> For the complete documentation index, see [llms.txt](https://openai.gitbook.io/code-cheatsheets/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://openai.gitbook.io/code-cheatsheets/all/go/goroutine.md).

# GoRoutines

A lightweight thread managed by go, same address space, must sync access to shared mem

```go
go f(x, y, z) //starts goroutine running f(x,y,z)
```

## Channels

Channels are a typed conduit through which you can send and receive values with the channel operator, `<-`.

```
ch <- v    // Send v to channel ch.
v := <-ch  // Receive from ch, and
           // assign value to v.
```

(The data flows in the direction of the arrow.)

Like maps and slices, channels must be created before use:

```
ch := make(chan int)
```

By default, sends and receives block until the other side is ready.

### Sum Example

```go
package main

import "fmt"

func sum(s []int, c chan int) {
    sum := 0
    for _, v := range s {
        sum += v
    }
    c <- sum // send sum to c
}

func main() {
    s := []int{7, 2, 8, -9, 4, 0}

    c := make(chan int)
    go sum(s[:len(s)/2], c)
    go sum(s[len(s)/2:], c)
    x, y := <-c, <-c // receive from c

    fmt.Println(x, y, x+y)
}
```