What are goroutines in Go?

Question

Accepted Answer

**Goroutines** — lightweight threads managed by Go runtime.

**Key points:**
- Cheap (start with 2KB stack).
- Managed by Go scheduler.
- Multiplexed onto OS threads.
- Can run millions concurrently.

```go
// Start goroutine
go func() {
    fmt.Println("Hello from goroutine")
}()

// Wait for goroutine
var wg sync.WaitGroup
wg.Add(1)
go func() {
    defer wg.Done()
    fmt.Println("Working...")
}()
wg.Wait()
```

**Comparison with threads:**
- Goroutine — 2KB initial stack.
- OS thread — 1-8MB stack.
- Goroutine — managed by Go.
- OS thread — managed by OS.

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