ROS Resources: Documentation | Support | Discussion Forum | Index | Service Status | ros @ Robotics Stack Exchange
Ask Your Question
1

ROS2 Conventions on installing headers

asked 2022-03-10 11:05:04 -0500

HorstLocal gravatar image

Hello,

I was wondering what is the convention on installing header from a ros2 component, as I noticed that quite a few components install into include/${PACKAGE_NAME}/${PACKAGE_NAME}/SomeHeader.hpp, while I would have expected include/${PROJECT_NAME}/SomeHeader.hpp, as it seems all Messages are and some packages like tf2 does it.

To me, the doubling in the path has to be a mistake, but then, so many packages do it. But the docs also seem to suggest single ${PROJECT_NAME}

Any hints welcome.

Thanks and Regards, Matthias

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted
0

answered 2023-03-08 12:07:31 -0500

clalancette gravatar image

To me, the doubling in the path has to be a mistake, but then, so many packages do it.

No, it's not a mistake, it is done that way on purpose. In particular, it is done that way so that the underlay/overlay functionality works properly.

As one example, assume you don't have the double-directory. Also assume you have Humble installed to /opt/ros/humble , and you have the packages ros-humble-foo and ros-humble-bar installed. In that case, the include files are /opt/ros/humble/include/foo/header.hpp and /opt/ros/humble/include/bar/header.hpp . Further, let's say that you include header files from both projects foo and bar, like:

#include foo/header.hpp
#include bar/header.hpp

And then you have in your CMakeLists.txt the following:

find_package(foo REQUIRED)

In this case, things will actually compile correctly, because the find_package foo added in the include directory like -I/opt/ros/humble/include. But that's not correct; the find_package(bar REQUIRED)is missing. This is one pretty trivial example, but there are a lot more of these problems that pop up, and the solution we used is to add the extra directory. You can see a lot more about the development of this and the problems that you might face at https://github.com/ros2/ros2/issues/1150 and https://colcon.readthedocs.io/en/rele...

All of that said, we only ever had time to make these fixes to the core packages; a lot of the community packages don't have this fix, even though they should. That will probably take quite a while to fix.

But the docs also seem to suggest single ${PROJECT_NAME}

This is a bug. Can you point out where that is, and/or make a PR to fix that?

edit flag offensive delete link more

Question Tools

1 follower

Stats

Asked: 2022-03-10 11:05:04 -0500

Seen: 63 times

Last updated: Mar 08 '23