use C++ 20 in default. (#3187)

Signed-off-by: Tomoya.Fujita <fujita.tomoya@triorb.co.jp>
Signed-off-by: Alejandro Hernandez Cordero <ahcorde@gmail.com>
Co-authored-by: Alejandro Hernandez Cordero <ahcorde@gmail.com>

Author: fujitatomoya

rclcpp_action/CMakeLists.txt

@@ -3,18 +3,14 @@ cmake_minimum_required(VERSION 3.20)
 project(rclcpp_action)
 
 find_package(ament_cmake_ros REQUIRED)
+find_package(ament_cmake_ros_core REQUIRED)
 find_package(action_msgs REQUIRED)
 find_package(rclcpp REQUIRED)
 find_package(rcl REQUIRED)
 find_package(rcl_action REQUIRED)
 find_package(rcpputils REQUIRED)
 find_package(rosidl_runtime_c REQUIRED)
 
-# Default to C++17
-if(NOT CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 17)
-  set(CMAKE_CXX_STANDARD_REQUIRED ON)
-endif()
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   add_compile_options(
     -Wall -Wextra -Wpedantic -Wnon-virtual-dtor -Woverloaded-virtual
@@ -42,6 +38,9 @@ target_link_libraries(${PROJECT_NAME} PUBLIC
   rcl_action::rcl_action
   rclcpp::rclcpp
   rosidl_runtime_c::rosidl_runtime_c
+  # Note we link public on purpose, as we want to export
+  # the used C++ version as minimum to all consuming packages
+  ament_cmake_ros_core::ament_ros_defaults
 )
 target_link_libraries(${PROJECT_NAME} PRIVATE
   rcpputils::rcpputils

rclcpp_action/package.xml

@@ -18,6 +18,7 @@
 
   <build_export_depend>rosidl_runtime_c</build_export_depend>
 
+  <build_depend>ament_cmake_ros_core</build_depend>
   <build_depend>rosidl_runtime_c</build_depend>
 
   <depend>action_msgs</depend>

rclcpp_components/CMakeLists.txt

@@ -2,11 +2,6 @@ cmake_minimum_required(VERSION 3.20)
 
 project(rclcpp_components)
 
-# Default to C++17
-if(NOT CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 17)
-  set(CMAKE_CXX_STANDARD_REQUIRED ON)
-endif()
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   add_compile_options(
     -Wall -Wextra -Wpedantic -Wnon-virtual-dtor -Woverloaded-virtual
@@ -15,6 +10,7 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
 endif()
 
 find_package(ament_cmake_ros REQUIRED)
+find_package(ament_cmake_ros_core REQUIRED)
 find_package(ament_index_cpp REQUIRED)
 find_package(class_loader REQUIRED)
 find_package(composition_interfaces REQUIRED)
@@ -30,7 +26,10 @@ target_include_directories(component INTERFACE
   "$<INSTALL_INTERFACE:include/${PROJECT_NAME}>")
 target_link_libraries(component INTERFACE
   class_loader::class_loader
-  rclcpp::rclcpp)
+  rclcpp::rclcpp
+  # Note we link public on purpose, as we want to export
+  # the used C++ version as minimum to all consuming packages
+  ament_cmake_ros_core::ament_ros_defaults)
 
 add_library(
   component_manager
@@ -45,6 +44,9 @@ target_link_libraries(component_manager PUBLIC
   composition_interfaces::composition_interfaces
   rclcpp::rclcpp
   rmw::rmw
+  # Note we link public on purpose, as we want to export
+  # the used C++ version as minimum to all consuming packages
+  ament_cmake_ros_core::ament_ros_defaults
 )
 target_link_libraries(component_manager PRIVATE
   ament_index_cpp::ament_index_cpp

rclcpp_components/package.xml

@@ -22,6 +22,7 @@
   <build_export_depend>rcpputils</build_export_depend>
   <build_export_depend>rmw</build_export_depend>
 
+  <build_depend>ament_cmake_ros_core</build_depend>
   <build_depend>ament_index_cpp</build_depend>
   <build_depend>class_loader</build_depend>
   <build_depend>composition_interfaces</build_depend>

rclcpp_lifecycle/CMakeLists.txt

@@ -2,16 +2,12 @@ cmake_minimum_required(VERSION 3.20)
 
 project(rclcpp_lifecycle)
 
-# Default to C++17
-if(NOT CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 17)
-  set(CMAKE_CXX_STANDARD_REQUIRED ON)
-endif()
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   add_compile_options(-Wall -Wextra -Wpedantic -Wnon-virtual-dtor -Woverloaded-virtual)
 endif()
 
 find_package(ament_cmake_ros REQUIRED)
+find_package(ament_cmake_ros_core REQUIRED)
 find_package(lifecycle_msgs REQUIRED)
 find_package(rcl REQUIRED)
 find_package(rclcpp REQUIRED)
@@ -41,6 +37,9 @@ target_link_libraries(${PROJECT_NAME}
   rcl_lifecycle::rcl_lifecycle
   rcutils::rcutils
   rosidl_typesupport_cpp::rosidl_typesupport_cpp
+  # Note we link public on purpose, as we want to export
+  # the used C++ version as minimum to all consuming packages
+  ament_cmake_ros_core::ament_ros_defaults
 )
 
 # Causes the visibility macros to use dllexport rather than dllimport,

rclcpp_lifecycle/package.xml

@@ -16,6 +16,7 @@
 
   <buildtool_depend>ament_cmake_ros</buildtool_depend>
 
+  <build_depend>ament_cmake_ros_core</build_depend>
   <build_depend>lifecycle_msgs</build_depend>
   <build_depend>rcl</build_depend>
   <build_depend>rclcpp</build_depend>