Comments on: Objective-C 2.0 Garbage Collection

By: Benton Sisto

Benton Sisto — Sat, 12 Jun 2010 00:02:39 +0000

Hi there can I use some of the material here in this entry if I reference you with a link back to your site?

By: Objective-C 2.0 Garbage Collection, Part II « Douglas Purdy

Objective-C 2.0 Garbage Collection, Part II « Douglas Purdy — Sat, 14 Jun 2008 08:28:00 +0000

[...] Posted in Apple It turns out I was wrong (it will not be the last time) about the four apps I pegged as possibly using GC in 10.5 here. [...]

By: Mark Rowe

Mark Rowe — Sat, 14 Jun 2008 07:22:09 +0000

I’m not sure how you determined which applications use garbage collection on Leopard, but as best I can tell exactly none of the four applications you list do. However, as Simon Fell mentions Xcode *does* use garbage collection:

mrowe@daisy:~$ otool -oV /Applications/Mail.app/Contents/MacOS/Mail | tail -n3
Contents of (__OBJC,__image_info) section
version 0
flags 0×0 RR
mrowe@daisy:~$ otool -oV /Applications/iChat.app/Contents/MacOS/iChat | tail -n3
Contents of (__OBJC,__image_info) section
version 0
flags 0×0 RR
mrowe@daisy:~$ otool -oV /Applications/Preview.app/Contents/MacOS/Preview | tail -n3
Contents of (__OBJC,__image_info) section
version 0
flags 0×0 RR
mrowe@daisy:~$ otool -oV /Applications/Photo\ Booth.app/Contents/MacOS/Photo\ Booth | tail -n3
Contents of (__OBJC,__image_info) section
version 0
flags 0×0 RR
mrowe@daisy:~$ otool -oV /Developer/Applications/Xcode.app/Contents/MacOS/Xcode | tail -n3
Contents of (__OBJC,__image_info) section
version 0
flags 0×2 GC RR
mrowe@daisy:~$

The field of interest here is the “flags” field of the __image_info section of the __OBJC segment. If garbage collection is supported it will have the value 0×2 and will be shown as “GC RR” to represent that both garbage collection and retain/release are supported. If garbage collection is *required* then the field will have the value 0×4 and will be shown as “GC-only” indicating that only garbage collection is supported and that retain/release is not available. The field can also contain other values, but those two are the only values that are relevant to garbage collection.

By: Simon Fell

Simon Fell — Fri, 13 Jun 2008 02:15:12 +0000

XCode also uses GC

By: » Objective-C 2.0 Garbage Collection A C One: What The World Is Saying About A C One

Thu, 12 Jun 2008 23:35:26 +0000

[...] 2.0 Garbage Collection Posted in June 12th, 2008 by in Uncategorized Objective-C 2.0 Garbage Collection Yesterday I was having a discussion about which Apple apps use the new garbage collection feature [...]

By: Joe

Joe — Thu, 12 Jun 2008 23:28:33 +0000

Right.
MS complain that the uptake of WPF is slow. I put this down to Microsoft not dogfooding the technology more than the tech itself.
Look at AJAX – that was very hard to get right before we had supporting toolkits. It was only when Google demonstrated it in their predictive text search box when it got the real interest of developers.

What happened to Microsoft Max?
Why doesn’t Windows Live Mail etc use WPF?
Why have Yahoo got a Vista IM client written in WPF and MS doesn’t.