qmk-firmware/FAQ-Keymap.md

# Keymap
## Power key doesn't work
Use `KC_PWR` instead of `KC_POWER` or vice versa.
- `KC_PWR` works with Windows and Linux, not with OSX.
- `KC_POWER` works with OSX and Linux, not with Windows.

http://geekhack.org/index.php?topic=14290.msg1327264#msg1327264

## Oneshot modifier
Solves my personal 'the' problem. I often got 'the' or 'THe' wrongly instead of 'The'.  Oneshot Shift mitgates this for me.
https://github.com/tmk/tmk_keyboard/issues/67

## Modifier/Layer stuck
Modifier keys or layers can be stuck unless layer switching is configured properly.
For Modifier keys and layer actions you have to place `KC_TRANS` on same position of destination layer to  unregister the modifier key or return to previous layer on release event.

https://github.com/tmk/tmk_keyboard/blob/master/doc/keymap.md#31-momentary-switching
http://geekhack.org/index.php?topic=57008.msg1492604#msg1492604


## Mechanical Lock Switch Support
https://github.com/tmk/tmk_keyboard#mechanical-locking-support

This feature is for *mechanical lock switch* like this Alps one.
http://deskthority.net/wiki/Alps_SKCL_Lock

Using enabling this feature and using keycodes `LCAP`, `LNUM` or `LSCR` in keymap you can use physical locking CapsLock, NumLock or ScrollLock keys as you expected.

Old vintage mechanical keyboards occasionally have lock switches but modern ones don't have. ***You don't need this feature in most case and just use keycodes `CAPS`, `NLCK` and `SLCK`.***


## Input language specific charactors other than ASCII like Cédille 'Ç'
NO UNIVERSAL METHOD TO INPUT THOSE WORKS OVER ALL SYSTEMS. You have to define MACRO in way specific to your OS or layout.

See this post for example code.
http://deskthority.net/workshop-f7/tmk-keyboard-firmware-collection-t4478-120.html#p195620

On **Windows** you can use `AltGr` key or **Alt code**.
- http://en.wikipedia.org/wiki/AltGr_key
- http://en.wikipedia.org/wiki/Alt_code

On **Mac** OS defines `Option` key combinations.
- http://en.wikipedia.org/wiki/Option_key#Alternative_keyboard_input

On **Xorg** you can use `compose` key, instead.
- http://en.wikipedia.org/wiki/Compose_key

And see this for **Unicode** input.
- http://en.wikipedia.org/wiki/Unicode_input