Re: Question about memory management

[Maxthon Chan]

Just asking, with ARC, is this a good choice on implementing singleton?

//Singleton.h

#import <Foundation/Foundation.h>

@interface Singleton : NSObject

+ (instancetype)defaultSingleton;

// …

@end

extern Singleton *DefaultSingleton // Of course this is optional

// Singleton.m

Singleton *DefaultSingleton

@implementation Singleton

+ (instancetype)defaultSingleton

{

if (!DefaultSingleton)

DefaultSingleton = [[self alloc] init];

return DefaultSingleton;

}

// …

@end

在 2013-6-7，上午1:31，Ivan Vučica <address@hidden> 写道：

It depends on how the object is used -- in this case (without looking at the code), it sounds like it's a typical singleton approach.

On Wed, Jun 5, 2013 at 8:07 AM, Germán Arias <address@hidden> wrote:

Thanks for the explanation. I knew about static variables with strings (like @"hello").
And that these don't should be released. But I did not know that this applies to
other objects.

Thanks.
Germán.

On 2013-06-04 23:55:15 -0600 Graham Lee <address@hidden> wrote:

> That's returning a shared static instance of the GSComboWindow class, so it's
> expected that it isn't released. It's also outside of the NSComboBoxCell
> class, so as far as NSComboBoxCell instances are concerned, they should obey
> standard memory management rules:
>
> - if you got an object via +alloc, -copy or -new, you own it and should
> -release or -autorelease it later.
> - if you didn't, you don't own it unless you -retain it
> - if you did neither of these, don't -release or -autorelease it.
>
> NSComboBoxCell is consistent with these rules.
>
> Graham.
>

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Ivan Vučica - address@hidden

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