Unbuffered Channels

In this lesson, explore unbuffered channels through one small Go program, and connect its output to the language rules behind it.

make(chan T) creates an unbuffered channel. A send completes only when a receiver can take the value; a receive waits until a sender provides one.

This rendezvous is often used to hand off work exactly when another goroutine is ready.

Follow this diagram before executing the example. Check where a value or decision changes what runs next.

This example is a complete program. Save it as main.go or paste it into the Go Playground.

Go code

package main

import "fmt"

func main() {
	handoff := make(chan int)
	go func() { handoff <- 7 }()
	n := <-handoff
	fmt.Println("Received:", n)
}

Output

Received: 7

Send and receive synchronize at the handoff. The receiver obtains 7 and prints it.

• Sending to an unbuffered channel with no concurrent receiver can deadlock.
• Unbuffered does not mean faster; it defines synchronization behavior.

Add a second handoff of 8 and explain when the sender can proceed.

Tip: Edit the example above, predict the output, and run the modified code to test your reasoning.

You have practiced Unbuffered Channels in a small, self-contained program. The important habit is to predict what runs, inspect the actual output and distinguish the language rule from the particular example.

Before continuing, make sure you can explain the program to someone who has not seen it, including the line that changes its result.