• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
SonicD007

How does C# handle pointers internally?

4 posts in this topic

Hey everyone,

I was refreshing on my pointer skills by reading about linked lists and it got me wondering how C# handles it's lists. Lets say I have a global list of type Foo
[code]
List<Foo> globalList = new List<Foo>();
[/code]
Now lets say I create an instantiate a Foo object within a local scope of a function.

[code]
void LocalFunction()
{
Foo myLocalObject = new myLocalObject();
//Do stuff with myLocalObject
globalList.Add(myLocalObject);
}
[/code]

From what I understand with c++, globalList.Add(myLocalObject); is passing the object by address (which is how c# passes classes anyway) so even though myLocalObject is no longer in scope, I can still access it and it's information by using globalList[whateverIndexItsat].whateverMethod();

I'm able to do this because C# has a pointer internally somewhere in which it is pointing to the memory created by that localObject. Is my understanding of this correct? Also, does the garbage collector manage the pointers by reference counting?

I'm just curious as to how everything is working here and the linked list datastructure in C++ is helping me understand where to use pointers a little better.

Thanks, hopefully I'm understanding this correctly.
0

Share this post


Link to post
Share on other sites
[url=http://msdn.microsoft.com/en-us/library/0xy59wtx.aspx].NET Garbage Collection[/url] is significantly more sophisticated than just reference counting.
0

Share this post


Link to post
Share on other sites
Pointers internally [url="http://msdn.microsoft.com/en-us/magazine/cc163791.aspx"]are pretty complicated too[/url].

The linked article is rather dated, it covers .NET 1.1 after all, but the basics of memory management are all there.
0

Share this post


Link to post
Share on other sites
Here is some more good reading on the subject of references and pointers in C#. Not necessarily directly related to your question, but good reading on the topics, nonetheless.

[url="http://blogs.msdn.com/b/ericlippert/archive/2009/02/17/references-are-not-addresses.aspx"]http://blogs.msdn.com/b/ericlippert/archive/2009/02/17/references-are-not-addresses.aspx[/url]
[url="http://blogs.msdn.com/b/ericlippert/archive/2011/03/07/references-and-pointers-part-one.aspx"]http://blogs.msdn.com/b/ericlippert/archive/2011/03/07/references-and-pointers-part-one.aspx[/url]
[url="http://blogs.msdn.com/b/ericlippert/archive/2011/03/10/references-and-pointers-part-two.aspx"]http://blogs.msdn.com/b/ericlippert/archive/2011/03/10/references-and-pointers-part-two.aspx[/url]

A slight aside, List<T> in C# is more analogous to std::vector in C++. It's not a linked list; it's just an indexable collection of objects. Generally speaking a List<T> in C# is just implemented as a raw T[] under the hood, handling resizing the array as necessary. If you wanted a linked list there is the aptly named [url="http://msdn.microsoft.com/en-us/library/he2s3bh7.aspx"]LinkedList<T>[/url] class.
0

Share this post


Link to post
Share on other sites
They aren't "pointers" in C#, they are references. This sounds like a non-important distinction, but it is important because C# has [i]actual pointers[/i] as well.

.NET does not use reference counting, it uses a generational garbage collector where objects are moved along the generations as they are no longer rooted to another non-collected object. You'll hear the terms "anchored" or "rooted" a lot when dealing with this kind of GC. You'll also hear terms like "gen1 object" or "gen2 object", and this just has to do with where in the GC process the object is. Note that this is all true for the reference implementation of the .NET framework. It's quite possible that projects like Mono have their own implementation, though I am almost positive that Mono uses a very similar generational GC.

That said, your understanding of what's going on from a high level is correct. When you put a reference to your object in to that list, the list now holds it's "root" (or one of them anyway, you may have references in other places). The fact that the variable the reference was assigned to is local means nothing. That local variable will fall out of scope, but the reference it was attached to will not be swept by the GC because you have it anchored in that list. Edited by GnomeTank
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0