Comment by seanmcdirmid
13 years ago
> True, but C++ does not and you still have the performance penalty of reference counting.
Not very relevant. For UI code, responsive resource allocation and de-allocation is much more important than saving a few % CPU cycles.
> Actually, are you aware that reference counting tends to be presented on the first chapter of many CS books about garbage collection as poor man's GC?
Yes! Sometimes the conventional wisdom doesn't hold in the end, or it doesn't hold for all use cases. But I should have been more clear that ref counting is GC, whereas what I refer to as GC involves sweeping reference roots periodically to identify garbage.
> > True, but C++ does not and you still have the performance penalty of reference counting.
> Not very relevant. For UI code, responsive resource allocation and de-allocation is much more important than saving a few % CPU cycles.
I beg to differ. I consider missile control radar systems of military applications a bit more important than UIs.
There are military applications using real time GC systems, which I can list here if you want.
I also have a German magazine here (Making Games Magazin 1/13) that explains how Witcher2 for the Xbox 360 makes use of a GC.
Anyway one thing I do agree, automatic memory management, regardless of the form, should be the any of any programming language.
Pure manual memory management should be treated like Assembly. It will never go away and should only be used for the very few cases where there is no other way around the problem at hand.
I'm not anti-GC, I just think that reference counting is appropriate for UI code. .NET still supports GC, and the collector is very good compared to our competitors; I'm not saying we should give that up!
I should have mentioned that the primary reason WinRT seems to use reference counting is for interop reasons: its much easier to great a UI toolkit that is programmable in both C# and C++. Note that WPF never had a C++ interface, while WinRT has one without the need for any bridge code.
Reference counting has some interesting applications where it is more appropriate trace-based GC. Heck, sometimes we want old-fashioned arenas (Pascal!), it would be nice if our languages could give us some choices.
Manual memory management is annoying but sometimes necessary. I can see why native programmers don't want to give it up as it constitutes the primary performance difference these days between native and managed languages.