On Sat, Sep 4, 2021 at 5:55 PM Michael Dwyer <michael.k.dw...@gmail.com> wrote:
> I encountered a deadlock when reading from a buffered channel. > The deadlock occurs when an attempt is made to read from the channel > twice, without an intermediate write to the channel. > That is not a deadlock. Reading from a buffered channel blocks when the channel is empty. From https://golang.org/ref/spec#Channel_types: Otherwise, the channel is buffered and communication succeeds without blocking if the buffer is not full (sends) or not empty (receives). A nil channel is never ready for communication. You can use the "select" operator ( https://golang.org/ref/spec#Select_statements) to detect if the channel is empty. > The problematic code is as follows: > > func main() { > myInt := 432 > > readerChan := make(chan int, 3) > > for forI := 0; forI <= 10000; forI++ { > readerChan <- myInt > fmt.Printf("%d:", <- readerChan) > fmt.Printf("%d:", <- readerChan) > } > > close(readerChan) > } > > The first read from variable readerChan succeeds. > The second read from variable readerChan results in a deadlock. > > I have two links to playground. > The first link is the problematic code. > The second link is for similar code that has an intervening write to the > channel. > > I understand that a buffered channel allows a queue of results to be > stored from other Go routines writing to the channel. > But, the code is attempting multiple read operations. > > Looking for a technical explanation to help me better understand this > particular case. > Thanks in advance ... > > > The problematic playground link : https://play.golang.org/p/veo7phAZzMv > The working playground link : https://play.golang.org/p/qvYZNN9keqN > > > THANX(MKD). > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/44057a7a-b0aa-4ea1-9fb3-39836cd5713dn%40googlegroups.com > <https://groups.google.com/d/msgid/golang-nuts/44057a7a-b0aa-4ea1-9fb3-39836cd5713dn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- Kurtis Rader Caretaker of the exceptional canines Junior and Hank -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CABx2%3DD_H-na_90DyY_PCzakLjBuz3ehN1hoVOj1Y%2BTc26tPN_A%40mail.gmail.com.
