Re: @class create a new instance?
Re: @class create a new instance?
- Subject: Re: @class create a new instance?
- From: Kyle Sluder <email@hidden>
- Date: Mon, 25 Apr 2011 08:24:17 -0700
On Mon, Apr 25, 2011 at 8:02 AM, Rodrigo Zanatta Silva
<email@hidden> wrote:
> HI, someone said to me that *@class* directive create a new instance of the
> class automatic. I tried to find information about this, but didn't found.
They were wrong.
> For me, @class is only to solve cyclic includes. There are any side effect
> using it? The object variable is the same in this 2 example below, or there
> are some difference? The instance *instanceMyClass* will be the same of the
> class that send the pointer, right? And I will not lose any memory right?
You are correct. It's called a forward declaration, and is used to
resolve cyclic includes or reference class names in header files when
the actual definition isn't necessary.
Say you have MyClass.h:
// MyClass.h
@interface MyClass : NSObject {
OtherClass *ivar;
}
- (OtherClass *)myIvar;
@end
The compiler doesn't actually need to know the definition of
OtherClass; it just needs to know that OtherClass refers to a class.
So instead of #import "OtherClass.h", you could use @class OtherClass
at the top of MyClass.h; this makes compiling MyClass.h much faster.
--Kyle Sluder
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden