How can I pass flags to R when it is compiling C++ code to be used in a package?

Question

I am trying to use some code from OpenCV in an R package, using Rcpp to build the package. When I compile the c code on my machine, it works fine.

For example, I am u

Answer 1

This is a Makevars file that actually worked for me:

PKG_LIBS = `pkg-config --libs opencv`
PKG_CFLAGS = `pkg-config --cflags opencv`
PKG_CXXFLAGS = `pkg-config --cflags opencv` `Rscript -e 'Rcpp:::CxxFlags()'`
PKG_CFLAGS = `pkg-config --cflags opencv`

Hope this helps.

Answer 2

You need to put a Makevars-File into your src directory and specify PKG_CPPFLAGS (preprocessor & includes) and PKG_CXXFLAGS (compiler flags). Details are in sections 1.2.1 and 5.5 in "Writing R Extensions".