Releasing an NSDictionary (or other NSObjects) that are a return value.

Let us say that I have a method like this:

- (NSDictionary*)getBigDictionaryOfSecrets
{

NSDictionary *theDic = [[NSDictionary alloc] init];
theDic = // insert conte开发者_运维技巧nts of dictionary

return theDic;
}

How and where should one properly release this?

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Try return [theDic autorelease]. This will not release the dictionary immediately, allowing the caller to retain it.

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You either autorelease it or you document very well that the caller is responsible for releasing it.

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This is exactly what autorelease is for. Do something like this:

- (NSDictionary*)bigDictionaryOfSecrets 
{ 
    NSDictionary *theDic = [[NSDictionary alloc] initWithObjectsAndKeys:@"bar", @"foo", nil];

    return [theDic autorelease];
}

Read more about autorelease in the Memory Management Programming Guide.

---

Alternatively to the answers provided, instead of using autorelease you could do something like this:

- (void)populateBigDictionaryOfSecrets(const NSMutableDictionary*)aDictionary
{
    // insert contents of dictionary
}

And create/release the dictionary in the class/method where it will be used.

---

Setting the return object on autorelease should work. Remember that the receiver must retain the returned object.

- (NSDictionary*)getBigDictionaryOfSecrets 
{ 
  NSDictionary *theDic = [[NSDictionary alloc] init];
  theDic = // insert contents of dictionary

  return [theDic autorelease];
}