How can I run code block in background periodically using GCD?

Question

How can I run code block in background periodically using GCD? I am trying to write a game engine with several subsystems, like rendering, physics, game logic and so on. Some ta

Answer 1

In Swift you can create timer using GCD:

func CreateTimerDispatchSource(interval: UInt64, leeway: UInt64, queue: dispatch_queue_t, block: dispatch_block_t) -> dispatch_source_t {
    let timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue)
    dispatch_source_set_timer(timer, dispatch_walltime(nil, 0), interval, leeway)
    dispatch_source_set_event_handler(timer, block)
    return timer;
}

var timer = CreateTimerDispatchSource(5*NSEC_PER_SEC, 0, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) { 
  // do some serious stuff
}

Start or resume timer:

dispatch_resume(timer)

Suspend timer:

dispatch_suspend(timer)