Correcting CXX11 etc env vars for R 3.4.0 or later (closes #683)

ChangeLog

@@ -1,3 +1,11 @@
+2017-04-25  Dirk Eddelbuettel  <edd@debian.org>
+
+        * R/Attributes.R (.plugins[["cpp11"]]): If R 3.4.0 or newer is used, set
+        USE_CXX11 (instead of the older USE_CXX1X);
+        (.plugins[["cpp14"]]): similarly updated for C++14
+        (.plugins[["cpp17"]]): similarly updated for C++17
+        (.plugins[["cpp98"]]): added
+
 2017-04-22  Nathan Russell  <russell.nr2012@gmail.com>
 
         * inst/include/Rcpp/sugar/functions/strings/trimws.h: Added sugar

R/Attributes.R

@@ -1,5 +1,5 @@
 
-# Copyright (C) 2012 - 2016  JJ Allaire, Dirk Eddelbuettel and Romain Francois
+# Copyright (C) 2012 - 2017  JJ Allaire, Dirk Eddelbuettel and Romain Francois
 #
 # This file is part of Rcpp.
 #
@@ -456,9 +456,18 @@ compileAttributes <- function(pkgdir = ".", verbose = getOption("verbose")) {
 # setup plugins environment
 .plugins <- new.env()
 
-# built-in C++11 plugin
+# built-in C++98 plugin 
+.plugins[["cpp98"]] <- function() {
+    if (getRversion() >= "3.4")         # with recent R versions, R can decide
+        list(env = list(USE_CXX98 = "yes"))
+    else
+        list(env = list(PKG_CXXFLAGS ="-std=c++98"))
+}
+                                        # built-in C++11 plugin
 .plugins[["cpp11"]] <- function() {
-    if (getRversion() >= "3.1")         # with recent R versions, R can decide
+    if (getRversion() >= "3.4")         # with recent R versions, R can decide
+        list(env = list(USE_CXX11 = "yes"))
+    else if (getRversion() >= "3.1")    # with recent R versions, R can decide
         list(env = list(USE_CXX1X = "yes"))
     else if (.Platform$OS.type == "windows")
         list(env = list(PKG_CXXFLAGS = "-std=c++0x"))
@@ -475,7 +484,10 @@ compileAttributes <- function(pkgdir = ".", verbose = getOption("verbose")) {
 ## this is the default in g++-6.1 and later
 ## per https://gcc.gnu.org/projects/cxx-status.html#cxx14
 .plugins[["cpp14"]] <- function() {
-    list(env = list(PKG_CXXFLAGS ="-std=c++14"))
+    if (getRversion() >= "3.4")         # with recent R versions, R can decide
+        list(env = list(USE_CXX14 = "yes"))
+    else
+        list(env = list(PKG_CXXFLAGS ="-std=c++14"))
 }
 
 # built-in C++1y plugin for C++14 and C++17 standard under development
@@ -485,7 +497,10 @@ compileAttributes <- function(pkgdir = ".", verbose = getOption("verbose")) {
 
 # built-in C++17 plugin for C++17 standard (g++-6 or later)
 .plugins[["cpp17"]] <- function() {
-    list(env = list(PKG_CXXFLAGS ="-std=c++17"))
+    if (getRversion() >= "3.4")         # with recent R versions, R can decide
+        list(env = list(USE_CXX17 = "yes"))
+    else
+        list(env = list(PKG_CXXFLAGS ="-std=c++17"))
 }
 
 ## built-in C++1z plugin for C++17 standard under development

inst/NEWS.Rd

@@ -30,6 +30,12 @@
       \item Added sugar function \code{trimws} (Nathan Russell in \ghpr{680}
       addressing \ghit{679}).
     }
+    \item Changes in Rcpp Attributes:
+    \itemize{
+      \item The plugins for C++11, C++14, C++17 now set the values R 3.4.0 or
+      later expects; a plugin for C++98 was added (Dirk in \ghpr{684} addressing
+      \ghit{683}).
+    }
   }
 }
 
@@ -51,7 +57,7 @@
       \item The \code{algorithm.h} file now accomodates the Intel compiler
       (Dirk in \ghpr{643} and Dan in \ghpr{645} addressing issue \ghit{640}).
     }
-    \item Changes in Rcpp Attributes
+    \item Changes in Rcpp Attributes:
     \itemize{
       \item The C++17 standard is supported with a new plugin (used eg for
       \code{g++-6.2}).