~ruther/qmk_firmware

b666921e258838f8eb8dcd9038f6f4f7f4159453 — Evan Travers 7 years ago b4f4576
Reword the `config.h` section

This section didn't include the possibility of a user `config.h`, and it
wasn't clear exactly how the settings override works.
1 files changed, 16 insertions(+), 5 deletions(-)

M docs/getting_started_introduction.md
M docs/getting_started_introduction.md => docs/getting_started_introduction.md +16 -5
@@ 25,23 25,34 @@ In every keymap folder, the following files may be found. Only `keymap.c` is req

# The `config.h` File

There are 2 `config.h` locations:
There are 3 possible `config.h` locations:

* keyboard (`/keyboards/<keyboard>/config.h`)
* userspace (`/users/<user>/config.h`)
* keymap (`/keyboards/<keyboard>/keymaps/<keymap>/config.h`)

If the keymap `config.h` exists, that file is included by the build system and the keyboard `config.h` is not included. If you wish to override settings in your keymap's `config.h` you will need to include some glue code:
The build system automatically picks up the config files in the above order. If you wish to override any setting set by a previous `config.h` you will need to first include some boilerplate code around the settings you wish to change.

```
#ifndef CONFIG_USER_H
#define CONFIG_USER_H

#include "config_common.h"
// overrides go here!

#endif
```

If you want to override a setting from the parent `config.h` file, you need to `#undef` and then `#define` the setting again, like this:
Then to override a setting from the previous `config.h` file you must `#undef` and then `#define` the setting again.

The boilerplate code and setting look like this together:

```c
```
#ifndef CONFIG_USER_H
#define CONFIG_USER_H

// overrides go here!
#undef MY_SETTING
#define MY_SETTING 4

#endif
```