golang中的happens begore
happens begore in golangvar c = make(chan int) // unbuffered channel, read happens before write
//var c = make(chan int, 1) // buffered channel, write happens before read
// close channel happens before read???
var a string
func f() {
a = "hello, world" // (1)
<-c // (2)
}
func main() {
go f()
c <- 0 // (3)
fmt.Println(a) // (4)
}
上例中，unbuffered channel能保证read操作发生在write之前，所以操作2发生在3之前，可以保证输出”hello, world”；
buffered channel的write发生在read之前，所以操作3在2之前，输出结果为空。