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
		}

		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)

// relation at all.
//
// [the Go memory model]: https://go.dev/ref/mem
type Mutex struct {
	state int32
	sema  uint32
}

// A Locker represents an object that can be locked and unlocked.
type Locker interface {
	Lock()
	Unlock()
}

const (
	mutexLocked = 1 << iota // mutex is locked
	mutexWoken
	mutexStarving
	mutexWaiterShift = iota

	// Mutex fairness.
	//

	default:
		atomic.StoreInt64(&m.LastPing, time.Now().Unix())
		return pongMsg{}
	}
}

// disconnect will disconnect the mux.
// m.recvMu must be locked when calling this function.
func (m *muxServer) disconnect(msg string, locked bool) {
	if debugPrint {
		fmt.Println("Mux", m.ID, "disconnecting. Reason:", msg)
	}
	if msg != "" {

	// while sleeping.
	acquireLockRankAndM(rw.readRank)
	lockWithRankMayAcquire(&rw.rLock, getLockRank(&rw.rLock))

	if rw.readerCount.Add(1) < 0 {
		// A writer is pending. Park on the reader queue.
		systemstack(func() {
			lock(&rw.rLock)
			if rw.readerPass > 0 {
				// Writer finished.
				rw.readerPass -= 1
				unlock(&rw.rLock)
			} else {
				// Queue this reader to be woken by
				// the writer.
				m := getg().m

		// Sleep for an arbitrary-but-moderate interval to poll libc interceptors.
		ns = 10e6
	}
	for atomic.Load(key32(&n.key)) == 0 {
		gp.m.blocked = true
		futexsleep(key32(&n.key), 0, ns)
		if *cgo_yield != nil {
			asmcgocall(*cgo_yield, nil)
		}
		gp.m.blocked = false
	}
}

// May run with m.p==nil if called from notetsleep, so write barriers
// are not allowed.
//
//go:nosplit

}

var (
	locked  atomic.Int32
	runGoid atomic.Uint64
	hooks   []Hook
	running bool

	// runtime sets these for us
	Gosched func()
	Goid    func() uint64
	Throw   func(string)
)

// Add adds a new exit hook.
func Add(h Hook) {
	for !locked.CompareAndSwap(0, 1) {
		Gosched()
	}
	hooks = append(hooks, h)
	locked.Store(0)
}

// Run runs the exit hooks.
//

			os.Exit(1)
		}
		// Exit with the thread locked, which should exit the
		// main thread.
		ready <- true
	}()
	<-ready
	time.Sleep(1 * time.Millisecond)
	// Check that this goroutine is still running on a different
	// thread.
	if mainTID != 0 && gettid() == mainTID {
		println("goroutine migrated to locked thread")
		os.Exit(1)
	}
	println("OK")
}

func LockOSThreadAlt() {

// blocked goroutines, LockOSThread, pipes, and GOMAXPROCS).

//go:build ignore

package main

import (
	"log"
	"net"
	"os"
	"runtime"
	"runtime/trace"
	"sync"
	"time"
)

func main() {
	var wg sync.WaitGroup
	done := make(chan bool)

	// Create a goroutine blocked before tracing.
	wg.Add(1)
	go func() {
		<-done
		wg.Done()