iOS——runtime

void objc_setAssociatedObject(id object,constvoid *key,id value, objc_AssociationPolicy policy)

id objc_getAssociatedObject(id object,constvoid *key)

objc_allocateClassPair(superClass, className, size_t bytes);

//创建className类，继承自superClass，空间bytes

objc_registerClassPair(Class cls) 

objc_disposeClassPair(Class cls)

Class object_getClass(id obj)

//获取对象的类实例， 获得isa指针

Class objc_getClass(constchar *name)

Class object_setClass(id obj, Class cls)

BOOL object_isClass(id obj)

const char *object_getClassName(id obj)

Class objc_getMetaClass(constchar *name)

id object_copy(id obj, size_t size)

id object_dispose

//销毁对象

const char *NSGetSizeAndAlignment(constchar *typePtr, NSUInteger *_Nullable sizep, NSUInteger *_Nullable alignp)    

//取得对象的大小