Jan is correct, and you should probably use a sync.WaitGroup to keep your main() alive.
But even if you do that, you have a bigger problem. You channel is unbuffered. That means that `d <- a` will block until someone reads from d. Since `factorial` is the only goroutine that uses d, that line will block forever. (Of course, in your code, main() will exit after 3 seconds, so forever is short.) You can 'fix' the code by changing to a buffered channel, like: `d := make(chan int, 1)`. Then your code works, since the send will no longer block. Although it is pretty pointless to read from a channel in the same goroutine that writes to it. A more common use would be for the goroutine to send the result back to main, like this: https://play.golang.org/p/yJHJWhYif5h Note that, in this case, the channel read keeps main() from exiting before factorial() is finished. On Thursday, August 19, 2021 at 10:43:32 AM UTC-4 muhorto...@gmail.com wrote: > I just started practicing with channels, after writing to the channel, > nothing is output from there > func main() { > d := make(chan int) > go factorial(5, d) > time.Sleep(3 * time.Second) > } > > func factorial(n int, d chan int) { > fmt.Println("function starting...") > time.Sleep(3 * time.Second) > var a int = 1 > for ; n > 0; n-- { > a *= n > } > d <- a // //nothing works after that > fmt.Println(<-d) > fmt.Println(a) > } > > -------------------------------------------------------------------------------------------------------------------------------------------- > Another question I want to make a recursive function with a factorial, > pass it to goroutine in main. But I do not know if it is possible to > somehow combine *return* and a channel in the declaration of arguments. > > --------------------------------------------------------------------------------------------------------------------------------------------- > if I first pass in something to the channel from main, > a lock occurs.Why? So it's not possible at all? > -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/e81505fe-3415-4eb0-acf0-4b208e42fa13n%40googlegroups.com.
