[Rd] Best way to determine if you're running 32 or 64 bit R on windows

[Prof Brian Ripley]

On Fri, 2 Jul 2010, Jeffrey Horner wrote:

> Hi,
>
> Is this sufficient?

Yes, if you want to know in R code.

> if (.Machine$sizeof.pointer==4){
>  cat('32\n')
> } else {
>  cat('64\n')
> }
>
> Or is it better to test something in R.version, say os?

Not 'os' (the OS is the same), but 'arch' changes.  Just as on a Mac 
or on Linux.

> I'd like to use this to specify appropriate linker arguments when
> building the RMySQL windows package.

If you mean *installing*  (R CMD INSTALL, not R CMD build) the 
documented way is to use the environment variable R_ARCH: there are 
also make variables available, e.g. WIN.  See 
http://www.stats.ox.ac.uk/~ripley/Win64/W64porting.html (which is 
linked from the appropriate manuals).

>
> Jeff
> -- 
> http://biostat.mc.vanderbilt.edu/JeffreyHorner
>
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>

-- 
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