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ERC20Votes

Extension of ERC20 to support Compound-like voting and delegation. This version is more generic than Compound's, and supports token supply up to 2^224^ - 1, while COMP is limited to 2^96^ - 1. NOTE: If exact COMP compatibility is required, use the {ERC20VotesComp} variant of this module. This extension keeps a history (checkpoints) of each account's vote power. Vote power can be delegated either by calling the {delegate} function directly, or by providing a signature to be used with {delegateBySig}. Voting power can be queried through the public accessors {getVotes} and {getPastVotes}. By default, token balance does not account for voting power. This makes transfers cheaper. The downside is that it requires users to delegate to themselves in order to activate checkpoints and have their voting power tracked. Available since v4.2.

Methods​

DOMAIN_SEPARATOR​

function DOMAIN_SEPARATOR() external view returns (bytes32)

See {IERC20Permit-DOMAIN_SEPARATOR}.

Returns​

NameTypeDescription
_0bytes32undefined

allowance​

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

See {IERC20-allowance}.

Parameters​

NameTypeDescription
owneraddressundefined
spenderaddressundefined

Returns​

NameTypeDescription
_0uint256undefined

approve​

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

See {IERC20-approve}. NOTE: If amount is the maximum uint256, the allowance is not updated on transferFrom. This is semantically equivalent to an infinite approval. Requirements: - spender cannot be the zero address.

Parameters​

NameTypeDescription
spenderaddressundefined
amountuint256undefined

Returns​

NameTypeDescription
_0boolundefined

balanceOf​

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

See {IERC20-balanceOf}.

Parameters​

NameTypeDescription
accountaddressundefined

Returns​

NameTypeDescription
_0uint256undefined

checkpoints​

function checkpoints(address account, uint32 pos) external view returns (struct ERC20Votes.Checkpoint)

Get the pos-th checkpoint for account.

Parameters​

NameTypeDescription
accountaddressundefined
posuint32undefined

Returns​

NameTypeDescription
_0ERC20Votes.Checkpointundefined

decimals​

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​

NameTypeDescription
_0uint8undefined

decreaseAllowance​

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​

NameTypeDescription
spenderaddressundefined
subtractedValueuint256undefined

Returns​

NameTypeDescription
_0boolundefined

delegate​

function delegate(address delegatee) external nonpayable

Delegate votes from the sender to delegatee.

Parameters​

NameTypeDescription
delegateeaddressundefined

delegateBySig​

function delegateBySig(address delegatee, uint256 nonce, uint256 expiry, uint8 v, bytes32 r, bytes32 s) external nonpayable

Delegates votes from signer to delegatee

Parameters​

NameTypeDescription
delegateeaddressundefined
nonceuint256undefined
expiryuint256undefined
vuint8undefined
rbytes32undefined
sbytes32undefined

delegates​

function delegates(address account) external view returns (address)

Get the address account is currently delegating to.

Parameters​

NameTypeDescription
accountaddressundefined

Returns​

NameTypeDescription
_0addressundefined

getPastTotalSupply​

function getPastTotalSupply(uint256 blockNumber) external view returns (uint256)

Retrieve the totalSupply at the end of blockNumber. Note, this value is the sum of all balances. It is but NOT the sum of all the delegated votes! Requirements: - blockNumber must have been already mined

Parameters​

NameTypeDescription
blockNumberuint256undefined

Returns​

NameTypeDescription
_0uint256undefined

getPastVotes​

function getPastVotes(address account, uint256 blockNumber) external view returns (uint256)

Retrieve the number of votes for account at the end of blockNumber. Requirements: - blockNumber must have been already mined

Parameters​

NameTypeDescription
accountaddressundefined
blockNumberuint256undefined

Returns​

NameTypeDescription
_0uint256undefined

getVotes​

function getVotes(address account) external view returns (uint256)

Gets the current votes balance for account

Parameters​

NameTypeDescription
accountaddressundefined

Returns​

NameTypeDescription
_0uint256undefined

increaseAllowance​

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​

NameTypeDescription
spenderaddressundefined
addedValueuint256undefined

Returns​

NameTypeDescription
_0boolundefined

name​

function name() external view returns (string)

Returns the name of the token.

Returns​

NameTypeDescription
_0stringundefined

nonces​

function nonces(address owner) external view returns (uint256)

See {IERC20Permit-nonces}.

Parameters​

NameTypeDescription
owneraddressundefined

Returns​

NameTypeDescription
_0uint256undefined

numCheckpoints​

function numCheckpoints(address account) external view returns (uint32)

Get number of checkpoints for account.

Parameters​

NameTypeDescription
accountaddressundefined

Returns​

NameTypeDescription
_0uint32undefined

permit​

function permit(address owner, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) external nonpayable

See {IERC20Permit-permit}.

Parameters​

NameTypeDescription
owneraddressundefined
spenderaddressundefined
valueuint256undefined
deadlineuint256undefined
vuint8undefined
rbytes32undefined
sbytes32undefined

symbol​

function symbol() external view returns (string)

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

Returns​

NameTypeDescription
_0stringundefined

totalSupply​

function totalSupply() external view returns (uint256)

See {IERC20-totalSupply}.

Returns​

NameTypeDescription
_0uint256undefined

transfer​

function transfer(address to, uint256 amount) external nonpayable returns (bool)

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

Parameters​

NameTypeDescription
toaddressundefined
amountuint256undefined

Returns​

NameTypeDescription
_0boolundefined

transferFrom​

function transferFrom(address from, address to, 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}. NOTE: Does not update the allowance if the current allowance is the maximum uint256. Requirements: - from and to cannot be the zero address. - from must have a balance of at least amount. - the caller must have allowance for from's tokens of at least amount.

Parameters​

NameTypeDescription
fromaddressundefined
toaddressundefined
amountuint256undefined

Returns​

NameTypeDescription
_0boolundefined

Events​

Approval​

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

Parameters​

NameTypeDescription
owner indexedaddressundefined
spender indexedaddressundefined
valueuint256undefined

DelegateChanged​

event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate)

Parameters​

NameTypeDescription
delegator indexedaddressundefined
fromDelegate indexedaddressundefined
toDelegate indexedaddressundefined

DelegateVotesChanged​

event DelegateVotesChanged(address indexed delegate, uint256 previousBalance, uint256 newBalance)

Parameters​

NameTypeDescription
delegate indexedaddressundefined
previousBalanceuint256undefined
newBalanceuint256undefined

Transfer​

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

Parameters​

NameTypeDescription
from indexedaddressundefined
to indexedaddressundefined
valueuint256undefined