A command line tool for compiling Arduino sketches
Go C++ C Arduino Other
Latest commit bc2c38f Dec 15, 2016 @facchinm facchinm committed on GitHub Release 1.3.23


Arduino Builder Build Status

A command line tool for compiling Arduino sketches

This tool is able to parse Arduino Hardware specifications, properly run gcc and produce compiled sketches.

An Arduino sketch differs from a standard C program in that it misses a main (provided by the Arduino core), function prototypes are not mandatory, and libraries inclusion is automagic (you just have to #include them). This tool generates function prototypes and gathers library paths, providing gcc with all the needed -I params.


  • -compile or -dump-prefs or -preprocess: Optional. If omitted, defaults to -compile. -dump-prefs will just print all build preferences used, -compile will use those preferences to run the actual compiler, -preprocess will only print preprocessed code to stdout.

  • -hardware: Mandatory. Folder containing Arduino platforms. An example is the hardware folder shipped with the Arduino IDE, or the packages folder created by Arduino Boards Manager. Can be specified multiple times. If conflicting hardware definitions are specified, the last one wins.

  • -tools: Mandatory. Folder containing Arduino tools (gcc, avrdude...). An example is the hardware/tools folder shipped with the Arduino IDE, or the packages folder created by Arduino Boards Manager. Can be specified multiple times.

  • -libraries: Optional. Folder containing Arduino libraries. An example is the libraries folder shipped with the Arduino IDE. Can be specified multiple times.

  • -fqbn: Mandatory. Fully Qualified Board Name, e.g.: arduino:avr:uno

  • -build-path: Optional. Folder where to save compiled files. If omitted, a folder will be created in the temporary folder specified by your OS.

  • -prefs=key=value: Optional. It allows to override some build properties.

  • -warnings: Optional, can be "none", "default", "more" and "all". Defaults to "none". Used to tell gcc which warning level to use (-W flag).

  • -verbose: Optional, turns on verbose mode.

  • -quiet: Optional, supresses almost every output.

  • -debug-level: Optional, defaults to "5". Used for debugging. Set it to 10 when submitting an issue.

  • -core-api-version: Optional, defaults to "10600". The version of the Arduino IDE which is using this tool.

  • -logger: Optional, can be "human" or "machine". Defaults to "human". If "machine", messages emitted will be in a format which the Arduino IDE understands and that it uses for I18N.

  • -version: if specified, prints version and exits.

  • -build-options-file: it specifies path to a local build.options.json file (see paragraph below), which allows you to omit specifying params such as -hardware, -tools, -libraries, -fqbn, -pref and -ide-version.

  • -vid-pid: when specified, VID/PID specific build properties are used, if boards supports them.

Final mandatory parameter is the sketch to compile (of course).

What is and how to use build.options.json file

Every time you run this tool, it will create a build.options.json file in build path. It's used to understand if build options (such as hardware folders, fqbn and so on) were changed when compiling the same sketch. If they changed, the whole build path is wiped out. If they didn't change, previous compiled files will be reused if the corresponding source files didn't change as well. You can save this file locally and use it instead of specifying -hardware, -tools, -libraries, -fqbn, -pref and -ide-version.

Using it for continuously verify your libraries or cores

See Doing continuous integration with arduino builder.

Building from source

You need Go 1.6.3.

Repo root contains the script setup_go_env_vars. Use it as is or as a template for setting up Go environment variables.

To install codereview/patch you have to install Mercurial first.

Once done, run the following commands:

go get github.com/go-errors/errors
go get github.com/stretchr/testify
go get github.com/jstemmer/go-junit-report
go build arduino.cc/arduino-builder


In order to run the tests, type:

go test arduino.cc/...

This runs all tests, showing any failures and a summary at the end. Add the -v option to show each test as it is being ran. Currently, arduino-builder itself also generates copious output, even for non-failing testcases and without -v, and testing does not stop at the first failure, so you probably want to redirect test output so you can scroll back to find any failures.

To run a single test, use the -run option, which accepts a regular expression (see also go help testflag).

go test arduino.cc/... -run 'TestBuilderEmptySketch'
go test arduino.cc/... -run 'TestPrototypesAdder.*'

In jenkins, use

go test -v arduino.cc/... | bin/go-junit-report > report.xml

The first time you run the tests, some needed files (toolchains and source files) will be downloaded, which needs about 1GB of space (at the time of writing). If you have a slow connection, this download might exceed the default 10 minute timeout for a single test. If you run into this, add -timeout 60m or similar to the commandline to extend the timeout. If you are running on slower system (like a rasbperry pi), increasing the timeout might be needed as well.

License and Copyright

arduino-builder is licensed under General Public License version 2, as published by the Free Software Foundation. See LICENSE.txt.

Copyright (C) 2015 Arduino LLC and contributors

See https://www.arduino.cc/ and https://github.com/arduino/arduino-builder/graphs/contributors