`StackOverflowException`

The stack has limited memory. It can overflow. Typically the StackOverflowException is triggered by a recursive method that creates a deep call stack.

Nested methods

Basically any program that has deeply-nested calls, such as a recursive call, is at risk of a StackOverflowException. The size of the stack depends on the operating system.

Example

This program defines a method that causes an infinite recursion at runtime. The Recursive() method calls itself at the end of each invocation.

However The current C# compiler does not achieve this. Each method call frame (activation record) is kept on the stack memory.

And After nearly 80,000 invocations, the stack memory space is exhausted and the program terminates.

Info Usually, the StackOverflowException is caused by an infinite or uncontrolled recursion.

using System;

class Program
{
    static void Recursive(int value)
    {
        // Write call number and call this method again.
        // ... The stack will eventually overflow.
        Console.WriteLine(value);
        Recursive(++value);
    }

    static void Main()
    {
        // Begin the infinite recursion.
        Recursive(0);
    }
}79845
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Process is terminated due to StackOverflowException.

`Exception` message

The message "Process is terminated" is displayed. If you wrap the initial call to Recursive in a try-catch block, you cannot catch the StackOverflowException.

`Tail` recursion

The Recursive method body here contains a single call to the same method in its final statement. This could be rewritten as a linear loop.

And Such a loop could continue indefinitely because it requires constant space on the stack.

But The C# compiler was unable to apply this optimization, called tail recursion, in this program.

Summary

We tested a program that creates an infinite recursion to demonstrate the StackOverflowException. This exception is a risk to all programs—even those that do not use recursion.

StackOverflowException