Question

I’m using a Singleton class and following is the code:

.h File: 

#import <Foundation/Foundation.h>


@interface Credential : NSObject {
    NSString *UID;
    NSString *UPASS;


}

@property(nonatomic,retain) NSString *UID;
@property(nonatomic,retain) NSString *UPASS;


static Credential *credential = NULL;

+(Credential*) sharedInstance;

/*
+ @property(nonatomic,retain) NSString *UID;
+ @property(nonatomic,retain) NSString *UPASS;
*/

@end

.m file:

#import "Credential.h"


@implementation Credential

@synthesize UID,UPASS;

-(void) dealloc{
    [UID release];
    [UPASS release];    
    [super dealloc];
}

+(Credential*) sharedInstance
{
    @synchronized(self)
    {
        if (credential == NULL) {
            credential = [[Credential alloc] init];
        }
    }
    return credential;
}

@end

The following line produces warning “defined but not used”

   static Credential *credential = NULL;

I couldn’t figure out that I’ve been using credential variable in .m file under “sharedInstance” function then why am I getting this warning?

A strange issue to me!

Answer 1

Does the problem go away when you move the static variable to the top of the implementation (.m) file? And on a related note, I think that you would benefit from getting rid of the singleton altogether.