"stefan.hristozov via Lists.Zephyrproject.Org"
<stefan.hristozov=aisec.fraunhofer.de@lists.zephyrproject.org> writes:

Hi,

I want to add a module to my project. My folder structure looks like this:

<top dir>
|---modules
|      |---module1
|      |      |---CMakeLists.txt
|      |      |---inc
|      |      |---src
|      |      |---zephyr
|      |            |---module.yml
|      |---module2
|---app
|---app1

*Where modules/module1/CMakeLists.txt:*

zephyr_interface_library_named(test)
target_include_directories(test INTERFACE inc)
zephyr_library()
zephyr_library_sources(
src/test.c
)
zephyr_library_link_libraries(test)
target_link_libraries(test INTERFACE zephyr_interface)

*modules/module1/zephyr/module.yml:*

build:
cmake: .

*app/app1/CMakeLists.txt:*
cmake_minimum_required (VERSION 3.13.1)
include ( $ENV{ZEPHYR_BASE} /cmake/app/boilerplate.cmake NO_POLICY_SCOPE)
project (NONE)

set ( $ENV{ZEPHYR_EXTRA_MODULES} pbs_path/module1)

Looking at this quickly, ZEPHYR_EXTRA_MODULES needs to be set before
including the boilerplate file, not before. You can also set it as an
ordinary CMake variable; you don't need to set it in the environment.

FILE (GLOB app_sources src/*.c)
target_sources (app PRIVATE ${app_sources} )
target_include_directories (app PRIVATE $ENV{ZEPHYR_BASE} /subsys/net/ip)

target_link_libraries (app PRIVATE test)

Unfortunately,  with this set up module1 doesn't get compiled and I get a linker error when I try to use functions from that module. I assume that something goes wrong with ZEPHYR_EXTRA_MODULES but I don't know what.

HTH,
Marti

Best regards
Stefan