o prevent reentrancy in smart contracts, always use the Checks-Effects-Interactions pattern, where state changes (e.g., updating balances) are performed before any external calls; use ReentrancyGuard from OpenZeppelin, which provides a non-reentrant modifier to block nested calls; ensure minimal reliance on external calls, and if unavoidable, use call instead of transfer or send while implementing gas limits; validate inputs and set proper access controls to avoid unauthorized access; maintain variables to track whether a function is already in execution, often through a bool lock mechanism; prefer pull-over-push designs for withdrawals to minimize external dependency; and regularly audit code and stay updated on known vulnerabilities to strengthen defenses.
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