SingletonMacro.h

/** usage example
@implementation ABCPlayerManager
+ (instancetype)sharedPlayerManager {
    return TCM_SINGLETON(ABCPlayerManager);
}
@end
*/

#define TCM_SINGLETON(THECLASS) ({ \
    static THECLASS *s_sharedInstance = nil; \
    static dispatch_once_t onceToken; \
    dispatch_once(&onceToken, ^{ \
        s_sharedInstance = [THECLASS new]; \
    }); \
    s_sharedInstance;\
})