objective c - What GCD queue, main or not, am I running on? -

i trying write thread safe methods using:

... dispatch_queue_t main = dispatch_get_main_queue(); dispatch_sync(main,^{   [self dosomethingintheforeground]; }); ... 

but if on main thread not necessary, , can skip dispatch calls, know thread on. how can know this?

or, perhaps not make difference (in performance) doing it?

is ok comparison?

if (dispatch_get_main_queue() == dispatch_get_current_queue()){...} 

updated answer:

the apple docs have changed , "when called outside of context of submitted block, function returns main queue if call executed main thread. if call made other thread, function returns default concurrent queue." checking dispatch_get_main_queue() == dispatch_get_current_queue() should work.

original answer:

using dispatch_get_main_queue() == dispatch_get_current_queue() won't work. docs dispatch_get_current_queue "when called outside of context of submitted block, function returns default concurrent queue". default concurrent queue not main queue.

[nsthread ismainthread] should work want. note [nsthread ismainthread] can true for queues other main queue though, e.g., when calling dispatch_sync main thread.