Solidity API

IERC20

_Interface of the ERC20 standard as defined in EIP-20. This interface defines the standard functions that an ERC20 token contract should implement. All functions must revert on failure rather than return false. See https://eips.ethereum.org/EIPS/eip-20_

totalSupply

function totalSupply() external view returns (uint256)

Returns the total number of tokens in existence

This value includes all minted tokens minus all burned tokens. The returned value may change due to minting or burning events.

Return Values

Name	Type	Description
[0]	uint256	The total supply of tokens

balanceOf

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

Returns the token balance of a given account

The balance can change due to transfers, mints, or burns. Zero address query should return 0.

Parameters

Name	Type	Description
account	address	The address for which to query the balance

Return Values

Name	Type	Description
[0]	uint256	The number of tokens owned by the account

allowance

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

Returns the remaining number of tokens that spender is allowed to spend on behalf of holder

Zero address queries should return 0. If no approval exists, should return 0. Value may change due to spend or additional approve calls.

Parameters

Name	Type	Description
holder	address	The address which owns the tokens
spender	address	The address which is approved to spend the tokens

Return Values

Name	Type	Description
[0]	uint256	The number of tokens still available for the spender to spend

approve

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

Sets the amount of tokens that spender is allowed to spend on behalf of the caller

_IMPORTANT: Beware of race conditions - subsequent calls to this function override the current allowance. Use increaseAllowance/decreaseAllowance from ERC20Extended instead. Must emit Approval event. Should revert if:

• spender is zero address
• insufficient balance_

Parameters

Name	Type	Description
spender	address	The address which will be approved to spend tokens
amount	uint256	The number of tokens to be approved for spending

Return Values

Name	Type	Description
[0]	bool	Always returns true (function should revert on failure)

transfer

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

Moves tokens from caller's account to the recipient

_Must emit Transfer event. Should revert if:

• recipient is zero address
• sender has insufficient balance
• transfer amount exceeds sender's balance_

Parameters

Name	Type	Description
recipient	address	The address which will receive the tokens
amount	uint256	The number of tokens to transfer

Return Values

Name	Type	Description
[0]	bool	Always returns true (function should revert on failure)

transferFrom

function transferFrom(address holder, address recipient, uint256 amount) external returns (bool)

Moves tokens from holder's account to recipient using the allowance mechanism

_Must emit Transfer event. Must emit Approval event if allowance is updated. Should revert if:

• holder or recipient is zero address
• holder has insufficient balance
• spender has insufficient allowance
• transfer amount exceeds holder's balance or spender's allowance_

Parameters

Name	Type	Description
holder	address	The address which owns the tokens to be transferred
recipient	address	The address which will receive the tokens
amount	uint256	The number of tokens to transfer

Return Values

Name	Type	Description
[0]	bool	Always returns true (function should revert on failure)