Question

I was going over the RunLoop iOS documentation and it discusses the idea illustrated here:

_{(source: apple.com)}

in the RunLoopSource it provides the following interface for client threads (ie the Main thread in the above illustration) to fill the audio buffer with commands and data, and to subsequently fire all commands available in the said buffer:

// Client interface for registering commands to process
- (void)addCommand:(NSInteger)command withData:(id)data
- (void)fireAllCommandsOnRunLoop:(CFRunLoopRef)runloop 

In the add command method we’re simply adding commands to an NSMutableArray data structure.

My question is how can we encapsulate those commands in variables such that they are methods.. the data variable in the addCommand method is of type id.. can we put a block in there for example? Are there any best practices here/sample code etc? thanks.

Answer 1

This technique pre-dates blocks. The beauty about using blocks with concurrency is that you can throw as much work as you want at the system, and given its total device scope can schedule that work on multiple cores and threads as it sees fit. You can also use a concurrent NSOperation and have it implement a fifo to accept work and process it, but in this case there will only be the secondary thread, and it will again be scheduled run time as the system sees fit to giving it, so no advantage over blocks.