Skip to main content

IERC20Standard

IERC20Standard#

Functions#

decimals() → uint8 (external)

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}.

totalSupply() → uint256 (external)

Returns the amount of tokens in existence.

balanceOf(address account) → uint256 (external)

Returns the amount of tokens owned by account.

transfer(address recipient, uint256 amount) → bool (external)

Moves amount tokens from the caller's account to recipient. Returns a boolean value indicating whether the operation succeeded. Emits a {Transfer} event.

allowance(address owner, address spender) → uint256 (external)

Returns the remaining number of tokens that spender will be allowed to spend on behalf of owner through {transferFrom}. This is zero by default. This value changes when {approve} or {transferFrom} are called.

approve(address spender, uint256 amount) → bool (external)

Sets amount as the allowance of spender over the caller's tokens. Returns a boolean value indicating whether the operation succeeded. IMPORTANT: 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 Emits an {Approval} event.

transferFrom(address sender, address recipient, uint256 amount) → bool (external)

Moves amount tokens from sender to recipient using the allowance mechanism. amount is then deducted from the caller's allowance. Returns a boolean value indicating whether the operation succeeded. Emits a {Transfer} event.

Events#

Transfer(address from, address to, uint256 value)

Emitted when value tokens are moved from one account (from) to another (to). Note that value may be zero.

Approval(address owner, address spender, uint256 value)

Emitted when the allowance of a spender for an owner is set by a call to {approve}. value is the new allowance.