nsautoreleasepool 范围内的 return 语句

Question

假设我有以下场景：

- (void)someFunction:(id)param {

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    NSObject *objectA = [[NSObject alloc] init];
    [objectA doStuff];  // Don't need to release objectA because of the pool

    if (!someValue) {
        [pool release];   // Doubt here
        return;
    }

    NSObject *objectB = [[NSObject alloc] init];
    [objectB doStuff];  // Don't need to release objectB because of the pool

    [pool release];
}

以这种方式从池块内部返回是否正确？

Answer 1

简短的回答：是的。

长答案：没有显式释放而被放弃的池在其嵌套的自动释放池（通常是当前线程的顶部自动释放池）被释放时被释放。

顺便说一句，这是错误的：

NSObject *objectA = [[NSObject alloc] init];
[objectA doStuff];  // Don't need to release objectA because of the pool

您仍然必须显式地释放分配的对象：

NSObject *objectA = [[NSObject alloc] init];
[objectA doStuff];
[objectA release];

或者通过将它们添加到自动释放池中：

NSObject *objectA = [[[NSObject alloc] init] autorelease];
[objectA doStuff];