内存开销非常小：基本上每个接口需要额外4个字节（对象实例数据里虚函数表指针），加上引用计数的4个字节。

Overhead in memory is very small: You basically have a 4- byte overhead per interface (the vtable pointers in the object's instance data) plus 4 bytes for the reference counter.

youdao

内存开销非常小：基本上每个接口需要额外4个字节（对象实例数据里虚函数表指针），加上引用计数的4个字节。

Overhead in memory is very small: You basically have a 4- byte overhead per interface (the vtable pointers in the object's instance data) plus 4 bytes for the reference counter.

youdao