examples/solidity-custom-modifiers

CustomModifiers.sol

pragma solidity >=0.5.0;

contract CustomModifiers {

    // State variable
    address private owner;

	// Custom modifier requiring that the sender of the transaction is the owner
	// otherwise revert the transaction
    modifier onlyOwner {
        require(msg.sender == owner, "Only owner can call this function.");
        _;
    }

	// Constructor takes an address and stores it in the owner variable
    constructor(address _owner) public {
        owner = _owner;
    }

	// someFunction() uses the onlyOwner modifier to make use of our
	// custom definition on line 10
    function someFunction() external onlyOwner { 
        ...
    }
}