Thanks, that helped. However, a user with gcc < 4.7 will still get cryptic errors.
I had another idea: I created a file src/AAA_check_cpp11.cpp, checking the preprocessor directive “__cplusplus”, see https://github.com/mnwright/ranger/blob/master/ranger-r-package/ranger/src/AAA_check_cpp11.cpp <https://github.com/mnwright/ranger/blob/master/ranger-r-package/ranger/src/AAA_check_cpp11.cpp>. This isn’t beautiful, but the error message is better and it’s fine on CRAN. > On 16 Nov 2015, at 13:56, Dirk Eddelbuettel <e...@debian.org> wrote: > > > On 16 November 2015 at 13:07, Marvin Wright wrote: > | I would like to check for C++11 support in a package. The package requires > gcc >= 4.7 or clang >= 3.0. Windows is handled differently in Makevars.win. I > tried two approaches in Makevars so far, but both give warnings in CRAN > checks. > | > | Approach 1: > | ## Check for gcc >= 4.7 > | ifeq ($(shell basename $(CC)),gcc) > | GCC_VER := $(shell gcc -dumpversion) > | GCC_MAJOR := $(shell gcc -dumpversion | cut -f1-2 -d.) > | > | GCC_OK := $(shell echo $(GCC_MAJOR) \>= 4.7 | bc ) > | ifneq ($(GCC_OK),1) > | $(error Error: gcc >= 4.7 required, version $(GCC_VER) installed. Please > update gcc.) > | endif > | endif > | > | Works quite well but a warning in check —as-cran: > | > Found the following file(s) containing GNU extensions: > | > src/Makevars > | > Portable Makefiles do not use GNU extensions such as +=, :=, $(shell), > | > $(wildcard), ifeq ... endif. See section ‘Writing portable packages’ in > | > the ‘Writing R Extensions’ manual. > > Yup. One of the things I dislike the about current CRAN checks. GNU Make *is* > a standard, but we are not allowed to use it unless we use the GNUMakefile > name (which is ugly), or declare a 'SystemRequirements: GNU make'. > > So I would not use this. > > | Approach 2: > | Use std=c++11 flag instead of CXX_STD = CXX11, which should work on gcc > >=4.7 and throw an error on earlier versions. > | > | This time in check —as-cran: > | > Non-portable flags in variable 'PKG_CPPFLAGS': > | > -std=c++11 > > Obviously not good as it throws an error. > > | Any other ideas how to check? Or is one of the versions above OK on CRAN? > > Look eg at RcppTOML which includes/provides the cpptoml.h header which is > real C++11. There I just do (in DESCRIPTION) > > SystemRequirements: A C++11 compiler. Version 4.6.* of g++ (as currently in > Rtools) is insufficient; versions 4.8.*, 4.9.* or later will be fine. > > and (in src/Makevars) > > ## This is a C++11 package > CXX_STD = CXX11 > > Then CRAN takes care of things -- see the status at > > https://cran.rstudio.com/web/checks/check_results_RcppTOML.html > > which generally builds fine (and where I just noticed the Mavericks error -- > ick. Anybody with a Mavericks box who can help by poking around ?) > > Dirk > > -- > http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org [[alternative HTML version deleted]] ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
