> ## Documentation Index
> Fetch the complete documentation index at: https://docs.base.org/llms.txt
> Use this file to discover all available pages before exploring further.

# IB20Factory.isB20Initialized

> Returns whether the Factory has fully initialized a B20 token at the given address.

## Signature

```solidity IB20Factory.sol theme={null}
function isB20Initialized(address token) external view returns (bool);
```

| Field               | Value                       |
| ------------------- | --------------------------- |
| Selector            | `0x6a45ba98`                |
| Canonical signature | `isB20Initialized(address)` |

## Description

Returns `true` if and only if `token` bears the `0xB2` address prefix **and** the `0xef` bytecode stub that `createB20` plants when it creates a token. This is the stronger existence check: `isB20(address)` tests the prefix alone and can return `true` for an address the Factory has never touched, whereas `isB20Initialized` confirms the Factory has run to completion at that address.

The flag flips exactly once, the moment the creating `createB20` call returns. It never reverts.

<Note>
  Before `createB20` is called, the predicted token address matches the `0xB2` prefix but carries no stub. Calls to that address are no-ops. Only after `createB20` returns does the `0xef` stub exist, enabling dynamic routing to the token's native logic.
</Note>

## Parameters

| Name    | Type      | Description       |
| ------- | --------- | ----------------- |
| `token` | `address` | Address to check. |

## Returns

| Type   | Description                                                                              |
| ------ | ---------------------------------------------------------------------------------------- |
| `bool` | `true` if `token` is a fully initialized B20 (prefix + stub present); `false` otherwise. |

## Reverts

Never reverts.

## Access Control

View function. No role required.

## Example

```solidity Usage Example theme={null}
IB20Factory(factoryAddress).isB20Initialized(tokenAddress);
```