---
title: Invalid variable-length array
framework: xcode
role: article
role_heading: Article
path: xcode/invalid-variable-length-array
---

# Invalid variable-length array

Detects negative array bounds.

## Overview

Overview Use this check to detect negative array bounds. Variable-length arrays with a negative length have undefined behavior, and may cause stack corruption. Available in Xcode 9 and later. Negative variable-length array bounds in C In the following code, the call to the invalid_index_returning_function function returns a negative number that results in an invalid array: int invalid_index_returning_function() {     return -1; } int idx = invalid_index_returning_function(); int array[idx]; // Error: invalid array length Solution Fix the issue by checking array bounds before constructing arrays.

## See Also

### Undefined Behavior Sanitizer

- [Misaligned pointer](xcode/misaligned-pointer.md)
- [Invalid Boolean value](xcode/invalid-boolean.md)
- [Out-of-bounds array access](xcode/out-of-bounds-array-access.md)
- [Invalid enumeration value](xcode/invalid-enumeration-value.md)
- [Reaching of unreachable point](xcode/reaching-of-unreachable-point.md)
- [Dynamic type violation](xcode/dynamic-type-violation.md)
- [Invalid float cast](xcode/invalid-float-cast.md)
- [Division by zero](xcode/division-by-zero.md)
- [Nonnull argument violation](xcode/nonnull-argument-violation.md)
- [Nonnull return value violation](xcode/nonnull-return-value-violation.md)
- [Nonnull variable assignment violation](xcode/nonnull-variable-assignment-violation.md)
- [Null reference creation and null pointer dereference](xcode/null-reference-creation-and-null-pointer-dereference.md)
- [Invalid object size](xcode/invalid-object-size.md)
- [Invalid shift](xcode/invalid-shift.md)
- [Integer overflow](xcode/integer-overflow.md)