Question

好吧我说我的功能如下：

-(NSNumber *)calculate{
  NSNumber *myNum = [[[NSNumber alloc]initWithInt:5] autorelease];
  return myNum;
}

myNum何时会被释放？每当我调用compute时，myNum都会被创建并添加到堆栈中吗？

还说我有一个属性：

@property (nonatomic, retain) NSMutableArray *inputsArr;

我把它合成为：

@synthesize inputsArr = _inputsArr;

我在其中一个mu函数的代码中分配并启动它。我该如何释放这段记忆？ CoaCoa内存管理的任何指南...我只能找到真正令人困惑或明显的指南.. 提前致谢

Answer 1

自动释放池是线程本地堆栈 - 您可以推送它们。当池被销毁时，延迟的release消息将被发送到对象。

考虑一下：

NSAutoreleasePool * pool = [NSAutoreleasePool new];
NSNumber * n = [NSNumber numberWithDouble:1.0/17.0]; << n is autoreleased
[n self]; << OK!
[pool release]; << n is messaged release
[n self]; << BAM!

所以'何时'真的取决于自动释放池的构建方式 - 但总是可以确保你的对象比本地池更长，所以这绝不是限制：

NSAutoreleasePool * pool = [NSAutoreleasePool new];
NSNumber * n = [NSNumber numberWithDouble:1.0/17.0]; << n is autoreleased
[n self]; << OK!
[n retain];
[pool release]; << n is messaged release
[n self]; << OK!
[n release];
[n self]; << BAM!

以上是你应该依赖的。在一些现实世界的情况下，一个对象可能仍然存在，你期望“BAM！”，但你永远不应该依赖“好吧，它本应该被摧毁，但似乎工作正常”

Answer 2

NSApplication类在初始化期间和事件循环内部 - 特别是在其初始化（或sharedApplication）和run方法中设置自动释放池（NSAutoreleasePool类的实例）。通常自动释放池在事件循环结束时弹出，但这取决于您或应用程序如果您要使用大量临时对象（自动释放/来自方便方法），您可能需要考虑创建自己的短期自动释放池以避免临时内存峰值。Autorelease对象添加到最新的自动释放要创建的池。

 NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; // create your own little autorelease pool
  // these objects get added to the autorelease pool you created above 
  NSNumber *aNumber1 = [NSNumber numberWithFloat:1]; // refcount is 1, you are not owner, will be automatically released
  NSNumber *aNumber2 = [NSNumber numberWithFloat:2]; // refcount is 1, you are not owner, will be automatically released
  NSNumber *aNumber3 = [NSNumber numberWithFloat:3]; // refcount is 1, you are not owner, will be automatically released
  NSNumber *aNumber4 = [NSNumber numberWithFloat:4]; // refcount is 1, you are not owner, will be automatically released
  NSNumber *aNumber5 = [NSNumber numberWithFloat:5]; // refcount is 1, you are not owner, will be automatically released
  NSNumber *aNumber6 = [NSNumber numberWithFloat:6]; // refcount is 1, you are not owner, will be automatically released

  // ... do a bunch of stuff with all objects above.
  ...      

  [pool release]; // all objects added to this pool (the ones above) are released

看看Memory Management with Objective C / Cocoa / iPhone。

NSautorelease什么时候发布这个？

2 个答案: