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NSRecursiveLock Class Reference

Overview

NSRecursiveLock defines a lock that may be acquired multiple times by the same thread without causing a deadlock, a situation where a thread is permanently blocked waiting for itself to relinquish a lock. While the locking thread has one or more locks, all other threads are prevented from accessing the code protected by the lock.

Adopted Protocols

• – lock

• – unlock

Tasks

Acquiring a Lock

• – lockBeforeDate:
• – tryLock

Naming the Lock

• – setName:
• – name

Instance Methods

lockBeforeDate:

Attempts to acquire a lock before a given date.

- (BOOL)lockBeforeDate:(NSDate *)limit

Parameters

limit

The time before which the lock should be acquired.

Return Value

YES if the lock is acquired before limit, otherwise NO.

Discussion

The thread is blocked until the receiver acquires the lock or limit is reached.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

NSLock.h

name

Returns the name associated with the receiver.

- (NSString *)name

Return Value

The name of the receiver.

Availability

• Available in Mac OS X v10.5 and later.

See Also

• – setName:

Declared In

NSLock.h

setName:

Assigns a name to the receiver

- (void)setName:(NSString *)newName

Parameters

newName

The new name for the receiver. This method makes a copy of the specified string.

Discussion

You can use a name string to identify a lock within your code. Cocoa also uses this name as part of any error descriptions involving the receiver.

Availability

• Available in Mac OS X v10.5 and later.

See Also

• – name

Declared In

NSLock.h

tryLock

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

- (BOOL)tryLock

Return Value

YES if successful, otherwise NO.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

NSLock.h

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