[EXP] GH-44792: [C++] Require C++20

.github/workflows/cpp.yml

@@ -278,7 +278,7 @@ jobs:
         include:
           - os: windows-2019
             simd-level: AVX2
-            title: AMD64 Windows 2019 C++17 AVX2
+            title: AMD64 Windows 2019 C++20 AVX2
     env:
       ARROW_BOOST_USE_SHARED: OFF
       ARROW_BUILD_BENCHMARKS: ON
@@ -305,7 +305,7 @@ jobs:
       ARROW_WITH_ZLIB: ON
       ARROW_WITH_ZSTD: ON
       BOOST_SOURCE: BUNDLED
-      CMAKE_CXX_STANDARD: "17"
+      CMAKE_CXX_STANDARD: "20"
       CMAKE_GENERATOR: Ninja
       CMAKE_INSTALL_LIBDIR: bin
       CMAKE_INSTALL_PREFIX: /usr

.github/workflows/ruby.yml

@@ -353,7 +353,7 @@ jobs:
       ARROW_WITH_SNAPPY: ON
       ARROW_WITH_ZLIB: ON
       ARROW_WITH_ZSTD: ON
-      CMAKE_CXX_STANDARD: "17"
+      CMAKE_CXX_STANDARD: "20"
       CMAKE_GENERATOR: Ninja
       CMAKE_INSTALL_PREFIX: "${{ github.workspace }}/dist"
       CMAKE_UNITY_BUILD: ON

c_glib/meson.build

@@ -20,7 +20,7 @@
 project('arrow-glib', 'c', 'cpp',
         default_options: [
           'c_std=c99',
-          'cpp_std=c++17',
+          'cpp_std=c++20',
         ],
         license: 'Apache-2.0',
         # Debian:

ci/appveyor-cpp-build.bat

@@ -93,7 +93,7 @@ cmake -G "%GENERATOR%" %ARROW_CMAKE_ARGS% ^
       -DARROW_WITH_ZSTD=ON ^
       -DCMAKE_BUILD_TYPE="Release" ^
       -DCMAKE_CXX_FLAGS_RELEASE="/MD /Od /UNDEBUG" ^
-      -DCMAKE_CXX_STANDARD=17 ^
+      -DCMAKE_CXX_STANDARD=20 ^
       -DCMAKE_INSTALL_PREFIX=%CONDA_PREFIX%\Library ^
       -DCMAKE_UNITY_BUILD=ON ^
       -DCMAKE_VERBOSE_MAKEFILE=OFF ^

ci/scripts/cpp_build.sh

@@ -125,7 +125,7 @@ if [ "${ARROW_EMSCRIPTEN:-OFF}" = "ON" ]; then
     -DCMAKE_VERBOSE_MAKEFILE=${CMAKE_VERBOSE_MAKEFILE:-OFF} \
     -DCMAKE_C_FLAGS="${CFLAGS:-}" \
     -DCMAKE_CXX_FLAGS="${CXXFLAGS:-}" \
-    -DCMAKE_CXX_STANDARD="${CMAKE_CXX_STANDARD:-17}" \
+    -DCMAKE_CXX_STANDARD="${CMAKE_CXX_STANDARD:-20}" \
     -DCMAKE_INSTALL_LIBDIR=${CMAKE_INSTALL_LIBDIR:-lib} \
     -DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX:-${ARROW_HOME}} \
     -DCMAKE_UNITY_BUILD=${CMAKE_UNITY_BUILD:-OFF} \
@@ -216,7 +216,7 @@ else
     -DCMAKE_VERBOSE_MAKEFILE=${CMAKE_VERBOSE_MAKEFILE:-OFF} \
     -DCMAKE_C_FLAGS="${CFLAGS:-}" \
     -DCMAKE_CXX_FLAGS="${CXXFLAGS:-}" \
-    -DCMAKE_CXX_STANDARD="${CMAKE_CXX_STANDARD:-17}" \
+    -DCMAKE_CXX_STANDARD="${CMAKE_CXX_STANDARD:-20}" \
     -DCMAKE_INSTALL_LIBDIR=${CMAKE_INSTALL_LIBDIR:-lib} \
     -DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX:-${ARROW_HOME}} \
     -DCMAKE_UNITY_BUILD=${CMAKE_UNITY_BUILD:-OFF} \

cpp/CMakeLists.txt

@@ -553,10 +553,10 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${ARROW_CXXFLAGS}")
 # C++ specific flags.
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${CXX_COMMON_FLAGS} ${ARROW_CXXFLAGS}")
 
-# Remove --std=c++17 to avoid errors from C compilers
-string(REPLACE "-std=c++17" "" CMAKE_C_FLAGS ${CMAKE_C_FLAGS})
+# Remove -std=c++20 to avoid errors from C compilers
+string(REPLACE "-std=c++20" "" CMAKE_C_FLAGS ${CMAKE_C_FLAGS})
 
-# Add C++-only flags, like -std=c++17
+# Add C++-only flags, like -std=c++20
 set(CMAKE_CXX_FLAGS "${CXX_ONLY_FLAGS} ${CMAKE_CXX_FLAGS}")
 
 # ASAN / TSAN / UBSAN

cpp/cmake_modules/GandivaAddBitcode.cmake

@@ -17,7 +17,7 @@
 
 # Create bitcode for the given source file.
 function(gandiva_add_bitcode SOURCE)
-  set(CLANG_OPTIONS -std=c++17)
+  set(CLANG_OPTIONS -std=c++20)
   if(MSVC)
     # "19.20" means that it's compatible with Visual Studio 16 2019.
     # We can update this to "19.30" when we dropped support for Visual

cpp/cmake_modules/SetupCxxFlags.cmake

@@ -137,12 +137,12 @@ endif()
 
 # This ensures that things like c++17 get passed correctly
 if(NOT DEFINED CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 17)
-elseif(${CMAKE_CXX_STANDARD} VERSION_LESS 17)
-  message(FATAL_ERROR "Cannot set a CMAKE_CXX_STANDARD smaller than 17")
+  set(CMAKE_CXX_STANDARD 20)
+elseif(${CMAKE_CXX_STANDARD} VERSION_LESS 20)
+  message(FATAL_ERROR "Cannot set a CMAKE_CXX_STANDARD smaller than 20")
 endif()
 
-# We require a C++17 compliant compiler
+# We require a C++20 compliant compiler
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 # ARROW-6848: Do not use GNU (or other CXX) extensions

cpp/examples/minimal_build/CMakeLists.txt

@@ -24,10 +24,10 @@ option(ARROW_LINK_SHARED "Link to the Arrow shared library" ON)
 find_package(Arrow REQUIRED)
 
 if(NOT DEFINED CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 17)
+  set(CMAKE_CXX_STANDARD 20)
 endif()
 
-# We require a C++17 compliant compiler
+# We require a C++20 compliant compiler
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 if(NOT CMAKE_BUILD_TYPE)

cpp/examples/minimal_build/run_static.sh

@@ -86,7 +86,7 @@ echo
 
 rm -rf $EXAMPLE_BUILD_DIR
 mkdir -p $EXAMPLE_BUILD_DIR
-${CXX:-c++} -std=c++17 \
+${CXX:-c++} -std=c++20 \
   -o $EXAMPLE_BUILD_DIR/arrow-example \
   $EXAMPLE_DIR/example.cc \
   $(PKG_CONFIG_PATH=$ARROW_BUILD_DIR/lib/pkgconfig \

cpp/examples/parquet/parquet_arrow/CMakeLists.txt

@@ -28,10 +28,10 @@ option(PARQUET_LINK_SHARED "Link to the Parquet shared library" ON)
 
 # This ensures that things like -std=gnu++... get passed correctly
 if(NOT DEFINED CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 17)
+  set(CMAKE_CXX_STANDARD 20)
 endif()
 
-# We require a C++17 compliant compiler
+# We require a C++20 compliant compiler
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 # Look for installed packages the system

cpp/examples/tutorial_examples/CMakeLists.txt

@@ -21,7 +21,7 @@ project(ArrowTutorialExamples)
 
 find_package(ArrowDataset)
 
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror -Wall -Wextra")
 
 set(CMAKE_BUILD_TYPE Release)