Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
599 views
in Technique[技术] by (71.8m points)

objective c - Generic typeof for weak self references

I am trying to figure out a way to use typeof to create a weak reference to self for use in blocks to avoid retain cycles.

When I first read about this it seems that the convention was to use __block typeof(self) bself = self;, which compiles but using __block to avoid retain cycles doesn't work anymore and __weak should be used instead.

However __weak typeof(self) bself = self; results in an error:

The type 'typeof (self)' (aka 'TUAccountsViewController *const __strong') already has retainment attributes set on it

Is there a way to use typeof or another call to generically create a weak reference to self?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

In the latest clang version Apple clang version 4.0 (tags/Apple/clang-421.1.48) (based on LLVM 3.1svn), i.e. Xcode 4.4+, the __typeof__((__typeof__(self))self) trick is not necessary anymore. The __weak typeof(self) bself = self; line will compile just fine.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

2.1m questions

2.1m answers

60 comments

57.0k users

...