package lwt

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Cooperative locks for mutual exclusion

type t

Type of Lwt mutexes

val create : unit -> t

create () creates a new mutex, which is initially unlocked

val lock : t -> unit Lwt.t

lock mutex lockcs the mutex, that is:

  • if the mutex is unlocked, then it is marked as locked and lock returns immediately
  • if it is locked, then lock waits for all threads waiting on the mutex to terminate, then it resumes when the last one unlocks the mutex

Note: threads are woken up in the same order they try to lock the mutex

val unlock : t -> unit

unlock mutex unlock the mutex if no threads is waiting on it. Otherwise it will eventually removes the first one and resumes it.

val is_locked : t -> bool

locked mutex returns whether mutex is currently locked

val is_empty : t -> bool

is_empty mutex returns true if they are no thread waiting on the mutex, and false otherwise

val with_lock : t -> (unit -> 'a Lwt.t) -> 'a Lwt.t

with_lock lock f is used to lock a mutex within a block scope. The function f () is called with the mutex locked, and its result is returned from the call to with_lock. If an exception is raised from f, the mutex is also unlocked before the scope of with_lock is exited.


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