An object that coordinates the operation of multiple threads of execution within the same application.


class NSLock : NSObject


An NSLock object can be used to mediate access to an application’s global data or to protect a critical section of code, allowing it to run atomically.

You should not use this class to implement a recursive lock. Calling the lock method twice on the same thread will lock up your thread permanently. Use the NSRecursiveLock class to implement recursive locks instead.

Unlocking a lock that is not locked is considered a programmer error and should be fixed in your code. The NSLock class reports such errors by printing an error message to the console when they occur.


Acquiring a Lock

func lock(before: Date) -> Bool

Attempts to acquire a lock before a given time and returns a Boolean value indicating whether the attempt was successful.

func `try`() -> Bool

Attempts to acquire a lock and immediately returns a Boolean value that indicates whether the attempt was successful.

Naming the Lock

var name: String?

The name associated with the receiver.


Inherits From

See Also

Threads and Locking

class Thread

A thread of execution.

protocol NSLocking

The elementary methods adopted by classes that define lock objects.

class NSRecursiveLock

A lock that may be acquired multiple times by the same thread without causing a deadlock.

class NSDistributedLock

A lock that multiple applications on multiple hosts can use to restrict access to some shared resource, such as a file.

class NSConditionLock

A lock that can be associated with specific, user-defined conditions.

class NSCondition

A condition variable whose semantics follow those used for POSIX-style conditions.

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