dispatch_after — schedule blocks for deferred execution

       Specifying DISPATCH_TIME_NOW as the when parameter is supported, but  is  not  as  efficient  as  calling
       dispatch_async().  The result of passing DISPATCH_TIME_FOREVER as the when parameter is undefined.

       The  dispatch_after()  function  submits  the  block to the given queue at the time specified by the when
       parameter.  The when parameter is a value created by dispatch_time() or dispatch_walltime().

       For a more detailed description about submitting blocks to queues, see dispatch_async(3).

       The dispatch_after() function is a wrapper around dispatch_after_f().

       dispatch_after — schedule blocks for deferred execution

dispatch(3), dispatch_async(3), dispatch_time(3)

Darwin                                             May 1, 2009                                 dispatch_after(3)

#include<dispatch/dispatch.h>voiddispatch_after(dispatch_time_twhen, dispatch_queue_tqueue, void(^block)(void));

       voiddispatch_after_f(dispatch_time_twhen, dispatch_queue_tqueue, void*context, void(*function)(void*));