Complete use examples and destruction macro definitions of ios single interest

//This section below is used directly in the macro test#define SYNTHESIZE_SINGLETON_FOR_HEADER(className) \
\
+ (className *)sharedInstance;\
+ (void)destroyInstance;
//OnceToken = 0 before singleton generation, onceToken = -1 after singleton generation, and then keep the value of -1. After knowing this, I think you should have a idea.#define SYNTHESIZE_SINGLETON_FOR_CLASS(className) \
\
static className *shared##className = nil; \
static dispatch_once_t onceToken;\
+ (className *)sharedInstance\
{\
 return [[self alloc] init];\
}\
+ (className *)allocWithZone:(struct _NSZone *)zone\
{\
 dispatch_once(&onceToken, ^{\
  shared##className = [super allocWithZone:zone];\
 });\
 return shared##className;\
}\
- (className *)copyWithZone:(NSZone *)zone\
{\
 return shared##className;\
}\
- (className *)mutableCopyWithZone:(NSZone *)zone\
{\
 return shared##className;\
}\
+ (void)destroyInstance {\
 shared##className = nil;\
 onceToken = 0;\
}\

//Usage, be careful to follow the NSCoping and NSMutableCopying protocolsimport <Foundation/>
@interface YNHTUserModel : NSObject<NSCopying,NSMutableCopying>
SYNTHESIZE_SINGLETON_FOR_HEADER(YNHTUserModel);
@property (nonatomic,copy) NSString* inviter_id;//Inviter ID@property (nonatomic,copy) NSString* token;
@property (nonatomic,copy) NSString* nick_name;
@end

#import ""
@implementation YNHTUserModel
SYNTHESIZE_SINGLETON_FOR_CLASS(YNHTUserModel);

@end