NSDistributedLock

This class provides an interface to an object that can be used by multiple applications to control access to a shared resource (such as a file). This class works by creating an entry in the filesystem at a path known to each application that is interested in acquiring a lock to access the shared resource.

A distributed lock object is initialized with a filesystem entry using the method initWithPath:. To acquire a lock, thus making it safe to access a resource, we use the method tryLock. This method returns a BOOL indicating whether or not it was successful in attempting to acquire a lock. To relinquish a previously acquired lock, use the method unlock.

@interface NSDistributedLock : NSObject

 // Initializers

   - (id)initWithPath:(NSString *)path;

 // Class Methods

   + (NSDistributedLock *)lockWithPath:(NSString *)path;

 // Instance Methods

   - (void)breakLock;

   - (NSDate *)lockDate;

   - (BOOL)tryLock;

   - (void)unlock;