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

[Gábor Csárdi]

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.

Gabor

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