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Merged
merged 5 commits into from
Nov 18, 2025
+38 −12
Merged

Further macOS OpenMP tweaks #497

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edcb6fb
Plugin uses "$(SHLIB_OPENMP_CFLAGS)" on macOS too, simplifies opnemp
eddelbuettel Nov 13, 2025
99e405d
Silence whining on windows and limit it to legacy
eddelbuettel Nov 13, 2025
4c85a92
Generalize OpenMP setup under macos as suggested by @coatless
eddelbuettel Nov 13, 2025
e113120
Refinements from code review
eddelbuettel Nov 13, 2025
87508e8
Reword one DEFINE as discussed
eddelbuettel Nov 15, 2025
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11 changes: 11 additions & 0 deletions ChangeLog
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Original file line number Diff line number Diff line change
@@ -1,3 +1,14 @@
2025-11-13 Dirk Eddelbuettel <edd@debian.org>

* R/inline.R (inlineCxxPlugin): No longer special-case macOS for
OpenMP but rely on "$(SHLIB_OPENMP_CFLAGS)" as everywhere else

* inst/include/RcppArmadillo/config/RcppArmadilloConfigGenerated.h.in:
Refine macOS OpenMP detection, respect RCPPARMA_MACOS_DISABLE_OPENMP

* inst/include/RcppArmadillo/config/RcppArmadilloConfig.h:
ARMA_CRIPPLED_LAPACK is only defined if 'LEGACY' Armadillo selected

2025-11-04 Dirk Eddelbuettel <edd@debian.org>

* README.md: Minor edits
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5 changes: 2 additions & 3 deletions R/inline.R
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@@ -1,4 +1,4 @@
## Copyright (C) 2010 - 2024 Dirk Eddelbuettel, Romain Francois and Douglas Bates
## Copyright (C) 2010 - 2025 Dirk Eddelbuettel, Romain Francois and Douglas Bates
##
## This file is part of RcppArmadillo.
##
Expand All @@ -16,8 +16,7 @@
## along with RcppArmadillo. If not, see <http://www.gnu.org/licenses/>.

inlineCxxPlugin <- function(...) {
ismacos <- Sys.info()[["sysname"]] == "Darwin"
openmpflag <- if (ismacos) "" else "$(SHLIB_OPENMP_CFLAGS)"
openmpflag <- "$(SHLIB_OPENMP_CFLAGS)"
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@coatless coatless Nov 14, 2025

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Shouldn't this be SHLIB_OPENMP_CXXFLAGS instead?

Suggested change
openmpflag <- "$(SHLIB_OPENMP_CFLAGS)"
openmpflag <- "$(SHLIB_OPENMP_CXXFLAGS)"

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@eddelbuettel eddelbuettel Nov 15, 2025

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It does not matter in practice. There are three, they are always identical (?) and CRAN only complains if you use different ones between compiler and linker. I have long used the C variant for simplicity (though also probably not always).

edd@paul:~$ grep SHLIB_OPENMP_ /etc/R/Makeconf 
SHLIB_OPENMP_CFLAGS = -fopenmp
SHLIB_OPENMP_CXXFLAGS = -fopenmp
SHLIB_OPENMP_FFLAGS = -fopenmp
edd@paul:~$

plugin <- Rcpp::Rcpp.plugin.maker(include.before = "#include <RcppArmadillo.h>",
libs = paste(openmpflag, "$(LAPACK_LIBS) $(BLAS_LIBS) $(FLIBS)"),
package = "RcppArmadillo")
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13 changes: 9 additions & 4 deletions inst/include/RcppArmadillo/config/RcppArmadilloConfig.h
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// RcppArmadilloConfig.h: Rcpp/Armadillo glue
//
// Copyright (C) 2010 - 2022 Dirk Eddelbuettel, Romain Francois and Douglas Bates
// Copyright (C) 2016 - 2022 George G. Vega Yon
// Copyright (C) 2017 - 2022 Serguei Sokol
// Copyright (C) 2010 - 2025 Dirk Eddelbuettel, Romain Francois and Douglas Bates
// Copyright (C) 2016 - 2025 George G. Vega Yon
// Copyright (C) 2017 - 2025 Serguei Sokol
//
// This file is part of RcppArmadillo.
//
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// R can be built with its own Rlapack library, or use an external
// one. Only the latter has zgesdd, a complex-valued SVD using divide-and-conquer
// on Windows we do not assume ZGESDD
#define ARMA_CRIPPLED_LAPACK 1
//
// Update 2025-Nov: R now generally has good enough LAPACK/BLAS, and newer Arma
// versions whine so protecting this now for use with Armadillo older than 15.*
#if defined(ARMA_SELECTED_LEGACY_VERSION)
#define ARMA_CRIPPLED_LAPACK 1
#endif
// on Windows we can now assume OpenMP with Rtools / gcc 4.9.3
// note that performance is said to still be poor
// cf https://cran.r-project.org/doc/manuals/r-devel/R-admin.html#The-MinGW_002dw64-toolchain
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21 changes: 16 additions & 5 deletions inst/include/RcppArmadillo/config/RcppArmadilloConfigGenerated.h.in
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// RcppArmadilloGenerated.h: Autoconf-updated file for LAPACK and OpenMP choices
// RcppArmadilloConfigGenerated.h: Autoconf-updated file for LAPACK and OpenMP choices
//
// Copyright (C) 2013 - 2021 Dirk Eddelbuettel
// Copyright (C) 2013 - 2025 Dirk Eddelbuettel
// 2025 James J. Balamuta
//
// This file is part of RcppArmadillo.
//
Expand All @@ -21,9 +22,19 @@
#ifndef RcppArmadillo__RcppArmadilloConfigGenerated__h
#define RcppArmadillo__RcppArmadilloConfigGenerated__h

#ifndef ARMA_USE_OPENMP
// from configure test for OpenMP based on how R is configured, and whether g++ new enough
@ARMA_HAVE_OPENMP@
// macOS special case as discussed in https://github.com/RcppCore/RcppArmadillo/issues/493
#if !defined(ARMA_USE_OPENMP)
#if defined(__APPLE__) && defined(_OPENMP)
// User has OpenMP available, but check if they want it disabled
#ifndef RCPPARMA_MACOS_DISABLE_OPENMP
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@coatless coatless Nov 14, 2025

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Is the standard prefix RCPPARMA? Or should we go RCPPARMADILLO ?

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@eddelbuettel eddelbuettel Nov 15, 2025 •
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Good catch. Both better and more consistent. Will switch to long form.

(I think I followed your suggestion letter by letter though 😜 )

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@coatless coatless Nov 18, 2025

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@eddelbuettel I know. I couldn't remember what was settled on for the prefix though post legacy/current defines.

#define ARMA_USE_OPENMP 1
#else
#define ARMA_DONT_USE_OPENMP 1
#endif
#else
// from configure test for OpenMP based on how R is configured
@ARMA_HAVE_OPENMP@
#endif
#endif

#endif