Why are stackoverflow errors chaotic?

Question

This simple C program rarely terminates at the same call depth:

#include 
#include 

void recursive(unsigned int rec);

int ma         


        

Answer 1

The above code can cause two issue:

• Stack Overflow.
• Integer overflow.

Stack Overflow: When a recursive function is called, all its variable is pushed onto the call stack including its return address. As there is no base condition which will terminate the recursion and the stack memory is limited, the stack will exhausted resulting Stack Overflow exception. The call stack may consist of a limited amount of address space, often determined at the start of the program. The size of the call stack depends on many factors, including the programming language, machine architecture, multi-threading, and amount of available memory. When a program attempts to use more space than is available on the call stack (that is, when it attempts to access memory beyond the call stack's bounds, which is essentially a buffer overflow), the stack is said to overflow, typically resulting in a program crash.

Note that, every time a function exits/return, all of the variables pushed onto the stack by that function, are freed (that is to say, they are deleted). Once a stack variable is freed, that region of memory becomes available for other stack variables. But for recursive function, the return address are still on the stack until the recursion terminates. Moreover, automatic local variables are allocated as a single block and stack pointer advanced far enough to account for the sum of their sizes. You maybe interested at Recursive Stack in C.

Integer overflow: As every recursive call of recursive() increments rec by 1, there is a chance that Integer Overflow can occur. For that, you machine must have a huge stack memory as the range of unsigned integer is: 0 to 4,294,967,295. See reference here.