标签:Function function uint256 transfer bytes selector Soldity0.8 address Selector
When a function is called, the first 4 bytes of calldata
specifies which function to call.
This 4 bytes is called a function selector.
Take for example, this code below. It uses call
to execute transfer
on a contract at the address addr
.
addr.call(abi.encodeWithSignature("transfer(address,uint256)", 0xSomeAddress, 123))
The first 4 bytes returned from abi.encodeWithSignature(....)
is the function selector.
Perhaps you can save a tiny amount of gas if you precompute and inline the function selector in your code?
Here is how the function selector is computed.
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;
contract FunctionSelector {
/*
"transfer(address,uint256)"
0xa9059cbb
"transferFrom(address,address,uint256)"
0x23b872dd
*/
function getSelector(string calldata _func) external pure returns (bytes4) {
return bytes4(keccak256(bytes(_func)));
}
}
标签:Function,function,uint256,transfer,bytes,selector,Soldity0.8,address,Selector 来源: https://www.cnblogs.com/zaleswift/p/16538402.html
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