go/src/sync/rwmutex.go

type RWMutex …

const rwmutexMaxReaders …

// RLock locks rw for reading.
//
// It should not be used for recursive read locking; a blocked Lock
// call excludes new readers from acquiring the lock. See the
// documentation on the [RWMutex] type.
func (rw *RWMutex) RLock() { … }

// TryRLock tries to lock rw for reading and reports whether it succeeded.
//
// Note that while correct uses of TryRLock do exist, they are rare,
// and use of TryRLock is often a sign of a deeper problem
// in a particular use of mutexes.
func (rw *RWMutex) TryRLock() bool { … }

// RUnlock undoes a single [RWMutex.RLock] call;
// it does not affect other simultaneous readers.
// It is a run-time error if rw is not locked for reading
// on entry to RUnlock.
func (rw *RWMutex) RUnlock() { … }

func (rw *RWMutex) rUnlockSlow(r int32) { … }

// Lock locks rw for writing.
// If the lock is already locked for reading or writing,
// Lock blocks until the lock is available.
func (rw *RWMutex) Lock() { … }

// TryLock tries to lock rw for writing and reports whether it succeeded.
//
// Note that while correct uses of TryLock do exist, they are rare,
// and use of TryLock is often a sign of a deeper problem
// in a particular use of mutexes.
func (rw *RWMutex) TryLock() bool { … }

// Unlock unlocks rw for writing. It is a run-time error if rw is
// not locked for writing on entry to Unlock.
//
// As with Mutexes, a locked [RWMutex] is not associated with a particular
// goroutine. One goroutine may [RWMutex.RLock] ([RWMutex.Lock]) a RWMutex and then
// arrange for another goroutine to [RWMutex.RUnlock] ([RWMutex.Unlock]) it.
func (rw *RWMutex) Unlock() { … }

// syscall_hasWaitingReaders reports whether any goroutine is waiting
// to acquire a read lock on rw. This exists because syscall.ForkLock
// is an RWMutex, and we can't change that without breaking compatibility.
// We don't need or want RWMutex semantics for ForkLock, and we use
// this private API to avoid having to change the type of ForkLock.
// For more details see the syscall package.
//
//go:linkname syscall_hasWaitingReaders syscall.hasWaitingReaders
func syscall_hasWaitingReaders(rw *RWMutex) bool { … }

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

type rlocker …

func (r *rlocker) Lock()   { … }

func (r *rlocker) Unlock() { … }