That code is incorrect as well when using buffered channels. 

> On Dec 18, 2018, at 10:00 AM, Skip Tavakkolian <skip.tavakkol...@gmail.com> 
> wrote:
> 
> why not just  drop the select? i think the following is guaranteed because 
> putting things on rc has to succeed before putting true into dc:
> 
> package main
> 
> import (
>       "fmt"
> )
> 
> func do(i int, rc chan<- int, dc chan<- bool) {
>       rc <- i
>       dc <- true
> }
> 
> func main() {
>       worker := 10
>       rc := make(chan int, worker)
>       done := 0
>       dc := make(chan bool, worker)
>       for i := 0; i < worker; i++ {
>               go do(i, rc, dc)
>       }
>       for done < worker {
>               r := <-rc
>               fmt.Println(r)
>               <-dc
>               done++
>       }
> }
> 
> 
>> On Tue, Dec 18, 2018 at 5:35 AM Chris Burkert <burkert.ch...@gmail.com> 
>> wrote:
>> Dear all,
>> 
>> I have a couple of goroutines sending multiple results over a channel - a 
>> simple fan-in. They signal the completion on a done channel. Main selects on 
>> the results and done channel in parallel. As the select is random main 
>> sometimes misses to select the last result. What would be the idiomatic way 
>> to prevent this and completely drain the result channel?
>> 
>> Here is a minmal example which sometimes prints one 0 but should always 
>> print two of them:
>> 
>> package main
>> 
>> import (
>>         "fmt"
>> )
>> 
>> func do(rc chan<- int, dc chan<- bool) {
>>         rc <- 0
>>         dc <- true
>> }
>> 
>> func main() {
>>         worker := 2
>>         rc := make(chan int, worker)
>>         done := 0
>>         dc := make(chan bool, worker)
>>         for i := 0; i < worker; i++ {
>>                 go do(rc, dc)
>>         }
>>         for done < worker {
>>                 select {
>>                 case <-dc:
>>                         done++
>>                 case r := <-rc:
>>                         fmt.Println(r)
>>                 }
>>         }
>> }
>> 
>> many thanks
>> Chris
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