std-msgs: the recipe does not generate the message header files

[bulwahn]

The CMakeLists file (https://github.com/ros/std_msgs/blob/0.5.7/CMakeLists.txt) contains the line:

generate_messages()

This should produce the message header files in the devel directory.

But, the generated Makefile from the cmake/catkin call does not contain the annotations to call gencpp and generate the header files, that I actually expected.

The generate_messages() or add_message_files(...) in the CMakeLists.txt seems to be ignored.

This needs further investigation.

This issue then leads to the failure in roscpp, e.g. missing String.h file.

[bulwahn]

In https://github.com/ros/ros_comm/blob/groovy-devel/clients/roscpp/CMakeLists.txt,
the line

add_dependencies(roscpp roscpp_gencpp rosgraph_msgs_gencpp std_msgs_gencpp)

should cause the std_msgs cpp headers to be generated.

[bulwahn]

The target std_msgs_gencpp is not available in roscpp (and its also not directly available in std_msgs).
To me it is still unclear where this target is defined.

[herbrechtsmeier]

Can you find the targets in a native ros build? Maybe something with the add_custom_target generation in genmsg don't work.

[herbrechtsmeier]

The problem is the missing /usr/etc/ros/genmsg/* in the sysroot. Without this the "find message generators in all workspaces" in genmsg-extras.cmake.em fails and reports no available message generators.

[bulwahn]

@herbrechtsmeier: So we must just add the files /usr/etc/ros/genmsg/* in the gencpp and genlisp recipe to the sysroot. Is that right?

[herbrechtsmeier]

@bulwahn We have to add the path to the native sysroot and therefore have to manual call sysroot_stage_dir for this path as the path is not a default path and thereby not capture by the default sysroot_stage_dirs function.

You have to add the following lines to the catkin.bbclass:

SYSROOT_PREPROCESS_FUNCS += "catkin_sysroot_preprocess"

catkin_sysroot_preprocess () {
    sysroot_stage_dir ${D}${prefix}/etc ${SYSROOT_DESTDIR}${prefix}/etc
}

[bulwahn]

@herbrechtsmeier: Okay, I see. Your suggestion solves this issue. Please commit that with a reference to this issue.
NB: "#" in the commit message automatically adds a reference in github to the issue you want to refer to.

[herbrechtsmeier]

@bulwahn I will commit a patch when I am back in my office at the end of next week.