Compiling with Make

Now that we've installed Apache NuttX prerequisites and downloaded the source code, we are ready to compile the source code into an executable binary file that can be run on the embedded board.

Initialize Configuration

The first step is to initialize NuttX configuration for a given board, based on a pre-existing configuration. To list all supported configurations you can do:

 cd nuttx
 ./tools/configure.sh -L | less

The output is in the format <board name>:<board configuration>. You will see that generally all boards support the nsh configuration which is a good starting point since it enables booting into the interactive command line [[/application](]{.title-ref}/application.md)s/nsh/index`.

To choose a configuration you pass the <board name>:<board configuration> option to configure.sh and indicate your host platform, such as:

 cd nuttx
 ./tools/configure.sh -l stm32f4discovery:nsh

The -l tells use that we're on Linux (macOS and Windows builds are possible). Use the -h argument to see all available options.

You can then customize this configuration by using the menu based configuration system with:

 cd nuttx
 make menuconfig

Modifying the configuration is covered in [[configuring]{.title-ref}.]([configuring]{.title-ref}..md)

Build NuttX

We can now build NuttX. To do so, you can simply run:

 cd nuttx
 make

The build will complete by generating the binary outputs inside nuttx directory. Typically this includes the nuttx ELF file (suitable for debugging using gdb) and a nuttx.bin file that can be flashed to the board.

To clean the build, you can do:

 make clean

Tip

To increase build speed (or of any other target such as clean), you can pass the -jN flag to make, where N is the number of parallel jobs to start (usually, the number of processors on your machine).