to define an interface called <code>Locker</code>:
</p>

<pre>
type Locker interface {
	Lock()
	Unlock()
}
</pre>

<p>
If <code>S1</code> and <code>S2</code> also implement
</p>

<pre>
func (p T) Lock() { … }
func (p T) Unlock() { … }
</pre>

<p>
they implement the <code>Locker</code> interface as well
as the <code>File</code> interface.

pkg syscall (freebsd-arm64), const RTF_REJECT = 8
pkg syscall (freebsd-arm64), const RTF_REJECT ideal-int
pkg syscall (freebsd-arm64), const RTF_RNH_LOCKED = 1073741824
pkg syscall (freebsd-arm64), const RTF_RNH_LOCKED ideal-int
pkg syscall (freebsd-arm64), const RTF_STATIC = 2048
pkg syscall (freebsd-arm64), const RTF_STATIC ideal-int
pkg syscall (freebsd-arm64), const RTF_STICKY = 268435456

to define an interface called <code>Locker</code>:
</p>

<pre>
type Locker interface {
	Lock()
	Unlock()
}
</pre>

<p>
If <code>S1</code> and <code>S2</code> also implement
</p>

<pre>
func (p T) Lock() { … }
func (p T) Unlock() { … }
</pre>

<p>
they implement the <code>Locker</code> interface as well
as the <code>File</code> interface.

		for {
			select {
			case <-stop:
				return
			case <-time.After(time.Millisecond * 100):
			}
		}
	}()
	defer close(stop)

	for i := 0; i < 1000; i++ {
		if !C.Ctid() {
			t.Fatalf("cgo has not locked OS thread")
		}
	}