# ReentrancyGuardUpgradeable







*Contract module that helps prevent reentrant calls to a function. Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier available, which can be applied to functions to make sure there are no nested (reentrant) calls to them. Note that because there is a single `nonReentrant` guard, functions marked as `nonReentrant` may not call one another. This can be worked around by making those functions `private`, and then adding `external` `nonReentrant` entry points to them. TIP: If you would like to learn more about reentrancy and alternative ways to protect against it, check out our blog post https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].*



