In order to have full access Grand Central Dispatch (GCD) APIs, MacRuby has the module and some classes.

• Dispatch Module
• Dispatch::Queue Class
• Dispatch::Group Class
• Dispatch::Source Class
• Dispatch::Semaphore Class

Indicates a time that occurs immediately. This constant is defined in GCD API as DISPATCH_TIME_NOW.

gcdq = Dispatch::Queue.new('sample')
gcdq.after(Dispatch::TIME_NOW) { puts "Hello" }

sleep 0.5

Indicates a time that means infinity. This constant is defined in GCD API as DISPATCH_TIME_FOREVER.

gcdq = Dispatch::Queue.new('sample')
sema = Dispatch::Semaphore.new(0)
gcdq.async {
  puts "Hello, "
  sleep 1
  sema.signal
}

puts "Waiting..."

sema.wait(Dispatch::TIME_FOREVER)
puts "World"

Resume the invocation of suspended dispatch queue or dispatch event source objects on a dispatch object. This method is declared in GCD API as dispatch_resume.

• resume!

gcdq = Dispatch::Queue.new('sample')
gcdq.after(Dispatch::TIME_NOW) { 
  sleep 0.5
  puts "Hello"
}
gcdq.suspend!
gcdq.suspended?  #=> true
gcdq.resume!

sleep 1

Suspends the invocation of dispatch queue or dispatch event source objects on a dispatch object. This method is declared in GCD API as dispatch_suspend.

• suspend!

Returns whether the invocation is suspended.

• suspended? -> bool
  • [RETURN]
    • Returns a true if suspended, otherwise false.

Returns the object of dispatch_object_t type for passing into Cocoa APIs which need the object of dispatch_queue_t type and etc.

• dispatch_object -> object
  • [RETURN]
    • Returns a dispatch object

gcdq = Dispatch::Queue.new('doc')
output = AVCaptureVideoDataOutput.new
output.setSampleBufferDelegate(self, queue: gcdq.dispatch_object)