CODEWITHSUNDEEP
language-agnosticrecursionoperating-system
anand
anand

Reputation: 11339

What will happen if function goes out of stack space during infinite recursion?

There is a function that calls itself recursively infinitely.

This function has some arguments too.

For every function call the arguments and return address are pushed on the stack .

For each process there is fixed size of stack space that cannot grow dynamically like heap. And I guess each thread also has its own stack.

Now if a function is called recursively infinitely and process runs out of stack space , what will happen?

Will program crash? Will OS handle the situation? There is 4GB of address space so why cannot OS do something to increase stack size.

Upvotes: 1

Views: 4042

Answers (8)

vartec
vartec

Reputation: 134641

stack overflow.

In UNIX and compatible the process will get terminated throwing SIGSEGV or SIGSTKFLT signal.

In Windows the process will get terminated throwing exception STATUS_STACK_OVERFLOW.

Upvotes: 6

Jens Schauder
Jens Schauder

Reputation: 82000

There are plenty of answers what will happen, but I want to mention the extremely easy solution:

Just by a turing machine and let your code run on that. It will have plenty of space.

Upvotes: 0

Jon Skeet
Jon Skeet

Reputation: 1502486

This isn't language-agnostic - it very much depends on the language/platform.

In C# (or any .NET language) you'll get a StackOverflowException, which as of .NET 2.0 cannot be caught and will bring down the process.

In Java (or any JVM language) you'll get a StackOverflowError (as specified here).

I'll leave it to other answers to deal with other languages and platforms :)

Upvotes: 2

T.E.D.
T.E.D.

Reputation: 44804

Yes, your program will crash. There is no way for the OS to "handle the situation", other than preventing your buggy code from damaging other processes (which it is already doing). The OS has no way of knowing what it was you really wanted your program to do, rather than what you told it to do.

Upvotes: 0

starblue
starblue

Reputation: 56802

Depending on the language you will either get an exception (e.g. in Java) or the program will crash (in C, C++).

Typically the stack is relatively small, because that suffices, and a stack overflow signals an error. In Java you can increase the stack space with a command line option if you must.

Also note that functional languages typically compile tail recursion into a loop, and no stack space is used in that case.

Upvotes: 2

Leonard
Leonard

Reputation: 13767

A typical Unix result will be a segmentation fault. Don't know about Windows.

Upvotes: 0

anon
anon

Reputation:

For C++ at least, you will be in the realms of "undefined behaviour" - a bit like the Twilight Zone, anything could happen.

And if the recursion is infinite, what good will increasing the stack size do? Better to fail early than later.

Upvotes: 2

Antti Huima
Antti Huima

Reputation: 25542

The program will crash. Usually stack is limited by operating systems in order to trap bugs like this before they consume ALL available memory. On Linux at least the stack size can be changed by the user by issuing the limit command in shell.

Upvotes: -1

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