Create singleton classes for Objective-C

MySingleton

MySingleton.h
---------------

#import <Foundation/Foundation.h>

@interface MySingleton : NSObject

+ (instancetype) sharedSingleton;

@end



MySingleton.m
---------------
#import "MySingleton.h"
@implementation MySingleton
static  MySingleton *shareSingleton = nil;

+(instancetype)sharedSingleton {
    static dispatch_once_t onceToken;
    //This will be called only once to make sure the singleton unique throughout the app.
    dispatch_once(&onceToken, ^{
        shareSingleton = [[MySingleton alloc] init];
    });
    return shareSingleton;
}
@end