How should data be correctly read from a non-buffered channel?

In Go, to read data from a channel without buffering, you should use non-blocking read or read with data availability check. Channels can be buffered or unbuffered by default, but to read without buffering, unbuffered channels are usually used along with the <- operator.

Example of reading from an unbuffered channel:

ch := make(chan int) // unbuffered channel

// Sending in a separate goroutine
go func() {
    ch <- 42
}()

// Reading (will wait until data appears)
value := <-ch
fmt.Println(value) // 42

To avoid blocking during read, you can use a select statement with a default case:

select {
case val := <-ch:
    fmt.Println("Received", val)
default:
    fmt.Println("No data")
}