Buffered and unbuffered channels in Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an unbuffered channel in Go?

An unbuffered channel in Go is a channel with no capacity to hold data. It requires both sender and receiver to be ready at the same time for communication to happen, ensuring synchronization.

beginner

What is a buffered channel in Go?

A buffered channel in Go has a capacity to hold a fixed number of values. Senders can send data without waiting for a receiver until the buffer is full, allowing asynchronous communication up to the buffer size.

beginner

How do you create a buffered channel in Go?

You create a buffered channel using the make function with a capacity argument, like: ch := make(chan int, 3). This channel can hold 3 integers before blocking the sender.

intermediate

What happens when you send to a full buffered channel?

When you send to a buffered channel that is full, the sending goroutine blocks until some data is received from the channel, freeing space in the buffer.

intermediate

Why use buffered channels instead of unbuffered channels?

Buffered channels allow some decoupling between sender and receiver, letting the sender continue without waiting immediately. This can improve performance and avoid deadlocks in some cases.

What does an unbuffered channel guarantee in Go?

A Sender and receiver synchronize on each send and receive

B Sender can send multiple values without blocking

C Channel can hold multiple values in a queue

D Sender never blocks

Unbuffered channels require sender and receiver to be ready at the same time, ensuring synchronization.

How do you declare a buffered channel with capacity 5 in Go?

A ch := make(chan int)

B ch := chan int{5}

C var ch chan int = 5

D ch := make(chan int, 5)

Use make with a second argument for capacity: make(chan int, 5).

What happens if you send to a buffered channel that is not full?

A Send blocks until buffer is empty

B Send proceeds immediately without blocking

C Send blocks until receiver is ready

D Send causes a runtime error

If the buffer is not full, send does not block and proceeds immediately.

Which of these is true about buffered channels?

A They always block the sender

B They never block the receiver

C They can hold multiple values up to their capacity

D They are slower than unbuffered channels

Buffered channels hold multiple values up to their capacity before blocking the sender.

Why might you choose an unbuffered channel?

A To ensure sender and receiver synchronize on each message

B To store many messages in a queue

C To avoid blocking the sender

D To allow asynchronous communication

Unbuffered channels ensure synchronization between sender and receiver on each message.

Explain the difference between buffered and unbuffered channels in Go.

Think about whether the sender waits or not.

Describe a situation where using a buffered channel is better than an unbuffered channel.

Consider when you want to let sender continue without waiting.