[Rd] setTimeLimit sometimes fails to terminate idle call in R

[Jeroen Ooms]

I would like to use setTimeLimit to abort operations that are stuck
waiting (idle) after n seconds. Below a toy example in which Sys.sleep
is a placeholder call that is idle:

testlimit <- function(){
  setTimeLimit(elapsed=3, transient=TRUE);
  Sys.sleep(10);
}
system.time(testlimit());

However this is giving inconsistent results. On windows and in
r-studio server (linux) the call is correctly aborted after 3 seconds.
However, when I run this in a terminal session in either on linux or
osx, the timeout is not triggered until after Sys.sleep() returns and
the total script takes 10+ seconds to complete.

What causes this difference? Is there something I can set in my
terminal R session such that the time limit is triggered? I am using
Ubuntu 13.04 (x64), and osx 10.8. Below three videos to illustrate the
issue:

  [1]: http://www.youtube.com/watch?v=d1qxbp2W2mY&hd=1
  [2]: http://www.youtube.com/watch?v=S0r-O9er4kU&hd=1
  [3]: http://www.youtube.com/watch?v=2D7TgtXUa3o&hd=1

> sessionInfo()
R version 3.0.1 RC (2013-05-10 r62729)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
 [7] LC_PAPER=C                 LC_NAME=C
 [9] LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base