问题
When I have a block in Objective-C that looks like this:
self.request = [[ASIHTTPRequest requestWithURL:...
[self.longPollRequest setCompletionBlock:^{
NSLog(@"%@", self.request.responseString);
}];
will it retain self or explicitly retain self.request?
回答1:
As the Block Programming Topics says:
In a reference-counted environment, by default when you reference an Objective-C object within a block, it is retained. This is true even if you simply reference an instance variable of the object. Object variables marked with the __block storage type modifier, however, are not retained.
If you use a block within the implementation of a method, the rules for memory management of object instance variables are more subtle:
If you access an instance variable by reference, self is retained;
If you access an instance variable by value, the variable is retained.
you reference self in block, so self is retained.
来源：https://stackoverflow.com/questions/6433790/is-self-retained-within-this-objective-c-block