How to check empty in solidity

Question

In solidity can we check if(empty) just like we do in php

Or anything equivalent to that. What I want to do is to check if msg.sender trigger the call with empty msg.value or has put some amount to trigger the function

 if (empty(msg.value))

Answer 1

msg.value is a number(uint) is Solidity so it will be >=0, it cannot be empty.