Go Language Goroutines

Internal

• Concurrency in Go

Overview

A goroutine is a Go thread. Many goroutines execute within a single O/S thread, the main thread?. From the O/S point of view, only one thread is scheduled. The goroutine schedule is done by the Go runtime scheduler. The Go runtime scheduler uses a logical processor. The goroutines scheduled on a logical processor are executing concurrently, not |in parallel. However, it is possible to have more than one logical processor, each logical processors can be mapped onto an O/S thread, which may be scheduled to work on different cores. In this case, things may become parallel.

A goroutine is always created automatically, to run the main() function.

Creation and Invocation

To explicitly create a goroutine and schedule it, use the go keyword, by providing a function invocation.

func somefunc(i int) {
  ...
}

...

go somefunc(10)

Any function invocation can be used: go fmt.Printf("something").

Note that this syntax only schedules a goroutine. It is not determined when it will be actually executed.

what happens with the result of the function?

Exiting

A goroutine exits when the code is complete.

When the main goroutine is complete, all other goroutines are forced to exit. It is said that those goroutines exit early.