Golang Concurrency

gistfile1.go

// Concurrency in Go
// ----------------------------------------------------------------
// several processes running at the same time
// dealing with lots of things at once (connections, computations)
// long live Murphy's^H^H^H^H^H^H^HMoore's law!

// Three things: execution, syncing/messaging and control flow

// 1) GOROUTINES          
// ----------------------------------------------------------------                                               
// almost like threads but not really, closest ~ is shell's &
// multiplexed over OS threads as necessary
// "500k goroutines simultaneously" - jordan from batch[1]
func main() {
  go func() {
    time.Sleep(5)
    fmt.Println("hi")
  }()
}

// 2) CHANNELS
// ----------------------------------------------------------------
// where did my goroutine go?
// send and receive messages with the channel operator <-
c := make(chan int)
go sum(a[:len(a)/2], c) // sum first part of list
go sum(a[len(a)/2:], c) // sum second part of the list

// in sum function
c <- sum // send partial sum to channel c

x,y := <-c, <-c // receive from channel c
fmt.Println(x+y) // print total sum

// can also have buffered channels...
ch := make(chan int, 100)
// ...so when the buffer is full it blocks (throws an exception)

// 3) SELECT
// ----------------------------------------------------------------
// a control structure like if, switch and for
// are my channels ready yet?
// like a switch but...
// "based on ability to communicate rather than equal values" -rob pike
select {
// something to receive from channel c?
case v := <-c:
  // channel c is sending v
case <-quit:
  // got a quit message
default:
  // no channel is ready, do something else to avoid blocking
}

// Bonus: ERROR HANDLING
// ----------------------------------------------------------------
p, err := loadPage(title)
  if err != nil {
    p = &Page{Title: title}
  }

vad är detta?

liten presentation om concurrency i go bara :p

…

On Mon, Aug 6, 2012 at 3:07 PM, Ben Brittain < ***@***.*** > wrote: vad är detta? --- Reply to this email directly or view it on GitHub: https://gist.github.com/3259872