> For the complete documentation index, see [llms.txt](https://docs.fringe.fi/smart-contract-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fringe.fi/smart-contract-documentation/openzeppelin/contracts-upgradeable/token/erc-20/extensions/erc20wrapperupgradeable.md).

# ERC 20 Wrapper Upgradeable

*Extension of the ERC20 token contract to support token wrapping. Users can deposit and withdraw "underlying tokens" and receive a matching number of "wrapped tokens". This is useful in conjunction with other modules. For example, combining this wrapping mechanism with {ERC20Votes} will allow the wrapping of an existing "basic" ERC20 into a governance token. Available since v4.2.*

## Methods

### allowance

```solidity
function allowance(address owner, address spender) external view returns (uint256)
```

*See {IERC20-allowance}.*

#### Parameters

| Name    | Type    | Description |
| ------- | ------- | ----------- |
| owner   | address | undefined   |
| spender | address | undefined   |

#### Returns

| Name | Type    | Description |
| ---- | ------- | ----------- |
| \_0  | uint256 | undefined   |

### approve

```solidity
function approve(address spender, uint256 amount) external nonpayable returns (bool)
```

*See {IERC20-approve}. Requirements: - `spender` cannot be the zero address.*

#### Parameters

| Name    | Type    | Description |
| ------- | ------- | ----------- |
| spender | address | undefined   |
| amount  | uint256 | undefined   |

#### Returns

| Name | Type | Description |
| ---- | ---- | ----------- |
| \_0  | bool | undefined   |

### balanceOf

```solidity
function balanceOf(address account) external view returns (uint256)
```

*See {IERC20-balanceOf}.*

#### Parameters

| Name    | Type    | Description |
| ------- | ------- | ----------- |
| account | address | undefined   |

#### Returns

| Name | Type    | Description |
| ---- | ------- | ----------- |
| \_0  | uint256 | undefined   |

### decimals

```solidity
function decimals() external view returns (uint8)
```

*Returns the number of decimals used to get its user representation. For example, if `decimals` equals `2`, a balance of `505` tokens should be displayed to a user as `5.05` (`505 / 10 ** 2`). Tokens usually opt for a value of 18, imitating the relationship between Ether and Wei. This is the value {ERC20} uses, unless this function is overridden; NOTE: This information is only used for display purposes: it in no way affects any of the arithmetic of the contract, including {IERC20-balanceOf} and {IERC20-transfer}.*

#### Returns

| Name | Type  | Description |
| ---- | ----- | ----------- |
| \_0  | uint8 | undefined   |

### decreaseAllowance

```solidity
function decreaseAllowance(address spender, uint256 subtractedValue) external nonpayable returns (bool)
```

*Atomically decreases the allowance granted to `spender` by the caller. This is an alternative to {approve} that can be used as a mitigation for problems described in {IERC20-approve}. Emits an {Approval} event indicating the updated allowance. Requirements: - `spender` cannot be the zero address. - `spender` must have allowance for the caller of at least `subtractedValue`.*

#### Parameters

| Name            | Type    | Description |
| --------------- | ------- | ----------- |
| spender         | address | undefined   |
| subtractedValue | uint256 | undefined   |

#### Returns

| Name | Type | Description |
| ---- | ---- | ----------- |
| \_0  | bool | undefined   |

### depositFor

```solidity
function depositFor(address account, uint256 amount) external nonpayable returns (bool)
```

*Allow a user to deposit underlying tokens and mint the corresponding number of wrapped tokens.*

#### Parameters

| Name    | Type    | Description |
| ------- | ------- | ----------- |
| account | address | undefined   |
| amount  | uint256 | undefined   |

#### Returns

| Name | Type | Description |
| ---- | ---- | ----------- |
| \_0  | bool | undefined   |

### increaseAllowance

```solidity
function increaseAllowance(address spender, uint256 addedValue) external nonpayable returns (bool)
```

*Atomically increases the allowance granted to `spender` by the caller. This is an alternative to {approve} that can be used as a mitigation for problems described in {IERC20-approve}. Emits an {Approval} event indicating the updated allowance. Requirements: - `spender` cannot be the zero address.*

#### Parameters

| Name       | Type    | Description |
| ---------- | ------- | ----------- |
| spender    | address | undefined   |
| addedValue | uint256 | undefined   |

#### Returns

| Name | Type | Description |
| ---- | ---- | ----------- |
| \_0  | bool | undefined   |

### name

```solidity
function name() external view returns (string)
```

*Returns the name of the token.*

#### Returns

| Name | Type   | Description |
| ---- | ------ | ----------- |
| \_0  | string | undefined   |

### symbol

```solidity
function symbol() external view returns (string)
```

*Returns the symbol of the token, usually a shorter version of the name.*

#### Returns

| Name | Type   | Description |
| ---- | ------ | ----------- |
| \_0  | string | undefined   |

### totalSupply

```solidity
function totalSupply() external view returns (uint256)
```

*See {IERC20-totalSupply}.*

#### Returns

| Name | Type    | Description |
| ---- | ------- | ----------- |
| \_0  | uint256 | undefined   |

### transfer

```solidity
function transfer(address recipient, uint256 amount) external nonpayable returns (bool)
```

*See {IERC20-transfer}. Requirements: - `recipient` cannot be the zero address. - the caller must have a balance of at least `amount`.*

#### Parameters

| Name      | Type    | Description |
| --------- | ------- | ----------- |
| recipient | address | undefined   |
| amount    | uint256 | undefined   |

#### Returns

| Name | Type | Description |
| ---- | ---- | ----------- |
| \_0  | bool | undefined   |

### transferFrom

```solidity
function transferFrom(address sender, address recipient, uint256 amount) external nonpayable returns (bool)
```

*See {IERC20-transferFrom}. Emits an {Approval} event indicating the updated allowance. This is not required by the EIP. See the note at the beginning of {ERC20}. Requirements: - `sender` and `recipient` cannot be the zero address. - `sender` must have a balance of at least `amount`. - the caller must have allowance for `sender`'s tokens of at least `amount`.*

#### Parameters

| Name      | Type    | Description |
| --------- | ------- | ----------- |
| sender    | address | undefined   |
| recipient | address | undefined   |
| amount    | uint256 | undefined   |

#### Returns

| Name | Type | Description |
| ---- | ---- | ----------- |
| \_0  | bool | undefined   |

### underlying

```solidity
function underlying() external view returns (contract IERC20Upgradeable)
```

#### Returns

| Name | Type                       | Description |
| ---- | -------------------------- | ----------- |
| \_0  | contract IERC20Upgradeable | undefined   |

### withdrawTo

```solidity
function withdrawTo(address account, uint256 amount) external nonpayable returns (bool)
```

*Allow a user to burn a number of wrapped tokens and withdraw the corresponding number of underlying tokens.*

#### Parameters

| Name    | Type    | Description |
| ------- | ------- | ----------- |
| account | address | undefined   |
| amount  | uint256 | undefined   |

#### Returns

| Name | Type | Description |
| ---- | ---- | ----------- |
| \_0  | bool | undefined   |

## Events

### Approval

```solidity
event Approval(address indexed owner, address indexed spender, uint256 value)
```

#### Parameters

| Name              | Type    | Description |
| ----------------- | ------- | ----------- |
| owner `indexed`   | address | undefined   |
| spender `indexed` | address | undefined   |
| value             | uint256 | undefined   |

### Transfer

```solidity
event Transfer(address indexed from, address indexed to, uint256 value)
```

#### Parameters

| Name           | Type    | Description |
| -------------- | ------- | ----------- |
| from `indexed` | address | undefined   |
| to `indexed`   | address | undefined   |
| value          | uint256 | undefined   |