[objectInstance init]; 对创建的实例对象,发送 init 消息,以减号(-)开头,进行初始化操作。 NSObject 是由meta class创建的对象。向对象发送某个消息的时候,编译器会调用底层的 obj_msgSend() C函数,从缓存和 方法列表中,寻找对象的函数指针(IMP),如果找到,则执行。否则继续根据一定的策略或者方式
instanceMethods[methodIndex]; SEL selector = method_getName(method); if (class_getInstanceMethod(targetClass, selector)) { continue; } IMP imp = method_getImplementation(method); const char *types = method_getTypeEncoding(method); class_addMethod(targetClass, selector, imp, types); } #1: ...
16+(BOOL)resolveInstanceMethod:(SEL)sel {17if(sel == NSSelectorFromString(@"sing")) {18//__unsafe_unretained Class cls:给哪个类添加方法。19//SEL name:添加什么方法。20//IMP imp:方法实现的函数。21//const char *types:方法类型。22class_addMethod([selfclass], sel, (IMP)sing,"v@:");23}...
typedef id (*IMP)(id, SEL, …); typedef signed char BOOL; #define YES (BOOL)1 #define NO (BOOL)0 #ifndef Nil #define Nil 0 /* id of Nil class */ #endif #ifndef nil #define nil 0 /* id of Nil instance */ #endif 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13....
{// v表示返回类型是void、@表示id、:表示SEL、@表示方法的具体参数class_addMethod(self,sel,(IMP)dynamicMethodIMP,"v@:@");return[superresolveInstanceMethod:sel];// 返回YES, 整个消息发送过程会重启}+(BOOL)resolveClassMethod:(SEL)sel{class_addMethod(self.class,sel,(IMP)dynamicMethodIMP,"v@:@")...
int nRet = base::singleton_instance<LeadRailCtrl>::instance()->HomeLR(nDevIndex); return nRet; } int CTRL_API GP_LR_Move(int nDevIndex, GP_LR_MOVE_DATA* pMoveData) { int nRet = base::singleton_instance<LeadRailCtrl>::instance()->MoveLR(nDevIndex, pMoveData); ...
因为当 Runtime 系统在 Cache 和方法分发表中(包括超类)找不到要执行的方法时,Runtime会调用resolveInstanceMethod: 或 resolveClassMethod: 来给程序员一次动态添加方法实现的机会。我们需要用 class_addMethod 函数完成向特定类添加特定方法实现的操作: void dynamicMethodIMP(idself, SEL _cmd) {...
(IMP)methodForSelector:(SEL)aSelector;+(IMP)instanceMethodForSelector:(SEL)aSelector;- (void)doesNotRecognizeSelector:(SEL)aSelector;- (id)forwardingTargetForSelector:(SEL)aSelector;- (void)forwardInvocation:(NSInvocation *)anInvocation;- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelect...
yet somehow it successfully calls DeckLinkDeviceArrived on an instance of a class it shouldn’t even know about. So the compiler has checked that our intended DiscoveryCallback matches the protocol that the SDK expects, but at runtime the compiled code instantiates a completely different implementat...
struct A { int i; int j; }; extern volatile A* pa; A getA() // returns an A instance copied from contents of pa { A a; a.i = pa - > i; a.j = pa - > j; return a; } struct B; // as above B b1{ GetA() }; B b2(b1); // error C2280 静态成员函数不支持 cv...