• (ERC20.sol)

View Source: openzeppelin-solidity/contracts/token/ERC20/ERC20.sol​

↗ Extends: IERC20 ↘ Derived Contracts: SecurityToken​

ERC20

Implementation of the basic standard token. https://eips.ethereum.org/EIPS/eip-20 Originally based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol​

• This implementation emits additional Approval events, allowing applications to reconstruct the allowance status for

  all accounts just by listening to said events. Note that this isn't required by the specification, and other

  compliant implementations may not do it.

Contract Members

Constants & Variables

mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowed;
uint256 private _totalSupply;

Functions

• ​totalSupply()​

• ​balanceOf(address owner)​

• ​allowance(address owner, address spender)​

• ​transfer(address to, uint256 value)​

• ​approve(address spender, uint256 value)​

• ​transferFrom(address from, address to, uint256 value)​

• ​increaseAllowance(address spender, uint256 addedValue)​

• ​decreaseAllowance(address spender, uint256 subtractedValue)​

• ​_transfer(address from, address to, uint256 value)​

• ​_mint(address account, uint256 value)​

• ​_burn(address account, uint256 value)​

• ​_approve(address owner, address spender, uint256 value)​

• ​_burnFrom(address account, uint256 value)​

totalSupply

⤾ overrides IERC20.totalSupply​

Total number of tokens in existence

function totalSupply() public view
returns(uint256)

Arguments

balanceOf

⤾ overrides IERC20.balanceOf​

Gets the balance of the specified address.

function balanceOf(address owner) public view
returns(uint256)

Returns

A uint256 representing the amount owned by the passed address.

Arguments

allowance

⤾ overrides IERC20.allowance​

Function to check the amount of tokens that an owner allowed to a spender.

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

Returns

A uint256 specifying the amount of tokens still available for the spender.

Arguments

transfer

⤾ overrides IERC20.transfer​

⤿ Overridden Implementation(s): SecurityToken.transfer​

Transfer token to a specified address

function transfer(address to, uint256 value) public nonpayable
returns(bool)

Arguments

approve

⤾ overrides IERC20.approve​

Approve the passed address to spend the specified amount of tokens on behalf of msg.sender. Beware that changing an allowance with this method brings the risk that someone may use both the old and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards: https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729​

function approve(address spender, uint256 value) public nonpayable
returns(bool)

Arguments

transferFrom

⤾ overrides IERC20.transferFrom​

⤿ Overridden Implementation(s): SecurityToken.transferFrom​

Transfer tokens from one address to another. Note that while this function emits an Approval event, this is not required as per the specification, and other compliant implementations may not emit the event.

function transferFrom(address from, address to, uint256 value) public nonpayable
returns(bool)

Arguments

increaseAllowance

Increase the amount of tokens that an owner allowed to a spender. approve should be called when _allowed[msg.sender][spender] == 0. To increment allowed value is better to use this function to avoid 2 calls (and wait until the first transaction is mined) From MonolithDAO Token.sol Emits an Approval event.

function increaseAllowance(address spender, uint256 addedValue) public nonpayable
returns(bool)

Arguments

decreaseAllowance

Decrease the amount of tokens that an owner allowed to a spender. approve should be called when _allowed[msg.sender][spender] == 0. To decrement allowed value is better to use this function to avoid 2 calls (and wait until the first transaction is mined) From MonolithDAO Token.sol Emits an Approval event.

function decreaseAllowance(address spender, uint256 subtractedValue) public nonpayable
returns(bool)

Arguments

_transfer

Transfer token for a specified addresses

function _transfer(address from, address to, uint256 value) internal nonpayable

Arguments

_mint

Internal function that mints an amount of the token and assigns it to an account. This encapsulates the modification of balances such that the proper events are emitted.

function _mint(address account, uint256 value) internal nonpayable

Arguments

_burn

Internal function that burns an amount of the token of a given account.

function _burn(address account, uint256 value) internal nonpayable

Arguments

_approve

Approve an address to spend another addresses' tokens.

function _approve(address owner, address spender, uint256 value) internal nonpayable

Arguments

_burnFrom

Internal function that burns an amount of the token of a given account, deducting from the sender's allowance for said account. Uses the internal burn function. Emits an Approval event (reflecting the reduced allowance).

function _burnFrom(address account, uint256 value) internal nonpayable

Arguments