select break
go中使用for select 结构，select的break只能跳出break，不能跳出for循环
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package main
import (
"fmt"
"time"
)
func main() {
ch := make(chan int)
ok := make(chan bool)
go func() {
ch <- 1
ch <- 2
ch <- 3
close(ch)
}()
go test(ch, ok)
<-ok
}
func test(ch chan int, ook chan bool) {
for {
select {
case resp, ok := <-ch:
if !ok {
break
}
fmt.Println(resp)
case <-time.After(time.Second):
fmt.Printf("1s now!")
break
}
}
}
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chan close
向关闭的chan读取数据，chan会返回相关的空数据，内置类型返回0值数据，自定义struct返回空指针
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package main
import (
"fmt"
"time"
)
type Obj struct {
val int
name string
}
func main() {
ch := make(chan int, 1)
ok := make(chan *Obj, 2)
go func() {
defer close(ok)
defer close(ch)
ok <- &Obj{val: 1, name: "ww"}
ch <- 1
}()
go test(ch, ok)
select {
case <-time.After(2 * time.Second):
fmt.Println("2s close main")
}
}
func test(ch chan int, ok chan *Obj) {
i := 0
for {
o := <-ok
fmt.Println(o)
r := <-ch
fmt.Println(r)
i++
if i >= 2 {
break
}
}
}
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go panic
协程panic，如果没有recover，则会crash整个程序
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package main
import (
"fmt"
"time"
)
func main() {
go func() {
panic("1")
}()
time.Sleep(time.Second)
fmt.Println("2")
}
|