Blockchain Developer's Guide

Function modifiers

Function modifiers can be used to amend the semantics of functions in a declaration. That is, they are used to change the behavior of a function. For example, they are used to automatically check a condition before executing the function, or they can unlock a function at a given timeframe as required. They can be overwritten by derived contracts, as shown here:

pragma solidity ^0.4.24;contract Gotham { address public weapons;modifier Bank() { // Modifier require(     msg.sender == coins,     "Only coins can call this."     );     _; }    function abort() public coinsbuyer { // Modifier usage // ... }}