Nonblocking Receive

A default case lets select continue when no channel receive is ready.

nonblocking_receive.go

package main

import "fmt"

func main() {
	var preload = 
	inbox := make(chan string, 1)

	if preload {
		inbox <- "message"
	}

	status := ""
	select {
	case value := <-inbox:
		status = "received " + value
	default:
		status = "nothing ready"
	}

	fmt.Println("preload=", preload)
	fmt.Println("status=", status)
	fmt.Println("remaining=", len(inbox))
}

package main

import "fmt"

func main() {
	var preload = 
	inbox := make(chan string, 1)

	if preload {
		inbox <- "message"
	}

	status := ""
	select {
	case value := <-inbox:
		status = "received " + value
	default:
		status = "nothing ready"
	}

	fmt.Println("preload=", preload)
	fmt.Println("status=", status)
	fmt.Println("remaining=", len(inbox))
}

default case A `default` case prevents a `select` from blocking when no channel operation can proceed.