# V2598\. MISRA\. Variable length array types are not allowed\.

This diagnostic rule is based on the [MISRA](https://www.misra.org.uk/) \(Motor Industry Software Reliability Association\) manual for software development\.

This rule only applies to C\. Declaring variable\-length arrays can lead to a stack overflow and potential vulnerabilities in the program\.

Look at the example:

```cpp
void foo(size_t n)
{
  int arr[n];
  // ....
}
```

Transmission of large number 'n' can lead to a stack overflow as the array will become too large and take up more memory than it really is\.

The most logical way is to limit the size of the array:

```cpp
#define MAX_SIZE 128
void foo(size_t n)
{
  size_t size = n > MAX_SIZE ? MAX_SIZE : n;
  int arr[size];
  if (size < n) // error
  // ....
}
```

However, in this case it is better to use a constant to simplify the logic of the program:

```cpp
#define SIZE 128
void foo()
{
  int arr[size];
  // ....
}
```

This will also help to avoid VLA\-connected problems like calculating 'sizeof' on such arrays and passing them to other functions\.