Go Learning notes-co-process

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Error:

Fatal Error:all Goroutines is asleep-deadlock!

Goroutine 1 [Chan receive]:

1, channel Buffer default is 0, directly write join error, errors as above

c: = make (chan int) without buffer channel

C <-1

Writes to a channel without a buffer, waits for the operation to be received, and ensures that the value is successfully received.
Will cause infinite waiting

With paired goroutine read, normal execution

c: = make (chan int)

Go func () {

C <-1

C <-2

C <-3

}()

<-c

Blocking order without buffers:

c: = make (chan int)

Go func () {

C <-1

Fmt. PRINTLN (4)

C <-2

Fmt. PRINTLN (5)

C <-3

Fmt. PRINTLN (6)

}()

Fmt. PRINTLN (7)

Fmt. Println (<-C)

Fmt. PRINTLN (8)

Fmt. Println (<-C)

Fmt. PRINTLN (9)

Fmt. Println (<-C)

Fmt. PRINTLN (10)

Output:

7

4

1

8

2

9

5

6

3

10

3, for range will always read the value within the channel, if no close will be error, error as above

c: = make (chan int, 1)

Go func () {

C <-1

C <-2

C <-3

Close (c)

}()

For I: = Range C {

Fmt. Println (i)

}

4, Select Case will be executed as soon as possible to return the case, can not return as soon as possible, will block waiting
The case expression will be executed