Reading values from a closed channel only returns zero values

closing_channels_sends_zero_vals.go

package main

import (
        "log"
)

func main() {
        // Also works with other channel types, like: chan string, chan int etc.
        // NOTE: The zero value for "bool" types is == false
        ch := make(chan bool)

        go func() {
                // Send out a bunch of non-zero (true) values to the channel.
                log.Println("goroutine start")
                for i := 10; i > 0; i-- {
                        ch <- true
                }

                // Trying to read values from a closed channel will only return zero (false)
                // values from it.
                close(ch)
                log.Println("goroutine stop")
        }()

        // Simulated "worker" that recieves values from the channel.
        log.Println("main start")
        for {
                val := <-ch
                log.Println("val =", val)

                // If we get a zero value (false) from the channel it
                // means it's been closed, time to quit.
                if val == false {
                        break
                }
        }
        log.Println("main stop")
}