<pre>#define SingletoH(methodName) +(instancetype)shared##methodName;//.h文件里实现

//.m文件里面实现

if __has_feature(objc_arc)//ARC情况下

define SingletoM(methodName) \

static __strong id _instace=nil;\

• (instancetype)allocWithZone:(struct _NSZone *)zone
  {
  if (_instace==nil) {
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
  _instace=[super allocWithZone:zone];
  });
  }
  return _instace;
  }\

• (instancetype)init
  {
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
  _instace = [super init];
  });
  return _instace;
  }\

• (instancetype)shared##methodName
  {
  return [[self alloc] init];
  }

else//非ARC情况下

define SingletoM(methodName) \

static id *_instace=nil;\

• (instancetype)allocWithZone:(struct _NSZone *)zone
  {
  if (_instace==nil) {
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
  _instace=[super allocWithZone:zone];
  });
  }
  return _instace;
  }\

• (instancetype)init
  {
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
  _instace = [super init];
  });
  return _instace;
  }\

• (instancetype)shared##methodName
  {
  return [[self alloc] init];
  }\

• (oneway void)release
  {
  }\
• (instancetype)retain
  {
  return self;
  }\
• (NSUInteger)retainCount
  {
  return 1;
  }

endif

</pre>