Multithreaded GCD full version

Dispatch_: How threads Perform tasks in the queue. (synchronous, asynchronous, delay, once, multiple),,

Queue: A collection of some serial or parallel tasks,

System queue: Primary queue, (running in the main thread, serial)

Global queue, (4, parallel)

1.1, GCD four priority of global queue
1.2, several types of gcd used in this article
1.3, Dispatch_async/dispatch_async_f
1.4, Dispatch_sync/dispatch_sync_f

http://blog.csdn.net/Hello_Hwc/article/details/41073287

2.1, Dispatch_after
2.2, Dispatch_apply
2.3, Dispatch_once

http://blog.csdn.net/hello_hwc/article/details/41204027

3.Dispatch_group

http://blog.csdn.net/hello_hwc/article/details/41409135

4.dispatch_semaphore (semaphore)

http://blog.csdn.net/hello_hwc/article/details/42463645

Multithreaded GCD full version