# before_burn · FT4 Rell API · Chromia Docs (concept)

> @extendable function before_ burn(account: account , asset: asset , amount: big_ integer) Extendable function that allows the developer to add more functio

Source: https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.assets/before_burn/

FUNCTION

# before\_burn

```signature
@extendable function before_burn(account: account, asset: asset, amount: big_integer)
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/assets/extensions.rell#lines-87)

Extendable function that allows the developer to add more functionality to the
`burn` function, before the burn happens.

This allows, for example, to check that any given condition is present before burning
is allowed.

If this function throws an exception, the asset will not be burned.

Throws if any extension of this function throws.

**Parameters**

* **account** — the account that is going to lose the burned tokens
* **asset** — the asset that is going to be burned
* **amount** — the amount of tokens that is going to be burned

[View this page on docs.chromia.com](https://docs.chromia.com/pages/ft4-rell/-f-t4%20-library/lib.ft4.core.assets/before_burn.html)Generated API reference, mirrored from the live docs