# Return values: the answer a function gives back

[Concepts explained](README.md)

A **return value** is the answer a function sends back to the code that called it. Your program can save that answer, calculate with it, compare it, or display it.

```pliro
# language: en
function double(value):
    return value * 2
let answer = double(6)
say answer + 1
```

`double(6)` returns twelve. The program stores twelve in `answer`, then prints thirteen.

## Returning is different from displaying

`say` puts text in the output. `return` gives a value to the caller. A function can display a message without returning that message. If you want to use the result in another calculation, returning it is useful.

In Pliro, `return` also ends the current function call. Instructions after it on that path are skipped. It does not stop every other part of the application; [exitApp](../builtins/exitApp.md) has that different job.

A function that reaches its end without returning a value produces `none`. A bare `return` also gives `none`. This is Pliro's “no value,” not zero and not empty text.

## Read a reference page

A built-in's **Returns** or **Return value** section tells you what kind of answer to expect. `length` returns a Number. A drawing command may return None while still producing a visible effect.

Try saving `double(3)` and using it twice. How many times must the function run?

[Functions](../syntax/function.md) · [Side effects](side-effects.md)