Issue when exporting a new package with SOEM

[wongkaiweng]

Hi,

I am trying to set up a new package (pkg_a) that depends on SOEM. I got that working properly. The problem appears when I use this new package with another package (pkg_b), I have to add ${soem_INCLUDE_DIRS}/soem in the include_directories of pkg_b again.

I am looking to find a solution that this is taken care of in pkg_a. Since I cannot add ${soem_INCLUDE_DIRS}/soem in catkin_package INCLUDE_DIRS of pkg_a (I would get a non-package include path error from catkin_lint), I am curious if there is a way to do this.

Thanks!

[mgruhler]

Actually, exporting ${soem_INCLUDE_DIRS}/soem in pkg_a is the way that I was using it so far as well.

If your problem is "only" automated tests, you could "silence" catkin_lint by using the --ignore external_include_path flag. Though I'm not sure you'd want to do that, depending on your test setup.

What should work is to include soem not as a catkin package, but as a system package and export that in pkg_a. I.e. use the following snippets instead of the typical catkin-way to do things:

find_package(catkin REQUIRED ...)
find_package(soem REQUIRED)

catkin_package(
  ...
  DEPENDS
    soem
  ...
)

include_directories(
  ...
  ${soem_INCLUDE_DIRS}
  ${soem_INCLUDE_DIRS}/soem
)

target_link_libraries(${PROJECT_NAME} ${catkin_LIBRARIES} ${soem_LIBRARIES})

and then only find_package( catkin REQUIRED COMPONENTS pkg_a) in pkg_b.
A quick check in my repos (if I understood correctly, I am doing the same thing you do) seems to confirm this. If this does not work for you, please report back with a SSCCE.

Other than that, I'd like to link to #17 which when (if) a proper solution is available would also solve your issue.

[wongkaiweng]

Thank you for the suggestion. I tried it out and here are my observations:

1. find_package(soem REQUIRED) is problematic. catkin_make can pass the configuration step but it cannot find references to functions. Here's is an example of the errors: undefined reference to 'ec_SDOwrite'. However, if soem is in find_package(catkin REQUIRED COMPONENTS soem) for example, then it compiles without an issue.

2. Putting soem under DEPENDS in catkin_package didn't work for me and here's the error from catkin_lint: catkin_package() lists 'soem' as system package but it is not. I would like to avoid 'silencing' catkin_lint if possible. This is related to 1. probably.

I got the ROS version of SOEM. Could that be the reason why it is not a system package? I'm not sure how this is handled behind the scene. I will follow #17 too.

[mgruhler]

about 1: This seems to be a linker error. Did you add ${soem_LIBRARIES} to any target_link_libraries calls? This is all assuming you are actually using this in pkg_a.
If you call a soem function in pkg_b directly, you do have a direct dependency on soem and should thus add it to your pkg_b explicitly.
If both of the above are not the case, please describe your problem in more details with relevant code and a reproducible example.

about 2: I'm not sure how catkin_lint is actually deducing that soem is a catkin package in this case. I was assuming that it is taking all `find_package'd packages, but this seems to not be the case. However, I can reproduce your problem. And I don't have any immediate solution.

This package is a wrapped version of SOEM for the use with ROS. You could also try the original SOEM (linked in the description and the README), but will probably run into a lot of the same issues you are having here :-)
In the end, I hope to find a solution by fixing #17 and #16, but I still don't have a roadmap or even an estimation when and how this might be done.

As a last resort, I just learned that you can also ignore catkin_lint errors in a single package or even only for a single line by adding the pragmas #catkin_lint: ignore <ID> at the top of the file or #catkin_lint: ignore_once <ID> directly before the statement, as described here.

[mgruhler]

@wongkaiweng I just sent #23 which (among others) includes hopefully a solution to your problem. Actually, it is not even required/possible to specify ${soem_INCLUDE_DIRS}/soem in your pkg_a anymore.
It would be great if you could check the PR out and leave a comment.

[mgruhler]

#24 contains a similar solution.