# Userspace: Sharing Code Between Keymaps

If you use more than one keyboard with a similar keymap, you might see the benefit in being able to share code between them. Create your own folder in `users/` named the same as your keymap (ideally your GitHub username, `<name>`) with the following structure:

* `/users/<name>/` (added to the path automatically)
  * `readme.md` (optional, recommended)
  * `rules.mk` (included automatically)
  * `config.h` (included automatically)
  * `<name>.h` (optional)
  * `<name>.c` (optional)
  * `cool_rgb_stuff.c` (optional)
  * `cool_rgb_stuff.h` (optional)


All this only happens when you build a keymap named `<name>`, like this:

    make planck:<name>

For example,

    make planck:jack

Will include the `/users/jack/` folder in the path, along with `/users/jack/rules.mk`.  

!> This `name` can be [overridden](#override-default-userspace), if needed.  

## `Rules.mk`

The `rules.mk` is one of the two files that gets processed automatically.  This is how you add additional source files (such as  `<name>.c`) will be added when compiling.

It's highly recommended that you use `<name>.c` as the default source file to be added. And to add it, you need to add it the SRC in `rules.mk` like this:

    SRC += <name>.c

Additional files may be added in the same way - it's recommended you have one named `<name>`.c/.h to start off with, though. 

The `/users/<name>/rules.mk` file will be included in the build _after_ the `rules.mk` from your keymap. This allows you to have features in your userspace `rules.mk` that depend on individual QMK features that may or may not be available on a specific keyboard. 

For example, if you have RGB control features shared between all your keyboards that support RGB lighting, you can add support for that if the RGBLIGHT feature is enabled:
```make
ifeq ($(strip $(RGBLIGHT_ENABLE)), yes)
  # Include my fancy rgb functions source here
  SRC += cool_rgb_stuff.c
endif
```

Alternatively, you can `define RGB_ENABLE` in your keymap's `rules.mk` and then check for the variable in your userspace's `rules.mk` like this: