Implementation of the {IERC20} interface. This implementation is agnostic to the way tokens are created. This means that a supply mechanism has to be added in a derived contract using {_mint}. For a generic mechanism see {ERC20PresetMinterPauser}. TIP: For a detailed writeup see our guide https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How to implement supply mechanisms]. We have followed general OpenZeppelin guidelines: functions revert instead of returning false on failure. This behavior is nonetheless conventional and does not conflict with the expectations of ERC20 applications. Additionally, an {Approval} event is emitted on calls to {transferFrom}. This allows applications to reconstruct the allowance for all accounts just by listening to said events. Other implementations of the EIP may not emit these events, as it isn't required by the specification. Finally, the non-standard {decreaseAllowance} and {increaseAllowance} functions have been added to mitigate the well-known issues around setting allowances. See {IERC20-approve}.
function allowance(address owner, address spender) external view returns (uint256)
See {IERC20-allowance}.
| Name |
Type |
Description |
| owner |
address |
undefined |
| spender |
address |
undefined |
| Name |
Type |
Description |
| _0 |
uint256 |
undefined |
function approve(address spender, uint256 amount) external nonpayable returns (bool)
See {IERC20-approve}. Requirements: - spender cannot be the zero address.
| Name |
Type |
Description |
| spender |
address |
undefined |
| amount |
uint256 |
undefined |
| Name |
Type |
Description |
| _0 |
bool |
undefined |
function balanceOf(address account) external view returns (uint256)
See {IERC20-balanceOf}.
| Name |
Type |
Description |
| account |
address |
undefined |
| Name |
Type |
Description |
| _0 |
uint256 |
undefined |
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 {_setupDecimals} is called. 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}.
| Name |
Type |
Description |
| _0 |
uint8 |
undefined |
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.
| Name |
Type |
Description |
| spender |
address |
undefined |
| subtractedValue |
uint256 |
undefined |
| Name |
Type |
Description |
| _0 |
bool |
undefined |
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.
| Name |
Type |
Description |
| spender |
address |
undefined |
| addedValue |
uint256 |
undefined |
| Name |
Type |
Description |
| _0 |
bool |
undefined |
function name() external view returns (string)
Returns the name of the token.
| Name |
Type |
Description |
| _0 |
string |
undefined |
function symbol() external view returns (string)
Returns the symbol of the token, usually a shorter version of the name.
| Name |
Type |
Description |
| _0 |
string |
undefined |
function totalSupply() external view returns (uint256)
See {IERC20-totalSupply}.
| Name |
Type |
Description |
| _0 |
uint256 |
undefined |
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.
| Name |
Type |
Description |
| recipient |
address |
undefined |
| amount |
uint256 |
undefined |
| Name |
Type |
Description |
| _0 |
bool |
undefined |
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.
| Name |
Type |
Description |
| sender |
address |
undefined |
| recipient |
address |
undefined |
| amount |
uint256 |
undefined |
| Name |
Type |
Description |
| _0 |
bool |
undefined |
event Approval(address indexed owner, address indexed spender, uint256 value)
| Name |
Type |
Description |
owner indexed |
address |
undefined |
spender indexed |
address |
undefined |
| value |
uint256 |
undefined |
event Transfer(address indexed from, address indexed to, uint256 value)
| Name |
Type |
Description |
from indexed |
address |
undefined |
to indexed |
address |
undefined |
| value |
uint256 |
undefined |