Are Objective-C blocks autoreleased?

问题:

If I declare a block like this ^{ DoSomething; } and put it in an instance variable, do I need to Block_copy() if I'm going to keep it around?

回答1:

Yes, you need to copy. Not because they are autoreleased, but because they start on the stack. Note that blocks also behave like regular Objective-C objects, so that you can copy them using the regular copy message:

void storeBlockForLater: (dispatch_block_t) block
{
    [someArray addObject:[[block copy] autorelease]];
}

Or, if you have a block property:

@property(copy) dispatch_block_t block;

Retaining does not help here.