# Use of out-of-scope stack memory Detects access to variables outside of their declared scope. ## Overview Use this check to detect when you access a variable outside of its scope. Attempting to access out-of-scope memory can result in unpredictable behavior. Available in Xcode 9 and later. ### Use of out-of-scope stack memory in C In the following example, the code conditionally assigns the `pointer` variable to the return value of the `integer_returning_function` function, which it then accesses out of its declaration scope: ```occ int *pointer = NULL; if (bool_returning_function()) { int value = integer_returning_function(); pointer = &value; } *pointer = 42; // Error: invalid access of stack memory out of declaration scope ``` #### Solution Ensure you don’t access variables outside of their declared scope, or allocate memory using the `malloc` function. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)