ESP-IDF project with multiple source files - cmake

Question

I started my project with a simple "blink" example and used it as a template to write my code.
This example used only one source file blink.c.
Eventually, I want to a use multi source files project and can't figure out how to configure CMakeLists.txt in order to compile the project.
My CMakeLists.txt is:
cmake_minimum_required(VERSION 3.5)
include($ENV{IDF_PATH}/tools/cmake/project.cmake)
project(blink)
I want to add for example init.c.
I tried different ways, but with no success.
None of idf_component_register() / register_component() worked for me.
Any idea how to correctly configure the project?

Answer 1

Right, the CMake project hierarchy in ESP IDF is a bit tricky. You are looking at the wrong CMakeLists.txt file. Instead of the one in root directory, open the one in blink/main/CMakeLists.txt. This file lists the source files for the "main" component, which is the one you want to use. It would look like this:
idf_component_register(SRCS "blink.c" "init.c"
INCLUDE_DIRS ".")
Make sure your init.c file is in the same directory as this CMakeLists.txt and blink.c.
I also recommend taking a look at the Espressif Build System documentation, it's quite useful.

Answer 2

You should edit the CMakeLists.txt located in your main folder inside your project folder. In addition, you need to put the directory that contains the header files into INCLUDE_DIRS parameter.
For example, if you have this file structure in your project (you're putting init.h inside include folder) as shown below:
blink/
├── main/
│ ├── include/
│ │ └── init.h
│ ├── blink.c
│ ├── CMakeLists.txt
│ ├── init.c
│ └── ...
├── CMakeLists.txt
└── ...
The content in your main/CMakeLists.txt should be:
idf_component_register(SRCS "blink.c" "init.c"
INCLUDE_DIRS "." "include")