Macros allow you to send multiple keystrokes when pressing just one key. QMK has a number of ways to define and use macros. These can do anything you want: type common phrases for you, copypasta, repetitive game movements, or even help you code.
!> **Security Note**: While it is possible to use macros to send passwords, credit card numbers, and other sensitive information it is a supremely bad idea to do so. Anyone who gets a hold of your keyboard will be able to access that information by opening a text editor.
Sometimes you just want a key to type out words or phrases. For the most common situations we've provided `SEND_STRING()`, which will type out your string (i.e. a sequence of characters) for you. All ASCII characters that are easily translated to a keycode are supported (e.g. `\n\t`).
We first define a new custom keycode in the range not occupied by any other keycodes.
Then we use the `process_record_user` function, which is called whenever a key is pressed or released, to check if our custom keycode has been activated.
If yes, we send the string `"QMK is the best thing ever!"` to the computer via the `SEND_STRING` macro (this is a C preprocessor macro, not to be confused with QMK macros).
We return `true` to indicate to the caller that the key press we just processed should continue to be processed as normal (as we didn't replace or alter the functionality).
By default, it assumes a US keymap with a QWERTY layout; if you want to change that (e.g. if your OS uses software Colemak), include this somewhere in your keymap:
If for some reason you're manipulating strings and need to print out something you just generated (instead of being a literal, constant string), you can use `send_string()`, like this:
There are some functions you may find useful in macro-writing. Keep in mind that while you can write some fairly advanced code within a macro, if your functionality gets too complex you may want to define a custom keycode instead. Macros are meant to be simple.
### `record->event.pressed`
This is a boolean value that can be tested to see if the switch is being pressed or released. An example of this is
```c
if (record->event.pressed) {
// on keydown
} else {
// on keyup
}
```
### `register_code(<kc>);`
This sends the `<kc>` keydown event to the computer. Some examples would be `KC_ESC`, `KC_C`, `KC_4`, and even modifiers such as `KC_LSFT` and `KC_LGUI`.
### `unregister_code(<kc>);`
Parallel to `register_code` function, this sends the `<kc>` keyup event to the computer. If you don't use this, the key will be held down until it's sent.
### `tap_code(<kc>);`
This will send `register_code(<kc>)` and then `unregister_code(<kc>)`. This is useful if you want to send both the press and release events ("tap" the key, rather than hold it).
If you're having issues with taps (un)registering, you can add a delay between the register and unregister events by setting `#define TAP_CODE_DELAY 100` in your `config.h` file. The value is in milliseconds.
### `register_code16(<kc>);`, `unregister_code16(<kc>);` and `tap_code16(<kc>);`
These functions work similar to their regular counterparts, but allow you to use modded keycodes (with Shift, Alt, Control, and/or GUI applied to them).
Eg, you could use `register_code16(S(KC_5));` instead of registering the mod, then registering the keycode.
### `clear_keyboard();`
This will clear all mods and keys currently pressed.
### `clear_mods();`
This will clear all mods currently pressed.
### `clear_keyboard_but_mods();`
This will clear all keys besides the mods currently pressed.
This macro will register `KC_LALT` and tap `KC_TAB`, then wait for 1000ms. If the key is tapped again, it will send another `KC_TAB`; if there is no tap, `KC_LALT` will be unregistered, thus allowing you to cycle through windows.
```c
bool is_alt_tab_active = false; # ADD this near the begining of keymap.c
uint16_t alt_tab_timer = 0; # we will be using them soon.
enum custom_keycodes { # Make sure have the awesome keycode ready
This defines two macros which will be run when the key they are assigned to is pressed. If instead you'd like them to run when the key is released you can change the if statement:
If you have a bunch of macros you want to refer to from your keymap while keeping the keymap easily readable you can name them using `#define` at the top of your file.