Mastering Go - Second Edition

Nil channels

In this subsection, you will learn about nil channels. These are a special kind of channel because they always block. They are illustrated in nilChannel.go, which will be presented in four code segments.

The first part of nilChannel.go is as follows:

package main 
 
import ( 
    "fmt" 
    "math/rand" 
    "time" 
) 

The second code portion of nilChannel.go is shown in the following Go code:

func add(c chan int) { 
    sum := 0 
    t := time.NewTimer(time.Second) 
 
    for { 
        select { 
        case input := <-c: 
            sum = sum + input 
        case <-t.C: 
            c = nil 
            fmt.Println(sum) 
        } 
    } 
} 

The add() function demonstrates how a nil channel is used. The <-t.C statement blocks the c channel of the t timer for the time that is specified in the time.NewTimer() call. Do not confuse channel ...