




The function process-join waits until the process process dies, or timeout seconds passed.
If the process dies then process-join returns t. If the timeout passed it returns nil.
process-join can be used on dead processes, and in this case returns t immediately.
The effect of process-join is similar to
(mp:process-wait-with-timeout
"Waiting for process to die" timeout
#'(lambda (x)
(not (mp:process-alive-p x))) process )
but the call above may not return until the next time the scheduler runs, possibly causing a delay. In contrast process-join returns immediately when the process dies.
LispWorks User Guide and Reference Manual - 20 Sep 2017