On Jul 20, 2009, at 7:06 PM, Dan Kelley wrote:
I am trying to write a C function to create a vector of integers
that can be
used by the R calling function. I do not know the size of the
vector in the
R calling function. (Well, actually, I have an upper limit on the
size, but
that is so large that R cannot allocate it. What I'm doing in the
function
is to do a sieving procedure, and the result will be small enough to
fit
into my machine's memory.)
My reading of sections 6.1.1 and 6.1.2 of the guide on writing R
extensions
has left me a bit confused. Under R_alloc, I read "R will reclaim
the
memory at the end of the call" which seems to suggest the storage
won't be
made available afterwards, so that's not what I should use. As for
the
alterntaive, under Calloc, I read "This memory lasts until freed by
the
user", and it's clear that this is to be done within the C function in
question.
Summary question: how can I allocate memory withing a C function,
making it
available to an R function that calls the C function?
Thanks. Dan.
--
You might look at the package bigmemory to see how they attacked the
problem. In fact if my reading of their documentation is correct they
may have already done your work for you:
http://www.stat.yale.edu/~jay/bigmemory
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
