纠正runtime获取metaclass方法的一个误区

看到网上有教程关于追踪一个Class的metaClass的方法，楼主使用了objc_getClass(const char*)，而正常应该使用object_getClass(Class)。

//实例方法

- (void)generateClassTest

{

Class newClass =objc_allocateClassPair([NSErrorclass],"TestClass",0);

class_addMethod(newClass,@selector(testMetaClass), (IMP)(testMetaClassImp),"v@:");

objc_registerClassPair(newClass);

idinstance = [[newClassalloc]initWithDomain:@"dynamic generate class" code:0 userInfo:nil];

[instanceperformSelector:@selector(testMetaClass)];

}

//c接口

void testMetaClassImp(id self,SEL cmd)

{

NSLog(@"this Object is %p\n\n",self);

NSLog(@"class is %@, super class is %@\n\n",[selfclass], [selfsuperclass]);

Class currentClass = [selfclass];

for(inti =0; i <4; i ++) {

NSLog(@"Following the isa pointer %d times gives %p\n\n", i, currentClass);

//currentClass = objc_getClass((__bridge void*)currentClass); // --wrong

currentClass =object_getClass(currentClass);// --right

}

NSLog(@"NSObject's class is %p\n\n",[NSObjectclass]);

//NSLog(@"NSObject's meta class is %p\n\n",objc_getClass((__bridge void*)[NSObject class])); // --wrong

NSLog(@"NSObject's meta class is %p\n\n",object_getClass([NSObjectclass]));// --right

Class metaClass =object_getClass([NSObjectclass]);// --right

//metaClass = objc_getClass((__bridge void*)[NSObject class]);// --wrong

NSLog(@"object_getClass([NSObject class])返回的%@ NSObject的meta类",class_isMetaClass(metaClass) ?@"是":@"不是");