Go Concurrency

ch := make(chan int, 2)
ch <- 1
ch <- 2
ch <- 3
// fatal error:
// all goroutines are asleep - deadlock

See: Buffered channels

ch <- 1
ch <- 2
ch <- 3
close(ch) // Closes a channel

// Iterate the channel until closed
for i := range ch {
  ···
}

// Closed if `ok == false`
v, ok := <- ch

See: Range and close

package main
import (
    "fmt"
    "sync"
    "time"
)
func w(id int, wg \*sync.WaitGroup) {
    defer wg.Done()
    fmt.Printf("%d starting\n", id)
    time.Sleep(time.Second)
    fmt.Printf("%d done\n", id)
}
func main() {
    var wg sync.WaitGroup
    for i := 1; i <= 5; i++ {
        wg.Add(1)
        go w(i, &wg)
    }
    wg.Wait()
}

See: WaitGroup

package main
import (
    "fmt"
    "time"
)
func f(from string) {
    for i := 0; i < 3; i++ {
        fmt.Println(from, ":", i)
    }
}
func main() {
    f("direct")
    go f("goroutine")
    go func(msg string) {
        fmt.Println(msg)
    }("going")
    time.Sleep(time.Second)
    fmt.Println("done")
}

See: Goroutines, Channels