Stops a ‘mirai’ if still in progress, causing it to resolve immediately to an ‘errorValue’ 20 (Operation canceled).
Value
Logical TRUE if the cancellation request was successful (was
awaiting execution or in execution), or else FALSE (if already
completed or previously cancelled). Will always return FALSE if not
using dispatcher.
Or a vector of logical values if supplying a list of ‘mirai’, such
as those returned by mirai_map.
Details
Using dispatcher allows cancellation of ‘mirai’. In the case that the ‘mirai’ is awaiting execution, it is discarded from the queue and never evaluated. In the case it is already in execution, an interrupt will be sent.
A successful cancellation request does not guarantee successful cancellation: the task, or a portion of it, may have already completed before the interrupt is received. Even then, compiled code is not always interruptible. This should be noted, particularly if the code carries out side effects during execution, such as writing to files, etc.
Examples
if (interactive()) {
# Only run examples in interactive R sessions
m <- mirai(Sys.sleep(n), n = 5)
stop_mirai(m)
m$data
}