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

> function block_ height(integer: integer): rule_parameters First step in creating a rule_expression based on block_height . Should be passed
to an operator 

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

FUNCTION

# block\_height

```signature
function block_height(integer: integer): rule_parameters
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/accounts/auth_descriptor_rule_expression.rell#lines-157)

First step in creating a `rule_expression` based on `block_height`. Should be passed
to an operator function, e.g. `less_than(block_height(100))`

**Parameters**

* **integer** — the value to use in the rule

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