关于Golang中for-loop与goroutine的问题详解

for i := 0; i < len(rf.peers); i++ {
  DPrintf("i = %d", i)

  if i == rf.me {
   DPrintf("skipping myself #%d", rf.me)
   continue
  }

  go func() {
   DPrintf("len of rf.peers = %d", len(rf.peers))
   DPrintf("server #%d sending request vote to server %d", rf.me, i)
   reply := &RequestVoteReply{}
   ok := rf.sendRequestVote(i, args, reply)
   if ok && reply.VoteGranted && reply.Term == rf.currentTerm {
    rf.voteCount++
    if rf.voteCount > len(rf.peers)/2 {
     rf.winElectionCh <- true
    }
   }
  }()
}

for val := range values {
 go val.MyMethod()
}

for val := range values {
 go func() {
  fmt.Println(val)
 }()
}

The val variable in the above loops is actually a single variable that takes on the value of each slice element. Because the closures are all only bound to that one variable, there is a very good chance that when you run this code you will see the last element printed for every iteration instead of each value in sequence, because the goroutines will probably not begin executing until after the loop.

for val := range values {
 go func(val interface{}) {
  fmt.Println(val)
 }(val)
}

for i := range valslice {
 val := valslice[i]
 go func() {
  fmt.Println(val)
 }()
}

server := i