upgraded to C++20

Author: fbourgin

.github/workflows/linux.yml

@@ -96,7 +96,7 @@ jobs:
         if [[ "${{matrix.sys.compiler}}" = "gcc" ]]; then export CC=gcc-${{matrix.sys.version}}; export CXX=g++-${{matrix.sys.version}}; else export CC=clang; export CXX=clang++; fi
         mkdir ~/.R
         touch ~/.R/Makevars
-        echo "CXX17=$CXX" >> ~/.R/Makevars
-        echo "CXX17FLAGS=-fPIC -O2" >> ~/.R/Makevars
+        echo "CXX20=$CXX" >> ~/.R/Makevars
+        echo "CXX20FLAGS=-fPIC -O2" >> ~/.R/Makevars
         Rscript ./unittest.R
       

CMakeLists.txt

@@ -57,7 +57,7 @@ add_library(xtensor-r INTERFACE)
 target_include_directories(xtensor-r INTERFACE $<BUILD_INTERFACE:${XTENSOR_R_INCLUDE_DIR}>
                                                $<INSTALL_INTERFACE:include>)
 
-target_compile_features(xtensor-r INTERFACE cxx_std_17)
+target_compile_features(xtensor-r INTERFACE cxx_std_20)
 
 target_link_libraries(xtensor-r INTERFACE xtensor)
 get_target_property(inc_dir xtensor-r INTERFACE_INCLUDE_DIRECTORIES)

test/CMakeLists.txt

@@ -33,12 +33,12 @@ string(TOUPPER "${CMAKE_BUILD_TYPE}" U_CMAKE_BUILD_TYPE)
 
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "Intel")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native -Wunused-parameter -Wextra -Wreorder -Wconversion")
-    CHECK_CXX_COMPILER_FLAG("-std=c++17" HAS_CPP17_FLAG)
+    CHECK_CXX_COMPILER_FLAG("-std=c++20" HAS_CPP20_FLAG)
 
-    if (HAS_CPP17_FLAG)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17")
+    if (HAS_CPP20_FLAG)
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20")
     else()
-        message(FATAL_ERROR "Unsupported compiler -- xtensor requires C++17 support!")
+        message(FATAL_ERROR "Unsupported compiler -- xtensor requires C++20 support!")
     endif()
 endif()
 

test/rcpp_tests.cpp

@@ -7,7 +7,7 @@
 * The full license is in the file LICENSE, distributed with this software. *
 ****************************************************************************/
 
-// [[Rcpp::plugins(cpp17)]]
+// [[Rcpp::plugins(cpp20)]]
 // [[Rcpp::depends(xtensor)]]
 
 #include "xtensor-r/rcontainer.hpp"