• Open Menu Close Menu
  • Apple
  • Shopping Bag
  • Apple
  • Mac
  • iPad
  • iPhone
  • Watch
  • TV
  • Music
  • Support
  • Search apple.com
  • Shopping Bag

Lists

Open Menu Close Menu
  • Terms and Conditions
  • Lists hosted on this site
  • Email the Postmaster
  • Tips for posting to public mailing lists
Re: How to avoid warning?
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: How to avoid warning?


  • Subject: Re: How to avoid warning?
  • From: Andy Lee <email@hidden>
  • Date: Tue, 22 Jan 2013 13:58:02 -0500

On Jan 22, 2013, at 1:26 PM, Jens Alfke <email@hidden> wrote:
>
> On Jan 22, 2013, at 9:24 AM, Dave <email@hidden> wrote:
>
>> Ok, cool, thanks for that, I still have the same problem though when I call the initWithManager.
>
> Others answered this already. To recap: The compiler needs to see a declaration of an -initWithManager: method before it parses this line. So you have to either #import the header that declares that method, or if there’s no such header, put a category interface at the top of this .m file that defines the method.

To spell it out even more... when the compiler sees this:

	myObj = [[myClass alloc] initWithManager:self];

...it knows that [myClass alloc] returns an id. Since it doesn't have any hint as to the class of that id, the compiler will be permissive/optimistic/trusting and allow any message to be sent to it without warning -- *IF* it has seen a declaration of that message somewhere, anywhere, for any class. So you need to force the compiler to see such a declaration. Even importing a totally unrelated class will do.

As has been suggested, you could import a class that declares initWithManager:. Or you could add your own declaration of something else -- it could be a category, a protocol, *anything* -- that declares the method.

// This works (category).
@interface NSObject (AvoidCompilerWarning)
- (id)initWithArg:(id)arg;
@end

// Or this also works (protocol).
@protocol AvoidCompilerWarning
- (id)initWithArg:(id)arg;
@end

--Andy


_______________________________________________

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


  • Follow-Ups:
    • Re: How to avoid warning?
      • From: Charles Srstka <email@hidden>
References: 
 >How to avoid warning? (From: Dave <email@hidden>)
 >Re: How to avoid warning? (From: Jens Alfke <email@hidden>)
 >Re: How to avoid warning? (From: Dave <email@hidden>)
 >Re: How to avoid warning? (From: Jens Alfke <email@hidden>)

  • Prev by Date: Re: How to avoid warning?
  • Next by Date: object.struct.element as lvalue
  • Previous by thread: Re: How to avoid warning?
  • Next by thread: Re: How to avoid warning?
  • Index(es):
    • Date
    • Thread