[Rd] How can a package be aware of whether it's on CRAN

Henrik Bengtsson henr|k@bengt@@on @end|ng |rom gm@||@com
Tue Nov 23 22:08:35 CET 2021

On Tue, Nov 23, 2021 at 12:06 PM Gábor Csárdi <csardi.gabor using gmail.com> wrote:
> On Tue, Nov 23, 2021 at 8:49 PM Henrik Bengtsson
> <henrik.bengtsson using gmail.com> wrote:
> >
> > > Is there any reliable way to let packages to know if they are on CRAN, so they can set omp cores to 2 by default?
> >
> > Instead of testing for "on CRAN" or not, you can test for 'R CMD
> > check' running or not. 'R CMD check' sets environment variable
> > _R_CHECK_LIMIT_CORES_=TRUE. You can use that to limit your code to run
> > at most two (2) parallel threads or processes.
> AFAICT this is only set with --as-cran and many CRAN machines don't
> use that and I am fairly sure that some of them don't set this env var
> manually, either.

Oh my - yes & yes, especially on the second part - I totally forgot.
So, that alone is not sufficient. It's not meant to be easy, eh?

So, parallelly::availableCores() tries to account for this as well by
detecting that 'R CMD check' runs, cf.


> Gabor
> [...]

More information about the R-devel mailing list