Re: multiple declarations for method `length' ?
Re: multiple declarations for method `length' ?
- Subject: Re: multiple declarations for method `length' ?
- From: John Stiles <email@hidden>
- Date: Thu, 30 Dec 2004 10:36:27 -0800
On Dec 30, 2004, at 10:16 AM, j o a r wrote:
Please don't cross-post!
On 2004-12-30, at 19.05, Mark Dawson wrote:
When compiling this Obj-C line in XCode 1.5, I get the following
warning:
LengthParser.m:295: warning: multiple declarations for method `length'
short decimalLen = [[[NSUserDefaults standardUserDefaults]
objectForKey:NSDecimalSeparator] length];
What does this mean? It seems to run OK, producing the result (1 for
US system) that I'd expect…
If you check NSDictionary you'll find that:
- (id)objectForKey:(id)aKey
...it returns an "id" object. In other words, the compiler don't know
what type of object it is. When you call the method "length" on that
object, the compiler needs to guess what implementation to use. If
there is only one such method it's easy, but if there are several it's
not. You can help the compiler by casting:
NSString *str = [[NSUserDefaults standardUserDefaults] objectForKey:
NSDecimalSeparator];
short decimalLen = [str length];
or
short decimalLen = [(NSString *)[[NSUserDefaults standardUserDefaults]
objectForKey:NSDecimalSeparator] length];
j o a r
I thought one of the huge advantages of message-passing over function
calls was that you could send messages to "id" objects and objc_send
would sort out the details.
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Cocoa-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden