Getting error while building ros2_control_demo_example_8 package.

[anubhav1772]

I am trying to build ros2_control_demo_example_8 package but getting below error:

--- stderr: ros2_control_demo_example_8                                                                                      
/home/anubhav1772/ros2_ws/src/example_8/hardware/rrbot_transmissions_system_position_only.cpp: In member function ‘virtual hardware_interface::CallbackReturn ros2_control_demo_example_8::RRBotTransmissionsSystemPositionOnlyHardware::on_init(const hardware_interface::HardwareInfo&)’:
/home/anubhav1772/ros2_ws/src/example_8/hardware/rrbot_transmissions_system_position_only.cpp:98:24: error: ‘const struct hardware_interface::JointInfo’ has no member named ‘state_interfaces’; did you mean ‘interfaces’?
   98 |       if (!(joint_info.state_interfaces.size() == 1 &&
      |                        ^~~~~~~~~~~~~~~~
      |                        interfaces
/home/anubhav1772/ros2_ws/src/example_8/hardware/rrbot_transmissions_system_position_only.cpp:99:24: error: ‘const struct hardware_interface::JointInfo’ has no member named ‘state_interfaces’; did you mean ‘interfaces’?
   99 |             joint_info.state_interfaces[0] == hardware_interface::HW_IF_POSITION &&
      |                        ^~~~~~~~~~~~~~~~
      |                        interfaces
/home/anubhav1772/ros2_ws/src/example_8/hardware/rrbot_transmissions_system_position_only.cpp:100:24: error: ‘const struct hardware_interface::JointInfo’ has no member named ‘command_interfaces’
  100 |             joint_info.command_interfaces.size() == 1 &&
      |                        ^~~~~~~~~~~~~~~~~~
/home/anubhav1772/ros2_ws/src/example_8/hardware/rrbot_transmissions_system_position_only.cpp:101:24: error: ‘const struct hardware_interface::JointInfo’ has no member named ‘command_interfaces’
  101 |             joint_info.command_interfaces[0] == hardware_interface::HW_IF_POSITION))
      |                        ^~~~~~~~~~~~~~~~~~
gmake[2]: *** [CMakeFiles/ros2_control_demo_example_8.dir/build.make:76: CMakeFiles/ros2_control_demo_example_8.dir/hardware/rrbot_transmissions_system_position_only.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:137: CMakeFiles/ros2_control_demo_example_8.dir/all] Error 2
gmake: *** [Makefile:146: all] Error 2

I already have ros-humble-hardware-interface installed, if that's the requirement.

Am I doing something wrong here? I really need some advice on this.

[bmagyar]

You are trying to build the master branch on Humble. Try the humble branch ;)

[anubhav1772]

@bmagyar I cloned the humble branch. I re-verified it by downloading it manually. Still getting the same error. I am able to build ros2_control_demo_example_1, ros2_control_demo_example_7 and ros2_control_demo_example_9 packages successfully. I want to try transmission interface, that's why I want to build example_8.

[anubhav1772]

As per the documentation, state_interfaces and command_interfaces are the members of JointInfo.

Also, the content of /opt/ros/humble/include/hardware_interface/hardware_info.hpp

/// Contains semantic info about a given joint loaded from URDF for a transmission
struct JointInfo
{
  std::string name;
  std::vector<std::string> state_interfaces;
  std::vector<std::string> command_interfaces;
  std::string role;
  double mechanical_reduction = 1.0;
  double offset = 0.0;
};

So, I shouldn't get these errors.

[anubhav1772]

I found the mistake. I had ros2_control package in my workspace which was definitely not cloned from humble branch. So, ros2_control_demo_example_8 must be referring to the hardware interface of that package instead of /opt/ros/humble/include/hardware_interface. Thanks!