This question already has an answer here:
- Go channels and deadlock 2 answers
I am trying to have two separate consumer go routines, that would filter out even and odd numbers from the input channel. This is just a toy example in order to see if it is possible to have consumers do something with the message read from the input channel if it matches certain condition, otherwise put back onto the input channel.
My current code is as follows:
package main
func filterOdd(ch chan int, out chan int) {
val := <- ch
if val % 2 == 0 {
ch <- val
} else {
out <- val
}
}
func filterEven(ch chan int, out chan int) {
val := <- ch
if val % 2 != 0 {
ch <- val
} else {
out <- val
}
}
func main() {
even := make(chan int)
odd := make(chan int)
input := make(chan int)
go filterOdd(input, odd)
go filterEven(input, even)
for i:=1; i <= 10; i++ {
input <- i
}
println("Even...")
for i := range even {
println(i)
}
println("Odd...")
for i := range odd {
println(i)
}
}
However, this produces the following output:
fatal error: all goroutines are asleep - deadlock!
goroutine 1 [chan send]:
main.main()
/tmp/sandbox594577124/main.go:27 +0x140
goroutine 4 [chan send]:
main.filterOdd(0x10336100, 0x103360c0)
/tmp/sandbox594577124/main.go:8 +0xc0
created by main.main
/tmp/sandbox594577124/main.go:24 +0xc0
Link to the Go Playground: https://play.golang.org/p/9RIvFsGKI-
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