In the given code, I have closed a channel in generateOne and then used the same channel in the next function to write on. This will panic with a message send on closed channel. Can anyone tell me how I can make sure if the channel is closed or not before sending any data?

Note: This is a Unidirectional channel.

package main

import "time"

func generateOne(a chan<- int) {
    for i := 0; i < 10; i++ {
        a <- i
    }
    close(a)
}

func generateTwo(a chan<- int) {
    for {
        a <- 10
    }
}

func consume(a <-chan int) {
    for {
        data, ok := <-a
        if ok == false {
            break
        }
        println(data)
    }
}

func main() {
    a := make(chan int)
    go generateOne(a)
    go generateTwo(a)
    go consume(a)
    time.Sleep(1 * time.Second)
}

Hello there,

I have a channel chan error with a reading and writing goroutines using it. It is known in advance the writing goroutine writes to it only once then closes it. Should the reader goroutine read the error from the channel and then read again the channel closing to drain it? Or is there no need (resource usage wise) to drain a closed channel?

Code example (as requested):

ch := make(chan int)
go func(writeCh chan<- int) {
  writeCh <- 1
  close(writeCh)
}(ch)

go func(readCh <-chan int) {
  _ = <-readCh // read the 1
  _ = <-readCh // should I drain the channel??
}(ch)

Thanks!