R Under development (unstable) (2024-07-26 r86926 ucrt) -- "Unsuffered Consequences"
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> if (getRversion() >= "4.4.0") {
+ 
+   library(parallelly)
+   library(parallel)
+   
+   cl <- makeClusterSequential()
+   print(cl)
+ 
+   y_truth <- lapply(X = 1:3, FUN = sqrt)
+   y <- parLapply(cl, X = 1:3, fun = sqrt)
+   str(y)
+   stopifnot(identical(y, y_truth))
+   
+   pid <- Sys.getpid()
+   print(pid)
+   y <- clusterEvalQ(cl, Sys.getpid())
+   str(y)
+   stopifnot(identical(y[[1]], pid))
+   
+   y <- clusterEvalQ(cl, { abc <- 42; abc })
+   str(y)
+   stopifnot(!exists("abc", inherits = FALSE))
+ 
+   stopCluster(cl)
+   print(cl)
+ 
+   res <- tryCatch({
+     y <- clusterEvalQ(cl, { 42 })
+   }, error = identity)
+   print(res)
+   stopifnot(inherits(res, "error"))
+ } ## if (getRversion() >= "4.4.0")
A 'sequential_cluster' cluster with 1 node
List of 3
 $ : num 1
 $ : num 1.41
 $ : num 1.73
[1] 71840
List of 1
 $ : int 71840
List of 1
 $ : num 42
A 'sequential_cluster' cluster with 1 node
<simpleError in sendData.sequential_node(con, list(type = type, data = value,     tag = tag)): The 'sequential_node' node is no longer valid, which suggests the cluster it belongs to has been stopped>
> 
> proc.time()
   user  system elapsed 
   0.23    0.10    0.32