : ?mutex:Lwt_mutex.t -> 'a t -> 'a Lwt.t

wait mutex condvar will cause the current thread to block, awaiting notification for a condition variable, condvar. If provided, the mutex must have been previously locked (within the scope of Lwt_mutex.with_lock, for example) and is temporarily unlocked until the condition is notified. Upon notification, mutex is re-locked before wait returns and the thread's activity is resumed. When the awaited condition is notified, the value parameter passed to signal is returned.

val signal : 'a t -> 'a -> unit

signal condvar value notifies that a condition is ready. A single waiting thread will be awoken and will receive the notification value which will be returned from wait. Note that condition notification is not "sticky", i.e. if there is no waiter when signal is called, the notification will be missed and the value discarded.

val broadcast : 'a t -> 'a -> unit

broadcast condvar value notifies all waiting threads. Each will be awoken in turn and will receive the same notification value.

val broadcast_exn : 'a t -> exn -> unit

broadcast_exn condvar exn fails all waiting threads with exception exn.

  • since 2.6.0

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