#import <malloc/malloc.h>
#import <objc/runtime.h>
NSObject *a = [[NSObject alloc] init];
NSLog(@"%lu %lu %lu",malloc_size((__bridge const void *)(a)),class_getInstanceSize([NSObject class]),sizeof(a));
结论 系统会分配16个字节 真正利用的只有8个字节
#import <malloc/malloc.h>
#import <objc/runtime.h>
NSObject *a = [[NSObject alloc] init];
NSLog(@"%lu %lu %lu",malloc_size((__bridge const void *)(a)),class_getInstanceSize([NSObject class]),sizeof(a));
结论 系统会分配16个字节 真正利用的只有8个字节