I have some code:
...
func Run(tasks []Task, n, m int) error {
...
for i := 0; i < n; i++ {
go func() {
defer wg.Done()
for t := range taskCh {
if atomic.LoadInt32(&errCount) >= int32(m) {
return
}
if err := t(); err != nil {
atomic.AddInt32(&errCount, 1)
}
}
}()
}
for _, t := range tasks {
taskCh <- t
}
close(taskCh)
wg.Wait()
if atomic.LoadInt32(&errCount) >= int32(m) {
err = ErrErrorsLimitExceeded
}
...
}
and its work fine, but why its does not work when I writing operating close() wg.Wait and if... on the defer?
...
defer func() {
close(taskCh)
wg.Wait()
if atomic.LoadInt32(&errCount) >= int32(m) {
err = ErrErrorsLimitExceeded
}
}()
for i := 0; i < n; i++ {
...
when variable errCount = 0
It is golang limitation that you cannot change returned variables from defer functions. The correct way to do this is (pay attention to (err error) named return value):
package main
import "fmt"
func someFunction() (err error) {
defer func() {
err = fmt.Errorf("Some error")
}()
err = fmt.Errorf("Some other error")
return
}
func main() {
fmt.Println(someFunction())
}