Channel Operations: Send, Receive, Close, and Select

Problem Statement

Master all channel operations and their edge cases. This knowledge is essential for writing correct concurrent Go programs.

Channel Behavior Reference

Operation	Nil Channel	Closed Channel	Open Channel
ch <- v (send)	Blocks forever	PANIC	Blocks until received
<-ch (receive)	Blocks forever	Returns zero, false	Blocks until sent
close(ch)	PANIC	PANIC	Closes successfully

Key Interview Questions

Q1: What happens if you send to a closed channel?

Q2: What happens if you receive from a closed channel?

Q3: What happens if you send/receive on a nil channel?

Use case: Disable a select case dynamically by setting channel to nil.

Q4: How do you implement a non-blocking send?

Q5: Buffered vs Unbuffered channels

Q6: How do you drain a channel after closing?

Q7: Implement timeout with select

Q8: Can you close a receive-only channel?