cmake-kconfig

Minimal cmake project with Kconfig integration adapted from Zephyr.

All Zephyr-related stuff was removed and adopted to be used in standalone projects.

Example

Default build using a provided configurations called test.

cmake -B build -DBUILD_CONFIG=test -GNinja
cmake --build build
./build/test1

Note the above uses the config provided by:

configs/test_defconfig

Updating the configuration:

ninja -C build menuconfig

This will bring up an interactive menu to turn options on/off and it will save a .config file in the build directory.

The test_defconfig can be updated by copying the build/.config file to configs/test_defconfig and committing.

Before any targets are built an autoconf.h header file is generated in ${AUTOCONF_DIR}:

build/kconfig/include/generate/autoconf.h

This allows everything to have a common configuration.

Auto-generated autoconf.h resides in ${AUTOCONF_DIR}, add it to your target's include search path:

target_include_directories(your_target PUBLIC ${AUTOCONF_DIR})

Cmake

if(CONFIG_TEST_OPTION)
    message("Config test_option is enabled")
endif()

Make

-include build/.config

ifeq ($(CONFIG_TEST_OPTION),y)
objs += src/test_option.o
endif

C/C++ ...

#include <autoconf.h>

#ifdef CONFIG_TEST_OPTION
// Code built for option.
#endif

Kconfig

Kconfig is Brilliant! It manages a unified configuration separately from the main source code that can be used with the build system and source code.

It is the best-in-class configuration management tool that exists for embedded C code, period.

It allows dependencies to be defined between different config options. And the best thing is, some really smart people have worked all this out before, so we get a really powerful system for little effort/cost.