Miou_sync.Trigger
val create : unit -> t
create ()
allocates a new trigger in the initial state.
val is_initial : t -> bool
is_initial t
dtermines whether the trigger t
is in the initial state.
val is_signaled : t -> bool
is_signaled t
determines whether the trigger t
is in the signaled state.
val await : t -> (exn * Stdlib.Printexc.raw_backtrace) option
await t
waits for the trigger to be signal
ed.
The return value is None
in case the trigger was signaled before await
or we resumed the underlying continuation normally. Otherwise, the return value is Some (exn, bt)
, which indicates that the underlying continuation has been cancelled and the caller should raise the exception. In either case, the caller is responsible for cleaning up. Usually this means making sure that no references to the trigger remain to avoid space leak.
type Stdlib.Effect.t += private
| Await : t -> (exn * Stdlib.Printexc.raw_backtrace) option Stdlib.Effect.t
val signal : t -> unit
After signal t
returns, the trigger has been put into the signaled state and any attached action (via on_signal
) has been called.
Note that under normal circumstance, signal
should never raise an exception. If an exception is raised by signal
, it means that the attached action raised an error.
on_signal t x y fn
attempts to attach the fn
action to the trigger t
and transition the trigger to the awaiting state. It must be safe to call fn t x y
from any context that signal
might be called from.
The return value is true
in case the action was attached successfully. Otherwise, the return value is false
, which means that the trigger was already in the signaled state.