SafeERC20

Wrappers around ERC-20 operations that throw on failure (when the token contract returns false). Tokens that return no value (and instead revert or throw on failure) are also supported, non-reverting calls are assumed to be successful. To use this library you can add a using SafeERC20 for IERC20; statement to your contract, which allows you to call the safe operations as token.safeTransfer(...), etc.

Functions

safeTransfer

Transfer value amount of token from the calling contract to to. If token returns no value, non-reverting calls are assumed to be successful.

function safeTransfer(IERC20 token, address to, uint256 value) internal;

safeTransferFrom

Transfer value amount of token from from to to, spending the approval given by from to the calling contract. If token returns no value, non-reverting calls are assumed to be successful.

function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal;

trySafeTransfer

Variant of safeTransfer that returns a bool instead of reverting if the operation is not successful.

function trySafeTransfer(IERC20 token, address to, uint256 value) internal returns (bool);

trySafeTransferFrom

Variant of safeTransferFrom that returns a bool instead of reverting if the operation is not successful.

function trySafeTransferFrom(IERC20 token, address from, address to, uint256 value) internal returns (bool);

safeIncreaseAllowance

Increase the calling contract's allowance toward spender by value. If token returns no value, non-reverting calls are assumed to be successful. IMPORTANT: If the token implements ERC-7674 (ERC-20 with temporary allowance), and if the "client" smart contract uses ERC-7674 to set temporary allowances, then the "client" smart contract should avoid using this function. Performing a safeIncreaseAllowance or {safeDecreaseAllowance} operation on a token contract that has a non-zero temporary allowance (for that particular owner-spender) will result in unexpected behavior.

function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal;

safeDecreaseAllowance

Decrease the calling contract's allowance toward spender by requestedDecrease. If token returns no value, non-reverting calls are assumed to be successful. IMPORTANT: If the token implements ERC-7674 (ERC-20 with temporary allowance), and if the "client" smart contract uses ERC-7674 to set temporary allowances, then the "client" smart contract should avoid using this function. Performing a safeIncreaseAllowance or {safeDecreaseAllowance} operation on a token contract that has a non-zero temporary allowance (for that particular owner-spender) will result in unexpected behavior.

function safeDecreaseAllowance(IERC20 token, address spender, uint256 requestedDecrease) internal;

forceApprove

Set the calling contract's allowance toward spender to value. If token returns no value, non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval to be set to zero before setting it to a non-zero value, such as USDT. NOTE: If the token implements ERC-7674, this function will not modify any temporary allowance. This function only sets the "standard" allowance. Any temporary allowance will remain active, in addition to the value being set here.

function forceApprove(IERC20 token, address spender, uint256 value) internal;

transferAndCallRelaxed

Performs an {ERC1363} transferAndCall, with a fallback to the simple {ERC20} transfer if the target has no code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when targeting contracts. Reverts if the returned value is other than true.

function transferAndCallRelaxed(IERC1363 token, address to, uint256 value, bytes memory data) internal;

transferFromAndCallRelaxed

Performs an {ERC1363} transferFromAndCall, with a fallback to the simple {ERC20} transferFrom if the target has no code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when targeting contracts. Reverts if the returned value is other than true.

function transferFromAndCallRelaxed(IERC1363 token, address from, address to, uint256 value, bytes memory data)
    internal;

approveAndCallRelaxed

Performs an {ERC1363} approveAndCall, with a fallback to the simple {ERC20} approve if the target has no code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when targeting contracts. NOTE: When the recipient address (to) has no code (i.e. is an EOA), this function behaves as {forceApprove}. Opposedly, when the recipient address (to) has code, this function only attempts to call {ERC1363-approveAndCall} once without retrying, and relies on the returned value to be true. Reverts if the returned value is other than true.

function approveAndCallRelaxed(IERC1363 token, address to, uint256 value, bytes memory data) internal;

_callOptionalReturn

Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement on the return value: the return value is optional (but if data is returned, it must not be false).

function _callOptionalReturn(IERC20 token, bytes memory data) private;

Parameters

_callOptionalReturnBool

Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement on the return value: the return value is optional (but if data is returned, it must not be false).

function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool);

Parameters

Errors

SafeERC20FailedOperation

An operation with an ERC-20 token failed.

error SafeERC20FailedOperation(address token);

SafeERC20FailedDecreaseAllowance

Indicates a failed decreaseAllowance request.

error SafeERC20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);