How to create a static library on nRF Connect SDK/Zephyr

[akif]

Hi,

I am using nrF52840 with nRF Connect, Visual Code Studio (Zephyr) 

Is there any guide or a tutorial with an example that shows how to create a static library on nRF Connect SDK/Zephyr?

There are some topics opened related to this, but none of them have the complete solution.

Please if you can explain in detail, it would help everyone a lot. Thanks

[Håkon Alseth]

Hi,

 

Have you looked at this sample in zephyr?

https://github.com/nrfconnect/sdk-zephyr/blob/main/samples/application_development/external_lib/

This sample both builds and links with a static library.

 

Kind regards,

Håkon

[Torje]

Hello Håkon and Akif,

I feel like that sample does a lot more than what's necessary to simply include a lib. Wouldn't these lines added to the cmake be enough?

zephyr_include_directories(src/lib)
target_sources(app PRIVATE src/lib/libname.c)

I remember having a hard time implementing one my self, and that sample confused me more than it helped.

Please correct me if I'm wrong, but it works for me!

[Håkon Alseth]

To include a lib and to create a lib are two different operations. The below sample shows both.

If you want to include a precompiled static library, you can shorten the whole thing, similar to this:

# SPDX-License-Identifier: Apache-2.0

cmake_minimum_required(VERSION 3.20.0)
find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
project(external_lib)

target_sources(app PRIVATE src/main.c)

include(ExternalProject)

# Add an external project to be able download and build the third
# party library. In this case downloading is not necessary as it has
# been committed to the repository.

set(MYLIB_LIB_DIR     ${CMAKE_CURRENT_SOURCE_DIR}/lib)
set(MYLIB_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/mylib/include)

# Create a wrapper CMake library that our app can link with
add_library(mylib_lib STATIC IMPORTED GLOBAL)
add_dependencies(
  mylib_lib
  mylib_project
  )
set_target_properties(mylib_lib PROPERTIES IMPORTED_LOCATION             ${MYLIB_LIB_DIR}/libmylib.a)
set_target_properties(mylib_lib PROPERTIES INTERFACE_INCLUDE_DIRECTORIES ${MYLIB_INCLUDE_DIR})

target_link_libraries(app PUBLIC mylib_lib)

 

Kind regards,

Håkon