What locking or agreement mechanism is used inside a channel to ensure synchronization and data transfer?

In Go, channels provide synchronization and data transfer between goroutines using an built-in blocking mechanism. When a goroutine sends a value into a channel, it blocks until another goroutine reads that value from the channel. Similarly, if a goroutine tries to read from an empty channel, it blocks until data becomes available.

Thus, a channel acts as a synchronization object, ensuring safe data exchange without the need to explicitly use mutexes or other synchronization primitives.

Example:

ch := make(chan int)

// Sending in a goroutine
go func() {
    ch <- 42 // blocks until someone reads
}()

// Reading
value := <-ch // blocks until a value appears
fmt.Println(value)

This guarantees that data is transmitted and received synchronously.