Menu
Given the following simple Go program
package main import ( "fmt" ) func total(ch chan int) { res := 0 for iter := range ch { res += iter } ch <- res } func main() { ch := make(chan int) go total(ch) ch <- 1 ch <- 2 ch <- 3 fmt.Println("Total is ", <-ch) } I am wondering if someone can enlighten me as to why I get
throw: all goroutines are asleep - deadlock! thank you
249
The WaitGroup type of sync package, is used to wait for the program to finish all goroutines launched from the main function. It uses a counter that specifies the number of goroutines, and Wait blocks the execution of the program until the WaitGroup counter is zero.
yourbasic.org/golang. A deadlock happens when a group of goroutines are waiting for each other and none of them is able to proceed.
A goroutine is a function that executes simultaneously with other goroutines in a program and are lightweight threads managed by Go. A goroutine takes about 2kB of stack space to initialize.
As you never close the ch channel, the range loop will never finish.
You can't send back the result on the same channel. A solution is to use a different one.
Your program could be adapted like this :
package main import ( "fmt" ) func total(in chan int, out chan int) { res := 0 for iter := range in { res += iter } out <- res // sends back the result } func main() { ch := make(chan int) rch := make(chan int) go total(ch, rch) ch <- 1 ch <- 2 ch <- 3 close (ch) // this will end the loop in the total function result := <- rch // waits for total to give the result fmt.Println("Total is ", result) } If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
