How to build MicroPython with multiple external user C modules

[saraverbeecke]

Hello,

I want to build MicroPython with 2 external user C modules namely: st7789 and ulab.
I can build MicroPython with one of them, but I don't know how to add multiple C user modules in the make command...
Example for an ESP32:

make BOARD=GENERIC_S3_SPIRAM_OCT USER_C_MODULES="$REPO_ROOT/ulab/code/micropython.cmake"

Thanks,
Sara

[Wind-stormger]

I care about this too.

[cwalther]

This seems well documented at https://docs.micropython.org/en/latest/develop/cmodules.html#compiling-the-cmodule-into-micropython, is there anything wrong with it? I haven’t done this myself on CMake-based ports so I cannot comment.

[ricksorensen]

I am doing this currently. I have a common .cmake file that invokes the cmake files for the modules I wish to build ... for example:

In mymods directory I have the command cmake file and the (git cloned) st7789 and ulab source:

$ls -1 mymods -F
micropython.cmake
st7789_mpy/
ulab/

and the cmake file is:

$ cat mymods/micropython.cmake 
include(${CMAKE_CURRENT_LIST_DIR}/ulab/code/micropython.cmake)
include(${CMAKE_CURRENT_LIST_DIR}/st7789_mpy/st7789/micropython.cmake)

I can then build with

make USER_C_MODULES="${full_path}/mymods/micropython.cmake"

[saraverbeecke]

Thanks that is what I needed.

[trentp-igor]

Could USER_C_MODULES be a list? Seems like that way it wouldn't be necessary to add additional files to build more than one extension.

[andrewleech]

The standard usage is to have USER_C_MODULES pointing at a folder which contains one or more c extensions to include.

The example in https://docs.micropython.org/en/latest/develop/cmodules.html#compiling-the-cmodule-into-micropython is set to https://github.com/micropython/micropython/tree/master/examples/usercmodule which contains three separate extensions.

On make based ports this is all you need to do, make finds and includes all modules in that folder.

It's only for the more annoying cmake based ports (like esp) that you need to manually list the modules you want, as per https://github.com/micropython/micropython/blob/master/examples/usercmodule/micropython.cmake

[xyzzy42]

It seems like most external modules have their code nested some level under the root. For example, ulab/code. So if someone wants to pull in multiple extensions as git submodules, they're going to have paths in the project root like:

modules/ulab/code
modules/st7789_mpy/st7789

To put them all a single directory would require another directory of relative symlinks.

If USER_C_MODULES was a list, then it would be possible to inject multiple external modules with only a change to build parameters and it would work if the modules can't all be in a single directory because the upstream projects that provide them are not organized this way.