Creating and distributing a static library for Zephyr

[newUser]

Hi,

We would like to share a part of our Zephyr software with a customer. We would like to share a static library, not the source code. The code to be included in the static library is a few .c files and a few .h files.

The code starts some threads and has some internal logic, and of course a public interface for configuration, initialization, starting and stopping processes, etc. It also uses Zephyr kernel calls internally, like k_msgq_put(). This last call leads to problems:

Rebuilding ‘zephyr/zephyr_prebuilt.elf’ from solution ‘build’ in configuration ‘Common’
  Compiling ‘empty_file.c’
  Linking ‘zephyr_prebuilt.elf’
    B         1 MB      1.92%
    B       448 KB      1.25%
    B         2 KB      4.30%
    lib/liblib.a(lib.c.obj): in function `k_msgq_put':
    undefined reference to `z_impl_k_msgq_put'
    ld returned 1 exit status
Build failed

Please checkout this minimal reproducible example:
4456.with_source.zip

How do we solve this? We would like to be able to distribute the library after building it for the correct hardware board and project settings, so that someone else can just include it and use the functions defined in the header files in the include folder.

[newUser]

Replacing k_msgq_put() with LOG_INF() in the minimal example is working just fine. It must be something with the linking of the extern.

[Kenneth]

This is not something I have looked into, but I could find some threads on zephyr project that may be relevant:
http://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/application/index.html?highlight=external_lib#support-for-building-third-party-library-code 

Hopefully someone here on Devzone may have also tried this. You may also check out the zephyr community:
https://github.com/zephyrproject-rtos/zephyr#resources