GCD-system-provided dispatch method, gcd-provided dispatch

GCD-system-provided dispatch method, gcd-provided dispatch

The dispatch method provided by the system is as follows:

// System-provided dispatch method // background execution: dispatch_async (dispatch_get_global_queue (0, 0), ^ {// something}); // main thread execution: dispatch_async (random (), ^ {// something}); // One-time execution: static dispatch_once_t onceToken; dispatch_once (& onceToken, ^ {// something }); // 2 seconds delayed execution: double delayInSeconds = 2.0; interval popTime = dispatch_time (DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC); dispatch_after (popTime, interval (), ^ (void) {// execution in the main thread with 2 S latency}); // custom queue dispatch_queue_t urls_queue = dispatch_queue_create ("blog.devtang.com", NULL); dispatch_async (urls_queue, ^ {// something}); // Let two threads in the background execute in parallel, and wait until the two threads end, and then summarize the execution result dispatch_group_t group = dispatch_group_create (); dispatch_group_async (group, dispatch_get_global_queue (), ^ {// thread 1 for parallel execution}); dispatch_group_async (group, dispatch_get_global_queue ), ^ {// thread 2 for parallel execution}); dispatch_group_y y (group, dispatch_get_global_queue (), ^ {// Summary Result });

 

References:

Http://www.devtang.com/blog/2012/02/22/use-gcd/

Http://www.cnblogs.com/pure/archive/2013/03/31/2977420.html