#import <Foundation/Foundation.h>

#undef  singleton
#define singleton( __class ) \
        property (nonatomic, readonly) __class * sharedInstance; \
        - (__class *)sharedInstance; \
        + (__class *)sharedInstance;

#undef  def_singleton
#define def_singleton( __class ) \
        dynamic sharedInstance; \
        - (__class *)sharedInstance \
        { \
        return [__class sharedInstance]; \
        } \
        + (__class *)sharedInstance \
        { \
        static dispatch_once_t once; \
        static __strong id __singleton__ = nil; \
        dispatch_once( &once, ^{ __singleton__ = [[self alloc] init]; } ); \
        return __singleton__; \
        }
@interface NSObject(RQSingleton)

@end