Question

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?

Answer 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.