# General Problems

# What is a goroutine? how to stop it?

a goroutine is a go-defined, user-space, light-weight thread(different from pthread from linux).

we have to use signal to stop a goroutine

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func main() {
  stop := make(chan bool)
  go func() {
    for {
      select {
        case <-stop:
          return
        default:
          fmt.Println("working...")
          time.Sleep(5000)
      }
    }
  }()

  ...
  stop <- true
}

# What should be taken care of when we use channel

• sending/receiving data to a nil-channel, both will be blocked forever
• sending data to a closed channel will panic
• receiving data from a closed channel, if the buffer is empty, would return a zero-value

• buffered channel is async
• no-buffer channel is sync

# the difference between new and make

• func new(Type) *Type
  • use new to assign memory
  • new requires a type, not a value
  • the return value is the pointer to the new created memory block
• func make(Type, size IntegerType) Type
  • make is used to initialize slice, map, chan, and return reference