RcppParallelLibs() example and CRAN

[evanbiederstedt]

Hi there

The example in the documentation for added RcppParallel to R packages is the following:

https://rcppcore.github.io/RcppParallel/#r_packages

src\Makevars

PKG_LIBS += $(shell ${R_HOME}/bin/Rscript -e "RcppParallel::RcppParallelLibs()")

src\Makevars.win

PKG_CXXFLAGS += -DRCPP_PARALLEL_USE_TBB=1

PKG_LIBS += $(shell "${R_HOME}/bin${R_ARCH_BIN}/Rscript.exe" \
              -e "RcppParallel::RcppParallelLibs()")

Question: is this CRAN compatible? The CRAN checks have been cracking down on += and ${shell .. } recently. GNU shell functions are not accepted.

https://cran.r-project.org/doc/manuals/R-exts.html#Writing-portable-packages

If the above is not CRAN-acceptable, would it be possible to provide new best standards to the community?

According to the manual:

The use of ${shell ...} can be avoided by using backticks, e.g.

PKG_CPPFLAGS = gsl-config --cflags
which works in all versions of make known74 to be used with R.

Thoughts?

Thanks for the help

[eddelbuettel]

The standard way around this to add GNU make as a SystemRequirement which is what the package does:

RcppParallel/DESCRIPTION

Line 32 in 5aa08f8

SystemRequirements: GNU make, Intel TBB, Windows: cmd.exe and cscript.exe, Solaris: g++ is required

See WRE -- this is the standard 'out' when one needs or wants a real make binary. There are other ways around it: you can also programmatically create src/Makevars from a src/Makevars.in by relying on a shell script, or R script, or .... saved as file configure (which does not have to be produced by autoconf).

[evanbiederstedt]

I understand now; apologies, I was confused. CRAN trauma, I suppose.

Thanks @eddelbuettel

[eddelbuettel]

No worries. We've all been there (see my now expanded comment for alternatives).