> > 2. What does “concurrent and blocking” mean for a data structure?
I think this means they’re asking about a form of concurrent programming where a caller will stop executing (block) while the data structure is accessed by a concurrent path. Non-blocking means the caller can continue without the access completing. Concurrent means multiple code paths (either interwoven on one processor core or happening parallel on multiple cores) can read or write a shared data structure at the same time without data corruption. A key point to this explanation is that the data is in one computer memory that is shared between the code paths, but concurrency may also apply in different ways to programs designed for networks of computers (distributed computing) or other kinds of computer/OS architectures. The approach I know for “concurrent and blocking” is the mutex (https://golang.org/pkg/sync/#RWMutex). This approach is prone to deadlocks in some cases. There’s formal definitions in the study of concurrency that I avoided, the concept has been written about since the 1960s. See https://en.wikipedia.org/wiki/Mutual_exclusion for a Wikipedia starting point. 3. What does accessing one var from concurrent goroutines look like? Having a mutex is one way, either as a separate var or as part of the struct type, where a data interaction locks the mutex before accessing the data structure and unlocks it when done. With the Go sync.RWMutex any number of goroutines can read from a data structure concurrently, but if a write is happening then RLock will wait until the write completes (Unlock) before continuing (and Lock will wait for all RUnlock and Unlock to happen before continuing). Another is to use channels. These block while waiting to be read, or they can be buffered, so they could be part of a blocking or non-blocking concurrent data structure. I’ll probably explore this approach in the future since it doesn’t require a standard library dependency like the mutex does. Matt On Monday, April 9, 2018 at 12:03:10 PM UTC-5, Robert Solomon wrote: > > I would like to know the answers to 2 and 3 > > I'm a relatively new gopher > > On Mon, Apr 9, 2018, 12:59 PM Robert Solomon <drro...@gmail.com > <javascript:>> wrote: > >> I would like to know the answers to 2 and 3 >> >> I'm a relatively new gopher >> >>> -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
