---
title: The Build System
description: Learn how the build system in RIOT works
---

RIOT uses [GNU make](https://www.gnu.org/software/make/) as build system. The
simplest way to compile and link an application with RIOT, is to set up a
Makefile providing at least the following variables:

 * `APPLICATION`: should contain the (unique) name of your application
 * `BOARD`: specifies the platform the application should be built for by
   default
 * `RIOTBASE`: specifies the path to your copy of the RIOT repository (note,
   that you may want to use `$(CURDIR)` here, to give a relative path)

Additionally it has to include the `Makefile.include`, located in RIOT's root
directory:

```make title="a minimal application Makefile"
APPLICATION = mini-makefile
BOARD ?= native
RIOTBASE ?= $(CURDIR)/../RIOT

include $(RIOTBASE)/Makefile.include
```

You can use Make's `?=` operator in order to allow overwriting
variables from the command line. For example, you can easily specify the target
platform, using the sample Makefile, by invoking make like this:

```shell
make BOARD=iotlab-m3
```

Besides typical targets like `clean`, `all`, or `doc`, RIOT provides the
special targets `flash` and `term` to invoke the configured flashing and
terminal tools for the specified platform. These targets use the variable
`PORT` for the serial communication to the device. Neither this variable nor
the targets `flash` and `term` are mandatory for the native port.

For the native port, `PORT` has a special meaning: it is used to identify the
tap interface if the `netdev_tap` module is used. The target `debug` can be
used to invoke a debugger on some platforms. For the native port the additional
targets such as `all-valgrind` and `valgrind` exist. Refer to
`cpu/native/README.md` for additional information

Some RIOT directories contain special Makefiles like `Makefile.base`,
`Makefile.include` or `Makefile.dep`. The first one can be included into other
Makefiles to define some standard targets. The files called `Makefile.include`
are used in `boards` and `cpu` to append target specific information to
variables like `INCLUDES`, setting the include paths. `Makefile.dep` serves to
define dependencies.

Unless specified otherwise, make will create an elf-file as well as an Intel
hex file in the `bin` folder of your application directory.

Learn more about the build system in the
[Wiki](https://github.com/RIOT-OS/RIOT/wiki/The-Make-Build-System)