What is the difference between goroutine and thread?

Question

Accepted Answer

**Goroutine** — lightweight. **Thread** — OS.

```go
go func() {}()
```

**Stack:**
- Goroutine: 2KB.
- Thread: MB.

**When to use goroutines:**
- I/O-bound concurrency.
- Background tasks.

**When to use threads:**
- Cgo interop.
- Thread-local storage.

**Common mistakes:**
- Not synchronizing completion.
- Closure variable capture.
- Assuming goroutines are parallel.
- Creating too many without backpressure.
- Using `runtime.LockOSThread()` unnecessarily.

Go: What is the difference between goroutine and thread?