Take a look at https://github.com/ros2/demos/tree/ma... for a minimal example
cmake_minimum_required(VERSION 3.5)
project(pendulum_msgs)
# Default to C++14
if(NOT CMAKE_CXX_STANDARD)
set(CMAKE_CXX_STANDARD 14)
endif()
if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
add_compile_options(-Wall -Wextra -Wpedantic)
endif()
find_package(ament_cmake REQUIRED)
find_package(builtin_interfaces REQUIRED)
find_package(rosidl_default_generators REQUIRED)
rosidl_generate_interfaces(pendulum_msgs
"msg/JointState.msg"
"msg/JointCommand.msg"
"msg/RttestResults.msg"
DEPENDENCIES builtin_interfaces
)
ament_package()
and
<?xml version="1.0"?>
<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
<package format="3">
<name>pendulum_msgs</name>
<version>0.6.2</version>
<description>Custom messages for real-time pendulum control.</description>
<maintainer email="michael@openrobotics.org">Michael Carroll</maintainer>
<license>Apache License 2.0</license>
<author>Jackie Kay</author>
<author>Mikael Arguedas</author>
<buildtool_depend>ament_cmake</buildtool_depend>
<build_depend>builtin_interfaces</build_depend>
<build_depend>rosidl_default_generators</build_depend>
<exec_depend>builtin_interfaces</exec_depend>
<exec_depend>rosidl_default_runtime</exec_depend>
<member_of_group>rosidl_interface_packages</member_of_group>
<export>
<build_type>ament_cmake</build_type>
</export>
</package>