iOS单例 宏定义

#define singleton_interface(className) + (className *)shared##className;


// @implementation
#define singleton_implementation(className) static className *_instance; + (id)allocWithZone:(NSZone *)zone { static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ _instance = [super allocWithZone:zone]; }); return _instance; } + (className *)shared##className { static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ _instance = [[self alloc] init]; }); return _instance; }

@interface AccountTool : NSObject
singleton_interface(AccountTool)
@end

@implementation AccountTool
singleton_implementation(AccountTool)
@end