var wl RWMutex
	var rl Locker
	wlocked := make(chan bool, 1)
	rlocked := make(chan bool, 1)
	rl = wl.RLocker()
	n := 10
	go func() {
		for i := 0; i < n; i++ {
			rl.Lock()
			rl.Lock()
			rlocked <- true
			wl.Lock()
			wlocked <- true
		}
	}()
	for i := 0; i < n; i++ {
		<-rlocked
		rl.Unlock()
		select {
		case <-wlocked:
			t.Fatal("RLocker() didn't read-lock it")

	wl := NewLRWMutex()
	var rl sync.Locker
	wlocked := make(chan bool, 1)
	rlocked := make(chan bool, 1)
	rl = wl.DRLocker()
	n := 10
	go func() {
		for i := 0; i < n; i++ {
			rl.Lock()
			rl.Lock()
			rlocked <- true
			wl.Lock()
			wlocked <- true
		}
	}()
	for i := 0; i < n; i++ {
		<-rlocked
		rl.Unlock()
		select {
		case <-wlocked:
			t.Fatal("RLocker() didn't read-lock it")

// open file descriptor.
package lock

import (
	"errors"
	"os"
	"sync"
)

// ErrAlreadyLocked is returned if the underlying fd is already locked.
var ErrAlreadyLocked = errors.New("file already locked")

// RLockedFile represents a read locked file, implements a special
// closer which only closes the associated *os.File when the ref count.
// has reached zero, i.e when all the readers have given up their locks.

	return r < 0 && r+rwmutexMaxReaders > 0
}

// RLocker returns a [Locker] interface that implements
// the [RWMutex.Lock] and [RWMutex.Unlock] methods by calling rw.RLock and rw.RUnlock.
func (rw *RWMutex) RLocker() Locker {
	return (*rlocker)(rw)
}

type rlocker RWMutex

func (r *rlocker) Lock()   { (*RWMutex)(r).RLock() }

			for semasleep(ns) < 0 {
				asmcgocall(*cgo_yield, nil)
			}
		}
		gp.m.blocked = false
		return true
	}

	deadline = nanotime() + ns
	for {
		// Registered. Sleep.
		gp.m.blocked = true
		if *cgo_yield != nil && ns > 10e6 {
			ns = 10e6
		}
		if semasleep(ns) >= 0 {
			gp.m.blocked = false
			// Acquired semaphore, semawakeup unregistered us.
			// Done.
			return true
		}

	expected := true
	if locked != expected {
		t.Errorf("TestSimpleWriteLockAcquired(): \nexpected %#v\ngot      %#v", expected, locked)
	}
}

func TestSimpleWriteLockTimedOut(t *testing.T) {
	locked := testSimpleWriteLock(t, testDrwMutexAcquireTimeout)

	expected := false
	if locked != expected {
		t.Errorf("TestSimpleWriteLockTimedOut(): \nexpected %#v\ngot      %#v", expected, locked)
	}
}

				unlocked = true
			}
		}
	}

	return unlocked
}

// ForceUnlock will forcefully clear a write or read lock.
func (lm *LRWMutex) ForceUnlock() {
	lm.mu.Lock()
	defer lm.mu.Unlock()

	lm.ref = 0
	lm.isWriteLock = false
}

// DRLocker returns a sync.Locker interface that implements
// the Lock and Unlock methods by calling drw.RLock and drw.RUnlock.

		casgstatus(gnext, _Gwaiting, _Grunnable)
		casgstatus(gnext, _Grunnable, _Grunning)
	}

	// Donate locked state.
	if locked {
		mp.lockedg.set(gnext)
		gnext.lockedm.set(mp)
	}

	// Release the trace locker. We've completed all the necessary transitions..
	if trace.ok() {
		traceRelease(trace)
	}

	// Switch to gnext. Does not return.
	gogo(&gnext.sched)

    // after some period of time the runner thread should become blocked on the task because it is
    // waiting for the slow interrupting thread to complete Thread.interrupt
    awaitBlockedOnInstanceOf(runner, InterruptibleTask.Blocker.class);

    Blocker blocker = (Blocker) LockSupport.getBlocker(runner);
    Thread owner = blocker.getOwner();
    assertThat(owner).isSameInstanceAs(interrupter);

    // after some period of time the runner thread should become blocked on the task because it is
    // waiting for the slow interrupting thread to complete Thread.interrupt
    awaitBlockedOnInstanceOf(runner, InterruptibleTask.Blocker.class);

    Blocker blocker = (Blocker) LockSupport.getBlocker(runner);
    Thread owner = blocker.getOwner();
    assertThat(owner).isSameInstanceAs(interrupter);