All keycodes within quantum are numbers between `0x0000` and `0xFFFF`. Within your `keymap.c` it may look like you have functions and other special cases, but ultimately the C preprocessor will translate those into a single 4 byte integer. QMK has reserved `0x0000` through `0x00FF` for standard keycodes. These are keycodes such as `KC_A`, `KC_1`, and `KC_LCTL`, which are basic keys defined in the USB HID specification.
On this page we have documented keycodes between `0x00FF` and `0xFFFF` which are used to implement advanced quantum features. If you define your own custom keycodes they will be put into this range as well. Keycodes above `0x00FF` may not be used with any of the mod/layer-tap keys listed
# Quantum keycodes
|Name|Description|
|----|-----------|
|`RESET`|Put the keyboard into DFU mode for flashing|
|`DEBUG`|Toggles debug mode|
|`KC_GESC`/`GRAVE_ESC`|Acts as escape when pressed normally but when pressed with Shift or GUI will send a `~`|
|`KC_LSPO`|Left shift when held, open paranthesis when tapped|
|`KC_RSPC`|Right shift when held, close paranthesis when tapped|
|`KC_LEAD`|The [leader key](leader_key.md)|
|`FUNC(n)`/`F(n)`|Call `fn_action(n)`|
|`M(n)`|to call macro n|
|`MACROTAP(n)`|to macro-tap n idk FIXME|
# Bootmagic Keycodes
Shortcuts for bootmagic options (these work even when bootmagic is off.)
|Name|Description|
|----|-----------|
|`MAGIC_SWAP_CONTROL_CAPSLOCK`|Swap Capslock and Left Control|
|`MAGIC_CAPSLOCK_TO_CONTROL`|Treat Capslock like a Control Key|
|`MAGIC_SWAP_LALT_LGUI`|Swap the left Alt and GUI keys|
|`MAGIC_SWAP_RALT_RGUI`|Swap the right Alt and GUI keys|
|`MAGIC_NO_GUI`|Disable the GUI key|
|`MAGIC_SWAP_GRAVE_ESC`|Swap the Grave and Esc key.|
|`MAGIC_SWAP_BACKSLASH_BACKSPACE`|Swap backslack and backspace|
|`MAGIC_HOST_NKRO`|Force NKRO on|
|`MAGIC_SWAP_ALT_GUI`/`AG_SWAP`|Swap Alt and Gui on both sides|
|`MAGIC_UNSWAP_CONTROL_CAPSLOCK`|Disable the Control/Capslock swap|
|`MAGIC_UNCAPSLOCK_TO_CONTROL`|Disable treating Capslock like Control |
|`MAGIC_UNSWAP_LALT_LGUI`|Disable Left Alt and GUI switching|
|`MAGIC_UNSWAP_RALT_RGUI`|Disable Right Alt and GUI switching|
|`MAGIC_UNNO_GUI`|Enable the GUI key |
|`MAGIC_UNSWAP_GRAVE_ESC`|Disable the Grave/Esc swap |
|`MAGIC_UNSWAP_BACKSLASH_BACKSPACE`|Disable the backslash/backspace swap|
|`MAGIC_UNHOST_NKRO`|Force NKRO off|
|`MAGIC_UNSWAP_ALT_GUI`/`AG_NORM`|Disable the Alt/GUI switching|
This is used when multiple keyboard outputs can be selected. Currently this only allows for switching between USB and Bluetooth on keyboards that support both.
Most modifiers work by being held down while you push another key. You can use `OSM()` to setup a "One Shot" modifier. When you tap a one shot mod it will remain is a pressed state until you press another key.
To specify a your modifier you need to pass the `MOD` form of the key. For example, if you want to setup a One Shot Control you would use `OSM(MOD_LCTL)`.
|`CTL_T(kc)`/`LCTL_T(kc)`|`LCTL` when held, `kc` when tapped|
|`RCTL_T(kc)`|`RCTL` when held, `kc` when tapped|
|`SFT_T(kc)`/`LSFT_T(kc)`|`LSFT` when held, `kc` when tapped|
|`RSFT_T(kc)`|`RSFT` when held, `kc` when tapped|
|`ALT_T(kc)`/`LALT_T(kc)`|`LALT` when held, `kc` when tapped|
|`RALT_T(kc)`/`ALGR_T(kc)`|`RALT` when held, `kc` when tapped|
|`GUI_T(kc)`/`LGUI_T(kc)`|`LGUI` when held, `kc` when tapped|
|`RGUI_T(kc)`|`RGUI` when held, `kc` when tapped|
|`C_S_T(kc)`|`LCTL` + `LSFT` when held, `kc` when tapped|
|`MEH_T(kc)`|`LCTL` + `LSFT` + `LALT` when held, `kc` when tapped|
|`LCAG_T(kc)`|`LCTL` + `LALT` + `LGUI` when held, `kc` when tapped|
|`RCAG_T(kc)`|`RCTL` + `RALT` + `RGUI` when held, `kc` when tapped|
|`ALL_T(kc)`|`LCTL` + `LSFT` + `LALT` + `LGUI` when held, `kc` when tapped [more info](http://brettterpstra.com/2012/12/08/a-useful-caps-lock-key/)|
|`SCMD_T(kc)`/`SWIN_T(kc)`|`LGUI` + `LSFT` when held, `kc` when tapped|
|`LCA_T(kc)`|`LCTL` + `LALT` when held, `kc` when tapped|
# US ANSI Shifted symbols
These keycodes correspond to characters that are "shifted" on a standard US ANSI keyboards. They do not have dedicated keycodes but are instead typed by holding down shift and then sending a keycode.
It's important to remember that all of these keycodes send a left shift - this may cause unintended actions if unaccounted for. The short code is preferred in most situations.
These are keycodes that can be used to change the current layer.
|Name|Description|
|----|-----------|
|`LT(layer, kc)`|turn on layer (0-15) when held, kc ([basic keycodes](basic_keycodes.md)) when tapped|
|`TO(layer)`|turn on layer when depressed|
|`MO(layer)`|momentarily turn on layer when depressed (requires `KC_TRNS` on destination layer)|
|`DF(layer)`|sets the base (default) layer|
|`TG(layer)`|toggle layer on/off|
|`TT(layer)`|tap toggle? idk FIXME|
|`OSL(layer)`|switch to layer for one keycode|
# Unicode
These keycodes can be used in conjuction with the [Unicode](unicode_and_additional_language_support.md) support.
|`UNICODE(n)`/`UC(n)`|if `UNICODE_ENABLE`, this will send characters up to `0x7FFF`|
|`X(n)`|if `UNICODEMAP_ENABLE`, also sends unicode via a different method|
# `SAFE_RANGE`, or safely defining custom keycodes
Sometimes you want to define your own custom keycodes to make your keymap easier to read. QMK provides `SAFE_RANGE` to help you do that. `SAFE_RANGE` is the first available keycode in the `0x0000`-`0xFFFF` range and you can use it when creating your own custom keycode enum:
```
enum my_keycodes {
FOO = SAFE_RANGE,
BAR
};
```
You can then use `process_record_user()` to do something with your keycode:
