CMake Cannot Find `boost_sml` Headers in ROS 2 Workspace

I am encountering an issue with building the franka_ign_ros2_control package in my ROS 2 workspace. The build process fails because CMake cannot find the boost_sml headers. boost_sml is a header-only library from Boost and does not provide its own CMake configuration files.

I am using:

Ubuntu 22.04
CMake Version: 11.10.2
ROS2: Humble
BOOST_LIB_VERSION: 1_74

Error Message

CMake Error at CMakeLists.txt:24 (find_package): By not providing "Findboost_sml.cmake" in CMAKE_MODULE_PATH this project has asked CMake to find a package configuration file provided by "boost_sml", but CMake did not find one.

Could not find a package configuration file provided by "boost_sml" with any of the following names: boost_smlConfig.cmake boost_sml-config.cmake Add the installation prefix of "boost_sml" to CMAKE_PREFIX_PATH or set "boost_sml_DIR" to a directory containing one of the above files. If "boost_sml" provides a separate development package or SDK, be sure it has been installed.

Current Setup

Location of boost_sml Headers:
- The sml.hpp file is located at /home/group/boost_sml/include/boost/sml.hpp.
Environment Variables:
- CMAKE_PREFIX_PATH includes /home/group/boost_sml and /home/group/franka_ros2_ws/cmake.
```
echo $CMAKE_PREFIX_PATH
/home/group/boost_sml:/home/group/franka_ros2_ws/cmake
```

Custom CMake Module:

Created Findboost_sml.cmake in /home/group/franka_ros2_ws/cmake with the following content:

# Findboost_sml.cmake
# Locate the header files for boost_sml
message(STATUS "CMAKE_PREFIX_PATH: ${CMAKE_PREFIX_PATH}")
find_path(boost_sml_INCLUDE_DIRS
NAMES boost/sml.hpp
PATHS ${CMAKE_PREFIX_PATH}
DOC "Path to the boost_sml header files"
)

if (boost_sml_INCLUDE_DIRS)
message(STATUS "Found boost_sml: ${boost_sml_INCLUDE_DIRS}")
else()
message(FATAL_ERROR "Could not find boost_sml")
endif()

# Set the include directories
set(boost_sml_INCLUDE_DIR ${boost_sml_INCLUDE_DIRS})

# Mark the targets
add_library(boost_sml INTERFACE)
target_include_directories(boost_sml INTERFACE ${boost_sml_INCLUDE_DIR})

CMakeLists.txt Configuration:

Modified CMakeLists.txt for franka_gazebo_bringup and franka_ign_ros2_control to include the custom module path and find boost_sml.

Example for franka_gazebo_bringup:

cmake_minimum_required(VERSION 3.5)
project(franka_gazebo_bringup)

set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "/home/group/franka_ros2_ws/cmake")

find_package(ament_cmake REQUIRED)
find_package(boost_sml REQUIRED)

# Install project launch files
install(
DIRECTORY
 launch config
DESTINATION share/${PROJECT_NAME}
)

if(BUILD_TESTING)
find_package(ament_lint_auto REQUIRED)
ament_lint_auto_find_test_dependencies()
endif()

ament_package()

Example for franka_ign_ros2_control:

cmake_minimum_required(VERSION 3.5)
project(franka_ign_ros2_control)

set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "/home/group/franka_ros2_ws/cmake")

find_package(ament_cmake REQUIRED)
find_package(boost_sml REQUIRED)

# Other configuration and dependencies...

# Default to C11
if(NOT CMAKE_C_STANDARD)
 set(CMAKE_C_STANDARD 11)
endif()
# Default to C++17
if(NOT CMAKE_CXX_STANDARD)
 set(CMAKE_CXX_STANDARD 17)
endif()

# Compiler options
if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
 add_compile_options(-Wall -Wextra -Wpedantic)
endif()

# Find dependencies
find_package(ament_cmake REQUIRED)
find_package(ament_index_cpp REQUIRED)
find_package(controller_manager REQUIRED)
find_package(hardware_interface REQUIRED)
find_package(pluginlib REQUIRED)
find_package(rclcpp REQUIRED)
find_package(yaml_cpp_vendor REQUIRED)
find_package(franka_hardware REQUIRED)
find_package(urdf REQUIRED)
find_package(kdl_parser REQUIRED)
find_package(Franka 0.13.3 REQUIRED)
find_package(tf2_geometry_msgs REQUIRED)
find_package(tf2_eigen REQUIRED)

# Ignition versions
if("$ENV{IGNITION_VERSION}" STREQUAL "citadel")
find_package(ignition-gazebo3 REQUIRED)
set(IGN_GAZEBO_VER ${ignition-gazebo3_VERSION_MAJOR})
message(STATUS "Compiling against Ignition Citadel")
elseif("$ENV{IGNITION_VERSION}" STREQUAL "edifice")
find_package(ignition-gazebo5 REQUIRED)
set(IGN_GAZEBO_VER ${ignition-gazebo5_VERSION_MAJOR})
message(STATUS "Compiling against Ignition Edifice")
elseif("$ENV{IGNITION_VERSION}" STREQUAL "fortress")
find_package(ignition-gazebo6 REQUIRED)
set(IGN_GAZEBO_VER ${ignition-gazebo6_VERSION_MAJOR})
message(STATUS "Compiling against Ignition Fortress")
else()
find_package(ignition-gazebo6 REQUIRED)
set(IGN_GAZEBO_VER ${ignition-gazebo6_VERSION_MAJOR})
message(STATUS "Compiling against Ignition Fortress")
endif()

find_package(ignition-plugin1 REQUIRED)
set(IGN_PLUGIN_VER ${ignition-plugin1_VERSION_MAJOR})

include_directories(include)

add_library(${PROJECT_NAME}-system SHARED
src/ign_ros2_control_plugin.cpp
src/model_kdl.cpp
)

target_link_libraries(${PROJECT_NAME}-system
ignition-gazebo${IGN_GAZEBO_VER}::core
ignition-plugin${IGN_PLUGIN_VER}::register
)
ament_target_dependencies(${PROJECT_NAME}-system
ament_index_cpp
controller_manager
hardware_interface
pluginlib
rclcpp
yaml_cpp_vendor
rclcpp_lifecycle
franka_hardware
Franka
urdf
kdl_parser
tf2_geometry_msgs
tf2_eigen
)

add_library(ign_hardware_plugins SHARED
src/ign_system.cpp
src/model_kdl.cpp
)
ament_target_dependencies(ign_hardware_plugins
rclcpp_lifecycle
hardware_interface
rclcpp
franka_hardware
Franka
urdf
kdl_parser
tf2_geometry_msgs
tf2_eigen
)
target_link_libraries(ign_hardware_plugins
ignition-gazebo${IGN_GAZEBO_VER}::core
)

# Install
install(TARGETS
ign_hardware_plugins
ARCHIVE DESTINATION lib
LIBRARY DESTINATION lib
RUNTIME DESTINATION bin
)

install(DIRECTORY
include/
DESTINATION include
)

# Testing and linting
if(BUILD_TESTING)
find_package(ament_lint_auto REQUIRED)
ament_lint_auto_find_test_dependencies()
endif()

ament_export_include_directories(include)
ament_export_libraries(${PROJECT_NAME}-system ign_hardware_plugins)

install(TARGETS ${PROJECT_NAME}-system
DESTINATION lib
)

pluginlib_export_plugin_description_file(franka_ign_ros2_control ign_hardware_plugins.xml)

ament_package()

To address the issue, steps were taken to ensure that boost_sml was correctly installed and detected by CMake. First, I verified that the sml.hpp file was present in the directory /home/group/boost_sml/include/boost/sml.hpp, confirming that boost_sml was installed. Next, I set the CMAKE_PREFIX_PATH environment variable to include both /home/group/boost_sml and /home/group/franka_ros2_ws/cmake by running the command:


export CMAKE_PREFIX_PATH=/home/group/boost_sml:/home/group/franka_ros2_ws/cmake

To further diagnose the issue, I added debug output to the Findboost_sml.cmake file to print the CMAKE_PREFIX_PATH and to provide status messages about the search for boost_sml. The modified Findboost_sml.cmake file included the following lines:

message(STATUS "CMAKE_PREFIX_PATH: ${CMAKE_PREFIX_PATH}")
find_path(boost_sml_INCLUDE_DIRS
  NAMES boost/sml.hpp
  PATHS ${CMAKE_PREFIX_PATH}
  DOC "Path to the boost_sml header files"
)

if (boost_sml_INCLUDE_DIRS)
  message(STATUS "Found boost_sml: ${boost_sml_INCLUDE_DIRS}")
else()
  message(FATAL_ERROR "Could not find boost_sml")
endif()

After making these changes, I cleaned the workspace by deleting the build, install, and log directories to ensure a fresh build environment. I then attempted to rebuild the workspace using the following commands:

cd /home/group/franka_ros2_ws
rm -rf build install log
colcon build

Despite these efforts, the build process still fails with the same error. Could someone please advise on what might be missing or incorrect in my setup? Any help would be greatly appreciated.

Thank you!

frankaemika / franka_ros2