How Can a Reentrancy Guard Modifier Offer a Simpler Alternative to This Pattern?

A reentrancy guard is a modifier that can be applied to functions in a smart contract. It typically uses a boolean locking variable, such as isLocked , which is set to true at the beginning of a function's execution.

If the function is re-entered while isLocked is true , the transaction reverts. The variable is then set back to false at the end of the function's execution.

This provides a simple and effective way to prevent reentrancy attacks without needing to manually order checks, effects, and interactions in every function.