error in running llply with .parallel = TRUE

[xi]

Dear list,

Im trying the new plyr in parallel, and used the example from the
release news:

x <- seq_len(20)
wait <- function(i) Sys.sleep(0.1)
system.time(llply(x, wait))
# user system elapsed
# 0.007 0.005 2.005
library(doMC)
registerDoMC(2)
system.time(llply(x, wait, .parallel = TRUE))

But instead of returning any result, the following message kept
printing on R console:

---------------------------------------------------------------------------------------------------------------------
The process has forked and you cannot use this CoreFoundation \
functionality safely. You MUST exec().
Break on __THE_PROCESS_HAS_FORKED_AND_YOU_CANNOT_USE_THIS_\
COREFOUNDATION_FUNCTIONALITY___YOU_MUST_EXEC__() to debug.
---------------------------------------------------------------------------------------------------------------------

It seems to be a mac issue; see: http://developer.apple.com/library/mac/#technotes/tn2005/tn2083.html
(search Listing 13)

Anyone had the same problem with the multicore packages? And any
solution? (Probably more of a question related to the multicore
packages... )

Many thanks!
Xi



# Attached the session info ( multicore_0.1-3 has the same issue)

> sessionInfo()
R version 2.12.0 (2010-10-15)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)

locale:
[1] C

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

other attached packages:
[1] SAGx_1.24.0 multtest_2.5.14 doMC_1.2.1 multicore_0.1-4
foreach_1.3.0
[6] codetools_0.2-2 iterators_1.0.3 Biobase_2.10.0 ggplot2_0.8.8
proto_0.3-8
[11] reshape_0.8.3 plyr_1.2.1

loaded via a namespace (and not attached):
[1] MASS_7.3-8 splines_2.12.0 survival_2.35-8 tools_2.12.0