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Re: A quick memory (release) question

	
On Jan 31, 2006, at 5:23 AM, Clark Cox wrote:

On 1/31/06, Paul Harvey <email@hidden> wrote: 
Two quick examples:

1  NSMutableAttributedString *ns = [[NSMutableAttributedString alloc]
initWithString: chapterText];

2  NSString *lookFor = [[NSString alloc]initWithFormat:@"\n%d",i];

The rule for memory management says that if you obtain an object
through alloc, you have retained it and it must be manually released
at a later point.

Yet methods like initWithFormat create an autoreleased object don't
they?


No, they don't. Both of your examples were obtained from alloc,
period. So, you are responsible for releasing them.

Your confusing init methods (which don't generally allocate objects) with class methods that do allocate objects.

For example, if I call:

NSMutableDictionary *myDictionary = [[NSMutableDictionary alloc] initWithCapacity: 10];

Then I get back an object that I am responsible for releasing because I called "alloc"

However, if I call:

NSMutableDictionary *myDictionary = [NSMutableDictionary dictionaryWithCapacity: 10];

Then I get back an object that by the conventions of Cocoa has been autoreleased.

dictionaryWithCapacity is a class method that returns a new object. initWithCapacity is an instance method that you call when an object is new, but it is called on an already allocated object.

Does that make sense?

Scott

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References: 
 >A quick memory (release) question (From: Paul Harvey <email@hidden>)
 >Re: A quick memory (release) question (From: Clark Cox <email@hidden>)



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