From a1c209182d142fa896c8412c0f32343503d77955 Mon Sep 17 00:00:00 2001
From: Jiaming Yuan <jm.yuan@outlook.com>
Date: Mon, 27 Mar 2023 18:24:25 +0800
Subject: [PATCH] [backport] Update c++ requirement to 17 for the R package.
 (#8860) (#8983)

---
 R-package/DESCRIPTION      | 5 +++--
 R-package/configure        | 6 +++---
 R-package/configure.ac     | 6 +++---
 R-package/src/Makevars.in  | 2 +-
 R-package/src/Makevars.win | 2 +-
 5 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/R-package/DESCRIPTION b/R-package/DESCRIPTION
index 20c45c0ae..8f8b23d76 100644
--- a/R-package/DESCRIPTION
+++ b/R-package/DESCRIPTION
@@ -66,5 +66,6 @@ Imports:
     methods,
     data.table (>= 1.9.6),
     jsonlite (>= 1.0),
-RoxygenNote: 7.2.2
-SystemRequirements: GNU make, C++14
+RoxygenNote: 7.2.3
+Encoding: UTF-8
+SystemRequirements: GNU make, C++17
diff --git a/R-package/configure b/R-package/configure
index 6c157ca17..761f2cf19 100755
--- a/R-package/configure
+++ b/R-package/configure
@@ -2096,9 +2096,9 @@ if test -z "${R_HOME}"; then
   exit 1
 fi
 
-CXX14=`"${R_HOME}/bin/R" CMD config CXX14`
-CXX14STD=`"${R_HOME}/bin/R" CMD config CXX14STD`
-CXX="${CXX14} ${CXX14STD}"
+CXX17=`"${R_HOME}/bin/R" CMD config CXX17`
+CXX17STD=`"${R_HOME}/bin/R" CMD config CXX17STD`
+CXX="${CXX17} ${CXX17STD}"
 CXXFLAGS=`"${R_HOME}/bin/R" CMD config CXXFLAGS`
 
 CC=`"${R_HOME}/bin/R" CMD config CC`
diff --git a/R-package/configure.ac b/R-package/configure.ac
index 98dfd9782..f56303c7a 100644
--- a/R-package/configure.ac
+++ b/R-package/configure.ac
@@ -10,9 +10,9 @@ if test -z "${R_HOME}"; then
   exit 1
 fi
 
-CXX14=`"${R_HOME}/bin/R" CMD config CXX14`
-CXX14STD=`"${R_HOME}/bin/R" CMD config CXX14STD`
-CXX="${CXX14} ${CXX14STD}"
+CXX17=`"${R_HOME}/bin/R" CMD config CXX17`
+CXX17STD=`"${R_HOME}/bin/R" CMD config CXX17STD`
+CXX="${CXX17} ${CXX17STD}"
 CXXFLAGS=`"${R_HOME}/bin/R" CMD config CXXFLAGS`
 
 CC=`"${R_HOME}/bin/R" CMD config CC`
diff --git a/R-package/src/Makevars.in b/R-package/src/Makevars.in
index 9b2610638..6902b6c1d 100644
--- a/R-package/src/Makevars.in
+++ b/R-package/src/Makevars.in
@@ -3,7 +3,7 @@ PKGROOT=../../
 ENABLE_STD_THREAD=1
 # _*_ mode: Makefile; _*_
 
-CXX_STD = CXX14
+CXX_STD = CXX17
 
 XGB_RFLAGS = -DXGBOOST_STRICT_R_MODE=1 -DDMLC_LOG_BEFORE_THROW=0\
            -DDMLC_ENABLE_STD_THREAD=$(ENABLE_STD_THREAD) -DDMLC_DISABLE_STDIN=1\
diff --git a/R-package/src/Makevars.win b/R-package/src/Makevars.win
index 05399ad4d..4a209258d 100644
--- a/R-package/src/Makevars.win
+++ b/R-package/src/Makevars.win
@@ -3,7 +3,7 @@ PKGROOT=../../
 ENABLE_STD_THREAD=0
 # _*_ mode: Makefile; _*_
 
-CXX_STD = CXX14
+CXX_STD = CXX17
 
 XGB_RFLAGS = -DXGBOOST_STRICT_R_MODE=1 -DDMLC_LOG_BEFORE_THROW=0\
            -DDMLC_ENABLE_STD_THREAD=$(ENABLE_STD_THREAD) -DDMLC_DISABLE_STDIN=1\