[英]Is self retained within this Objective-C block?
When I have a block in Objective-C that looks like this: 当我在Objective-C中有一个块看起来像这样:
self.request = [[ASIHTTPRequest requestWithURL:...
[self.longPollRequest setCompletionBlock:^{
NSLog(@"%@", self.request.responseString);
}];
will it retain self
or explicitly retain self.request
? 它会保留self
还是明确地保留self.request
?
As the Block Programming Topics says: 正如Block Programming Topics所说:
In a reference-counted environment, by default when you reference an Objective-C object within a block, it is retained. 在引用计数环境中,默认情况下,当您引用块中的Objective-C对象时,它将被保留。 This is true even if you simply reference an instance variable of the object. 即使您只是引用对象的实例变量也是如此。 Object variables marked with the __block storage type modifier, however, are not retained. 但是,不保留使用__block存储类型修饰符标记的对象变量。
If you use a block within the implementation of a method, the rules for memory management of object instance variables are more subtle: 如果在方法的实现中使用块,则对象实例变量的内存管理规则更加微妙:
If you access an instance variable by reference, self is retained; 如果通过引用访问实例变量,则保留self;
If you access an instance variable by value, the variable is retained. 如果按值访问实例变量,则保留变量。
you reference self
in block, so self
is retained. 你在块中引用self
,所以保留self
。
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