Build flags set in my `boards.txt` file not used in the compilation command

[manasIU]

Hi, in my boards.txt file I am using my own build flags (eg. -DFLAGNAME). Arduino-cli recognises these flags but sets these to their default values (0). How do I tell arduino-cli to set certain flags?

[per1234]

Arduino-cli recognises these flags but sets these to their default values (0).

I can't reproduce this. Could you please provide more details, including the exact line from your boards.txt file and a minimal demonstration sketch so that I can reproduce your setup exactly?

How do I tell arduino-cli to set certain flags?

You can use arduino-cli compile's --build-properties option to do things like:

arduino-cli compile --fqbn arduino:avr:uno --build-properties build.extra_flags=-DFLAGNAME SketchName

but be aware this will override the value of the build.extra_flags property that might have been set in your boards.txt.

[bxparks]

I would like to make a feature request for the Arduino-CLI to explicitly support user-defined -D macros without resorting to this hack (which also happens to work in the Arduino IDE CommandLine ). You mentioned in https://forum.arduino.cc/index.php?topic=537500.0 that the Arduino devs have previously been reluctant to do this, but maybe they have changed their minds due to the ongoing work on the Arduino CLI.

[manasIU]

@per1234 My boards.txt file looks something like this :

# Dragonfly-L496RG
Dragonfly-L496RG.menu.debugOptions.none=None
Dragonfly-L496RG.menu.debugOptions.none.build.debugEnable=1

When I compile with verbose on, I see the -DDEBUGENABLE=0 in the output even after using your suggestion of using the --build-properties build.extra_flags=-DFLAGNAME

[per1234]

Is this an existing unmodified hardware core? If so, post a link to it. If you customized it yourself, then you need to provide the full boards.txt and platform.txt.

I also need the complete arduino-cli command you're running.

[per1234]

I would like to make a feature request for the Arduino-CLI to explicitly support user-defined -D macros

We can consider #159 as the dedicated issue for that feature request and use this issue to investigate @manasIU's problem.

[manasIU]

It's a slightly modified Dragonfly-l496RG board with custom debug flag options added (link).
Full arduino-cli command :
arduino-cli compile --fqbn grumpyoldpizza:stm32l4:Dragonfly-L496RG --build-properties build.extra_flags=-DDEBUGENABLE=1 sketch_name --verbose
When I run the above command, I see -DDEBUGENABLE=0 in the verbose output.

[nerdralph]

How do I tell arduino-cli to set certain flags?

You can use arduino-cli compile's --build-properties option to do things like:

arduino-cli compile --fqbn arduino:avr:uno --build-properties build.extra_flags=-DFLAGNAME SketchName

but be aware this will override the value of the build.extra_flags property that might have been set in your boards.txt.

Is there a way to save the fqbn and build-properties in the global config so they don't have to be repeated on the command line? I skimmed the source but couldn't find anything obvious. For now I'm using shell aliases.