These activities enable asynchronous programming. send() broadcasts a signal or a list of signals. Arrivals can subscribe to signals and (optionally) assign a handler with trap(). Note that, while inside a batch, all the signals subscribed before entering the batch are ignored. Upon a signal reception, the arrival stops the current activity and executes the handler (if provided). Then, the execution returns to the activity following the point of the interruption. untrap() can be used to unsubscribe from signals. wait() blocks until a signal is received.

send(.trj, signals, delay = 0)

trap(.trj, signals, handler = NULL, interruptible = TRUE)

untrap(.trj, signals)

wait(.trj)

Arguments

.trj
the trajectory object.
signals
signal or list of signals, accepts either a string, a list of strings or a callable object (a function) which must return a string or a list of strings.
delay
optional timeout to trigger the signals, accepts either a numeric or a callable object (a function) which must return a numeric.
handler
optional trajectory object to handle a signal received.
interruptible
whether the handler can be interrupted by signals.

Value

Returns the trajectory object.

See also

renege_if