On 06/11/2013 11:36, Duncan Murdoch wrote:
On 13-11-06 5:26 AM, Renaud Gaujoux wrote:
Hi,
it seems that the package hooks .onLoad and its C++ pendant
R_unload_mylib are actually not called when R quits, but only when
explicitly calling detach('package:mylib', unload = TRUE).
Maybe this is platform specific, I'm on Ubuntu 13.10 - R 3.0.2 (see
below).
No, this is by design. See ?setHook.
* is there a mechanism that a package can use to effectively do some
cleanup on standard exit, such as calling cleaning up routines of a
loaded third-party library? I tried .onDetach but it did not work
either.
Yes, you can set a finalizer. See ?reg.finalizer.
RODBC is one example.
* by curiosity, in what kind of practical situation would a user
want to call detach(..., unload = TRUE)?
An example is when you want a different version of a package. (That
might now work and probably will not if the package does not unload its
DLL.)
* is there a reason why the hooks are not called on quit?
They are slow to run, and are usually not needed. Finalizers handle the
rare cases where you really do need something to happen.
Or to put it another way, the OS will do most of the unloading when it
terminates the process, more efficiently than the process itself can.
That includes 'unloading' DLLs and freeing memory.
Duncan Murdoch
Thank you.
Bests,
Renaud
###
Sys.info()
sysname release
version
"Linux"
"3.11.0-12-generic" "#19-Ubuntu SMP Wed Oct 9 16:20:46 UTC 2013"
nodename
machine login
"XXXXX"
"x86_64" "renaud"
user
effective_user
"renaud"
"renaud"
sessionInfo()
R version 3.0.2 (2013-09-25)
Platform: x86_64-pc-linux-gnu (64-bit)
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
LC_MONETARY=en_US.UTF-8
[6] LC_MESSAGES=en_US.UTF-8 LC_PAPER=en_US.UTF-8 LC_NAME=C
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
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--
Brian D. Ripley, rip...@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
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