[Rd] Can crc32() assume to be available at the C level?
Prof Brian Ripley
ripley at stats.ox.ac.uk
Tue Mar 1 15:57:11 CET 2005
On Tue, 1 Mar 2005, Dirk Eddelbuettel wrote:
> Antoine Lucas suggested extending my small digest package (which provides md5
> and sha-1 digests of R objects, which it are serialized if needed) with a
> crc32 function, and provided a fairly complete patch.
> We are now wondering if we should play it safe and bundle crc32.c (plus
> utils) in the digest sources (as I do with md5 and sha1), or if we can assume
> that crc32 is present on all R platforms thanks to zlib.
> Is that the case? If so, is it a good idea to use it even though it doesn't
> appear in the header files? Or should we package "our" copy?
It is present, but with --with-zlib options it could be in an external
library and hence not exported by R.bin/libR.so. So I don't think you can
rely on finding it.
Brian D. Ripley, ripley at 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)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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