BlackMagic.h

#define CLASS_PROPERTY_INTERFACE(TYPE, METHOD, CMETHOD) \
+ (TYPE) METHOD; \
+ (void) set##CMETHOD:(TYPE)val; \

#define CLASS_PROPERTY_IMPLEMENTATION(TYPE, METHOD, CMETHOD) \
static TYPE _##METHOD; \
+ (TYPE) METHOD \
{ @synchronized(self) { return _##METHOD; } } \
+ (void) set##CMETHOD:(TYPE)val \
{ @synchronized(self) { _##METHOD = val; } } \

Usage

// Setter
User.me = currentUser;

// Getter
User.me

User.h

@interface User : NSObject

CLASS_PROPERTY_INTERFACE(User *, me, Me)

@end

User.m

@implementation User

CLASS_PROPERTY_IMPLEMENTATION(User *, me, Me)

@end