IButtonswapERC20
Inherits: IButtonswapERC20Errors, IButtonswapERC20Events
Functions
name
Returns the name of the token.
function name() external view returns (string memory _name);
Returns
Name | Type | Description |
---|---|---|
_name | string | The token name |
symbol
Returns the symbol of the token, usually a shorter version of the name.
function symbol() external view returns (string memory _symbol);
Returns
Name | Type | Description |
---|---|---|
_symbol | string | The token symbol |
decimals
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
).
This information is only used for display purposes: it in no way affects any of the arithmetic of the contract.
function decimals() external pure returns (uint8 decimals);
Returns
Name | Type | Description |
---|---|---|
decimals | uint8 | The number of decimals |
totalSupply
Returns the amount of tokens in existence.
function totalSupply() external view returns (uint256 totalSupply);
Returns
Name | Type | Description |
---|---|---|
totalSupply | uint256 | The amount of tokens in existence |
balanceOf
Returns the amount of tokens owned by account
.
function balanceOf(address owner) external view returns (uint256 balance);
Parameters
Name | Type | Description |
---|---|---|
owner | address | The account the balance is being checked for |
Returns
Name | Type | Description |
---|---|---|
balance | uint256 | The amount of tokens owned by owner |
allowance
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.
function allowance(address owner, address spender) external view returns (uint256 allowance);
Parameters
Name | Type | Description |
---|---|---|
owner | address | The account that owns the tokens |
spender | address | The account that can spend the tokens |
Returns
Name | Type | Description |
---|---|---|
allowance | uint256 | The amount of tokens owned by owner that the spender can transfer |
approve
Sets value
as the allowance of spender
over the caller's tokens.
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 {IButtonswapERC20Events-Approval} event.
function approve(address spender, uint256 value) external returns (bool success);
Parameters
Name | Type | Description |
---|---|---|
spender | address | The account that is granted permission to spend the tokens |
value | uint256 | The amount of tokens that can be spent |
Returns
Name | Type | Description |
---|---|---|
success | bool | Whether the operation succeeded |
transfer
Moves value
tokens from the caller's account to to
.
Emits a {IButtonswapERC20Events-Transfer} event.
function transfer(address to, uint256 value) external returns (bool success);
Parameters
Name | Type | Description |
---|---|---|
to | address | The account that is receiving the tokens |
value | uint256 | The amount of tokens being sent |
Returns
Name | Type | Description |
---|---|---|
success | bool | Whether the operation succeeded |
transferFrom
Moves value
tokens from from
to to
using the allowance mechanism.
value
is then deducted from the caller's allowance.
Emits a {IButtonswapERC20Events-Transfer} event.
function transferFrom(address from, address to, uint256 value) external returns (bool);
Parameters
Name | Type | Description |
---|---|---|
from | address | The account that is sending the tokens |
to | address | The account that is receiving the tokens |
value | uint256 | The amount of tokens being sent |
Returns
Name | Type | Description |
---|---|---|
<none> | bool | success Whether the operation succeeded |
DOMAIN_SEPARATOR
Returns the domain separator used in the encoding of the signature for {permit}, as defined by EIP712.
function DOMAIN_SEPARATOR() external view returns (bytes32 DOMAIN_SEPARATOR);
Returns
Name | Type | Description |
---|---|---|
DOMAIN_SEPARATOR | bytes32 | The DOMAIN_SEPARATOR value |
PERMIT_TYPEHASH
Returns the typehash used in the encoding of the signature for {permit}, as defined by EIP712.
function PERMIT_TYPEHASH() external pure returns (bytes32 PERMIT_TYPEHASH);
Returns
Name | Type | Description |
---|---|---|
PERMIT_TYPEHASH | bytes32 | The PERMIT_TYPEHASH value |
nonces
Returns the current nonce for owner
.
This value must be included whenever a signature is generated for {permit}.
Every successful call to {permit} increases owner
's nonce by one.
This prevents a signature from being used multiple times.
function nonces(address owner) external view returns (uint256 nonce);
Parameters
Name | Type | Description |
---|---|---|
owner | address | The account to get the nonce for |
Returns
Name | Type | Description |
---|---|---|
nonce | uint256 | The current nonce for the given owner |
permit
Sets value
as the allowance of spender
over owner
's tokens, given owner
's signed approval.
*IMPORTANT: The same issues {approve} has related to transaction ordering also apply here. Emits an {IButtonswapERC20Events-Approval} event. Requirements:
spender
cannot be the zero address.deadline
must be a timestamp in the future.v
,r
ands
must be a validsecp256k1
signature fromowner
over the EIP712-formatted function arguments.- the signature must use
owner
's current nonce (see {nonces}). For more information on the signature format, see the relevant EIP section.*
function permit(address owner, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s)
external;
Parameters
Name | Type | Description |
---|---|---|
owner | address | The account that owns the tokens |
spender | address | The account that can spend the tokens |
value | uint256 | The amount of owner 's tokens that spender can transfer |
deadline | uint256 | The future time after which the permit is no longer valid |
v | uint8 | Part of the signature |
r | bytes32 | Part of the signature |
s | bytes32 | Part of the signature |