RosettaCodeData/Task/Singleton/Objective-C/singleton-3.m

+ (SomeSingleton *) sharedInstance
{
   static SomeSingleton *sharedInstance = nil;
   @synchronized(self) {
      if (!sharedInstance) {
         sharedInstance = [[SomeSingleton alloc] init];
      }
   }
   return sharedInstance;
}