检查是否有人从go频道阅读了

Question

How we can set something like listener on go channels that when someone has read something from the channel, that notify us?

Imagine we have a sequence number for channel entries and we wanna decrement it when someone had read a value from our channel somewhere out of our package.

Answer 1

Unbuffered channels hand off data synchronously, so you already know when the data is read. Buffered channels work similarly when the buffer is full, but otherwise they don't block the same, so this approach wouldn't tell you quite the same thing. Depending on what your needs really are, consider also using tools like sync.WaitGroup.

ch = make(chan Data)
  ⋮
for {
      ⋮
    // make data available
    ch <- data

    // now you know it was read
    sequenceNumber--
      ⋮
}