objective c simple singleton

SingletonManager.h

//  Created by Dennis White 
//  Copyright (c) 2014 dniswhite. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface SingletonManager : NSObject

+(id) sharedSingletonManager;

@end

SingletonManager.m

//  Created by Dennis White 
//  Copyright (c) 2014 dniswhite. All rights reserved.
//

#import "SingletonManager.h"

@implementation SingletonManager

+(id) sharedSingletonManager
{
    static SingletonManager * singletonManager = nil;
    static dispatch_once_t runOnce;
    
    dispatch_once(&runOnce, ^{
        singletonManager = [[self alloc] init];
    });
    
    return self;
}

-(id) init
{
    if (self = [super init]) {
        // init stuff here
    }
    
    return self;
}

@end