When to dispatch_release()?

I'm fairly new to GCD and was trying to find an answer to this. Assuming I have the following code:

dis开发者_运维技巧patch_queue_t queue = dispatch_queue_create("queue", NULL);
dispatch_async(queue, ^{
    // do some stuff
});

Where in the code should I release the queue? Inside or outside the block?

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Outside the block. I'm fairly certain you don't have to wait for the async block to finish as GCD will retain the queue.