synchronisation

I need to have data synchronization in my code. Currently I am accessing a global value inside interrupt and also in a local function which may corrupt the data if interrupt call is frequent. I need to avoid this scenario. I am not using operating system in my code, so I cannot use a semaphore. Using a similar locking method as semaphore might solve my problem. Any help would be appreciated Interrupts work differently than threads or processes - if a thread waits for a semaphore, it is simply not scheduled until either the semaphore gets available or, if given, the wait timeout elapses. In the

Im quite new to iOS programming and now want to implement a periodic background synchronization to synchronize my server data with client data. What I want to achieve is comparable with Androids SyncAdapter where you can define a time interval (for example each 30 minutes) and the system will trigger the defined task automatically in the background. Until now I could not find such mechanism for Swift 3.0 so I need to ask if somone has experience or some hints for me how I can achieve this. What I want to do sounds quite simple: When the app starts for the first time the app should setup a sync

I've an expression of the form shown below :- while (count) { ... ... index = ((count == 20)? 0 : index++); ... ... } Now Ternary operators are sequence points in C but I believe that the sequence point ends at the test part. Is this understanding correct and as such will this statement lead to undefined behaviour ? Right. There's a sequence point after the evaluation of the condition, but the next sequence point is the semicolon terminating the statement. So whenever count != 20 , you have the undefined behaviour index = index++; since index is modified twice without intervening sequence