对象的引用计数看似有用，实则不然，因为任何给定的时间点上的“绝对保留计数”都无法反应对象生命期的全貌 ARC环境中，已将retainCount废弃
=%lu",(unsigned long)testRetain.retainCount); //2 NSLog(@"user.tRetain.retainCount=%lu",(unsigned...= testRetain2; NSLog(@"testRetain.retainCount=%lu",(unsigned long)testRetain.retainCount); //1...NSLog(@"testRetain2.retainCount=%lu",(unsigned long)testRetain2.retainCount); //4294967295 NSLog(@"...long)testRetain3.retainCount); //1 [testRetain3 retain]; NSLog(@"testRetain3.retainCount=%lu"...:testRetain3]; NSLog(@"testRetain3.retainCount=%lu",(unsigned long)testRetain3.retainCount); //3
s2.retainCount=%d",[s1 retainCount],[s2 retainCount]); [s1 autorelease];//retainCount仍为1 NSLog(...@"s1.retainCount=%d,s2.retainCount=%d",[s1 retainCount],[s2 retainCount]); [s2 retain];//retainCount...=2 [s2 autorelease];//retainCount仍为2 NSLog(@"s1.retainCount=%d,s2.retainCount=%d",[s1 retainCount...[461:a0f] s1.retainCount=1,s2.retainCount=1 2011-02-24 13:49:22.566 MemoryManage[461:a0f] s1.retainCount...=1,s2.retainCount=1 2011-02-24 13:49:22.567 MemoryManage[461:a0f] s1.retainCount=1,s2.retainCount=2 2011
= %d",(int)string.retainCount);//retainCount = -1 [string retain]; //没用 NSLog(@"str常量的retainCount =...%d",(int)string.retainCount);//retainCount = -1 运行结果： 1 2 2014-08-03 20:01:31.360 Memory...*string2 = [NSString stringWithString:string]; NSLog(@"传入字符串常量 RetainCount = %d", (int)string2.retainCount...= %d",(int)string1.retainCount); //retainCount = 3 NSLog(@"传入的变量RetainCount = %d", (int)string3.retainCount...);//retainCount = 3 运行结果： 1 2 3 2014-08-03 20:18:37.240 Memory[2499:303] 传入字符串常量 RetainCount
每个对象(特指：类的实例)内部都有一个retainCount的引用计数，对象刚被创建时，retainCount为1，可以手动调用retain方法使retainCount+1，同样也可以手动调用release...sample.retainCount=%d",[_sample retainCount]);//2 [_sample retain]; NSLog(@"_sample.retainCount=%...d",[_sample retainCount]);//3 [_sample release]; NSLog(@"_sample.retainCount=%d",[_sample retainCount...，当前引用计数:1 NSLog(@"_sample.retainCount=%d",[_sample retainCount]);//1，注：即便是在析构函数执行后，如果立即再次引用对象的retainCount...@"is nil":@"is not nil",[s retainCount]);//s is not nil,retainCount=1 //NSLog(@"s %@,retainCount=%d"
因为OC中用引用计数的方式来进行内存管理的所以我们也可以通过观察对象retainCount的变化来分析对象之间是否是深拷贝还是浅拷贝。...(@"str1 = %@, retain_str1.retainCount = %d",str1, (int)str1.retainCount); //把str通过copy的方式把值赋给str2 NSString...*str2 = [str copy]; NSLog(@"str2 = %@, copy_str2.retainCount = %d", str2, (int)str2.retainCount);...= %@, retain_s1_retainCount = %d", s1, (int)s1.retainCount); //把s通过copy的方式把值赋给s2; NSMutableString...[0] = %@, copy_array.retainCount = %d", array2[0], (int)array2.retainCount); //把array通过mutableCopy
我们逐行分析一下 第一行，alloc一次，imgView对象retainCount为1， 第二行，addSubview一次，此方法会把你传过去的对象retain一次，那么此时它的retainCount为...第三行，调用release方法，此处释放对imgView的所有权，retainCount减1。 到语言句尾imgView的所有者只剩下self.view，并且它的retainCount仅为1。
NSString *a = [NSString stringWithFormat:@"abc"]; NSLog(@"a retainCount = %ld",[a retainCount]);...NSString *b = [a copy]; NSLog(@"a retainCount = %ld",[a retainCount]); NSString *c = [a mutableCopy...; NSLog(@"%p,%p,%p",a,b,c); 结果 2019-09-12 13:54:58.109757+0800 Copy MutableCopy[13700:49429440] a retainCount...= -1 2019-09-12 13:54:58.109876+0800 Copy MutableCopy[13700:49429440] a retainCount = -1 2019-09-12
属性.为内存计数器 使用一次retainCount+1,当retainCount为0时 释放该对象指向的内存 贴出部分代码 // Object.h #ifndef Object_h #define...Object_h #include //定义结构体 typedef struct Object{ int retainCount; }Object; //宏定义方法 方便书写...++; // printf("retain计数+1 = %d\n",obj->retainCount); } void objectRelease(Object *obj) { obj...->retainCount --; if (obj->retainCount <= 0) { free(obj); } // printf("retain计数-1...= %d\n",obj->retainCount); } //获得当前计数 int getRetainCount(Object *obj) { return obj->retainCount;
值加 1； release既是把retainCount值减 1 dealloc只有在 retainCount = 0 的时候，由系统自动调用 autorelease是把对象加进自动释放池中，由系统自动为池中的对象发送...引用计数：就是分配的 内存区块 被 多少个 OC对象所持有（掌管；保持且拥有），间接表示就是retainCount值的大小。...对象... , 请看下表： OC操作方法 对象的操作 retainCount alloc/new/copy/mutablecopy等 生成并持有对象 1？...勾选僵尸对象检测 情况 1：过快释放了对象（不要理retaiinCount把注意力放在对象被持有的个数上） retainCount的补充： ?...运行结果 疑问：mArrayCopy的retainCount是2 ?被持有者有两个？ ?
synthesize flag; - (NSString *) description { return ([NSString stringWithFormat:@"I am engine %d,my retainCount...=%d",flag,[self retainCount]]); } // description -(void) dealloc { NSLog(@"this engine %d is going...报废 [engine2 release];//新引擎engine2当然也不再需要了 同样有二个问题： 2.1 engine1先被new了一次，然后在setEngine中又被retain了一次，也就是说其retainCount...为2，虽然代码中后来release了一次，但是也只能让retainCount减到1，并不能销毁！...Engine *engine1 = [Engine new];//engine1.retainCount=1 engine1.flag = 1; Car *car1 = [Car new]; car1
内存管理 图片 内存布局 图片 什么是引用计数 Objective-C通过retainCount的机制来决定对象是否需要释放。...每次runloop迭代结束后，都会检查对象的retainCount，如果retainCount等于0，就说明该对象没有地方需要继续使用它，可以被释放掉了。...无论是手动管理内存，还是ARC机制，都是通过对retainCount来进行内存管理的。 内存中每一个对象都有一个属于自己的引用计数器。...引用计数器的管理 图片 引用计数的存储 图片 SideTable 图片 图片 图片 底层的实现 retainCount 图片 release 图片 RefCountMap的原理 通过计算对象地址的哈希值
is %lu",self.name,[self retainCount]]; } - (void)dealloc { self.name = nil; self.family = nil...is 3", "swift's retainCount is 3", "android's retainCount is 3", "java's retainCount is 3", "ruby's...retainCount is 3" ) 可以看出每个person的retainCount为3，因为family持有person,person持有family，如果我们运用NSHashTable...is 2", "swift's retainCount is 2", "android's retainCount is 2", "java's retainCount is 2", "ruby's...retainCount is 2" ) 可看出，已解决循环引用 2、宏定义魔法 先看一下系统的KVO方法 [testPerson addObserver:self forKeyPath:@"
(str1)=%lu,retainCount(str2)=%lu",[str1 retainCount],[str2 retainCount]); //结果：retainCount(str1)=...(str1)=%lu,retainCount(str3)=%lu",str1.retainCount,str3.retainCount); //结果：retainCount(str1)=2,retainCount...(str3)=%i",str3.retainCount); //结果：1 [str3 retain]; NSLog(@"retainCount(str3)=%i",str3.retainCount...(str4)=%i",str4.retainCount); //结果：1 [str4 retain]; NSLog(@"retainCount(str4)=%i",str4.retainCount...(str5)=%i",str5.retainCount); //结果：1 [str5 retain]; NSLog(@"retainCount(str5)=%i",str5.retainCount
2 3 4 -(id)mutableCopyWithZone:(NSZone *)zone { return self; } 5.防止用户把创建的单例dealloc,我们需要重写retainCount...方法 1 2 3 4 5 //重写retainCount方法，防止被dealloc,返回最大值 -(NSUInteger) retainCount { return NSUIntegerMax;...SingletonClass *single6 = [single1 retain]; [single1 release]; [single1 singletonFunction]; NSLog(@"single_retainCount...= %lu", single1.retainCount); //输出地址 NSLog(@"getInstance single1_P = %p", single1); NSLog(@"new...2014-08-07 16:04:44.207 Memory[20664:303] single_retainCount = 18446744073709551615 2014-08-07 16:04:
实现 NSCopying 协议，覆盖 release，autorelease，retain，retainCount 方法，以此确保单例的状态。...} - (id)copyWithZone:(NSZone *)zone { return segtonInstance; } //覆盖 release，autorelease，retain，retainCount...方法方法 //返回本身 -(id)retain { return self; } -(NSInteger)retainCount { return UINT_MAX; } -(id
NSLog([NSString stringWithFormat:@"Retain Count:%i", [someObject retainCount]]); 对象的retainCount方法就会反回这个对象的
我们逐行分析一下 第一行，alloc一次，imgView对象retainCount为1， 第 二行，addSubview一次，此方法会把你传过去的对象retain一次，那么此时它的retainCount...第三行，调用release方法，此处释放对imgView的所有权，retainCount减1。 到语言句尾imgView的所有者只剩下self.view，并且它的retainCount仅为1。
define FAST_IS_SWIFT (1UL<<0) // class or superclass has default retain/release/autorelease/retainCount...1UL<WORD_BITS-1)) #define SIDE_TABLE_RC_SHIFT 2 #define SIDE_TABLE_FLAG_MASK (SIDE_TABLE_RC_ONE-1) 每个retainCount...都是size_t，是无符号整形 所以根据上面的宏定义，一个retainCount的位区域划分如下图 ?...三、retainCount、dealloc的实现 retainCount实现 - (NSUInteger)retainCount { return ((id)self)->rootRetainCount...(); } uintptr_t objc_object::sidetable_retainCount() { SideTable& table = SideTables()[this];
#import "MyObject.h" @interface MyObject(){ int _index; } @end @implementation MyObject void retainCount...init{ self=[super init]; if(self){ // typeof(self) __block wself=self; retainCount
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