Greetings and Salutations Jon, > Lack of OpenMP support in Apple’s build of Clang is cited as one reason for > not using it in CRAN builds
From R 3.4.x forward, OpenMP has been enabled in CRAN builds as the toolchain is using a custom compiler. You can see this with regard to the work done to enable OpenMP with RcppArmadillo with a configure script to detect the compiler: https://github.com/RcppCore/RcppArmadillo/pull/170 https://github.com/RcppCore/RcppArmadillo/pull/219 > but this is only partly true: after installing libomp ***from Homebrew***, I > have been adding Unfortunately, both Xcode and Xcode CLI do not ship clang with support for OpenMP. By installing `libomp` from homebrew, the system is getting a clang-compliant OpenMP compiler from the llvm formula. To check, please see: which clang I wish it were the case though... Sincerely, JJB On 6/6/19, 5:43 AM, "R-SIG-Mac on behalf of Jon Clayden" <r-sig-mac-boun...@r-project.org on behalf of jon.clay...@gmail.com> wrote: Dear all, Lack of OpenMP support in Apple’s build of Clang is cited as one reason for not using it in CRAN builds, but this is only partly true: after installing libomp from Homebrew, I have been adding “-Wp,-fopenmp” to CXXFLAGS and CFLAGS (and “-lomp” to LIBS) to my builds for a while, and everything seems to work OK. I’m not sure how far back this support goes (and I haven’t tried the Xcode 11 tools yet), but is there any known reason not to take this approach, and if not, would it make sense for R’s configure script to try “-Wp,-fopenmp” when testing for OpenMP support? All the best, Jon _______________________________________________ R-SIG-Mac mailing list R-SIG-Mac@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-mac _______________________________________________ R-SIG-Mac mailing list R-SIG-Mac@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-mac
