How to build only SDK?

[hustenhabas]

Hello dear coders. I would like to know how can I use GNU make to build only the esp-idf SDK and then build my app in a separate way. Currently even using "make app" the makefiles compile the whole esp-idf. I need to make my project build independent from the SDK.

How can I compile only the SDK files?
How can I link the SDK compiled files to my custom app make?

Thanks!

[ESP_Sprite]

Are you asking this for compilation speed reasons, or do you have another reason you want to have a precompiled idf? If for speed reasons:

Currently even using "make app" the makefiles compile the whole esp-idf.

That should not happen; CMake should only build the changed source files and their dependencies. One exception is if you change an option in menuconfig; that touches most of the sources you get a near-full rebuild. I'd like to hear more about your setup if that's the issue.

[hustenhabas]

Are you asking this for compilation speed reasons, or do you have another reason you want to have a precompiled idf? If for speed reasons:

It's for project organization and build pattern of my company. I need create a make command for the SDK to build the .o files and a diferent make command to compile my project and link with the precompiled library. Currently the esp-idf/make/project.mk compile both of them and automatically creates the .elf and .bin.

[ESP_Sprite]

Sorry, there's no 'nice' way to do this. Arduino uses this, but their way to compile the libraries is to simply compile a 'hello world' app and copy out the resulting .a files. ESP-IDF however doesn't really have a way in which you can feed it the SDK .a files and it runs a compile from that, so you'd have to hack the build system to accept that.

Also note that using 'make' for building esp-idf applications is deprecated; for ESP-IDF 4 it already doesn't work for new chips (S3, C3, ...) and for ESP-IDF 5 we'll remove it entirely.

[hustenhabas]

Sorry, there's no 'nice' way to do this. Arduino uses this, but their way to compile the libraries is to simply compile a 'hello world' app and copy out the resulting .a files. ESP-IDF however doesn't really have a way in which you can feed it the SDK .a files and it runs a compile from that, so you'd have to hack the build system to accept that.

Thanks for the answer!!
now its clear that we should use Cmake and idf.py build