Getting error like "Implicit declaration of function 'IS_NOT_NIL_OR_NULL' is invalid in C99"

Question

When i am trying to restrict nill value in coredata i am getting error like

Implicit declaration of function 'IS_NOT_NIL_OR_NULL' is invalid in C99

Here is my code:

 if ([[context executeFetchRequest:fetchRequest error:NULL] count] == 0) {
        // Create a new managed object
        NSManagedObject *newDevice = [NSEntityDescription insertNewObjectForEntityForName:@"demo" inManagedObjectContext:context];
         if (IS_NOT_NIL_OR_NULL(self.Name))
    {
        [newDevice setValue:self.Name forKey:@"nameofentry"];
    } else 
     {
        // Handle else case .  get self.name value is null here .

     }

         if (IS_NOT_NIL_OR_NULL(self.WebsiteName))
    {
        [newDevice setValue:self.WebsiteName forKey:@"sitename"];
    } else 
     {
        // Handle else case .  get self.WebsiteName value is null here .

     }


          if (IS_NOT_NIL_OR_NULL(self.Feedlink))
    {
        [newDevice setValue:self.Feedlink forKey:@"urloffeed"];
    } else 
     {
        // Handle else case .  get self.Feedlink value is null here .

     }

        NSError *error = nil;
        // Save the object to persistent store
        if (![context save:&error]) {
            NSLog(@"Can't Save! %@ %@", error, [error localizedDescription]);
        }

    }

EDIT:

What is `IS_NOT_NIL_OR_NULL`? You can't just make up things. — rmaddy, Oct 27 '15 at 04:41
I want to restrict to enter NULL value in coredata. I have take a reference from this question. http://stackoverflow.com/questions/33339061/how-to-restrict-entry-of-null-value-in-coredata — krina_patel, Oct 27 '15 at 04:49
That must be some macro that person created. It's not a standard API. — rmaddy, Oct 27 '15 at 04:52
@rmaddy then how can i set it ? I didn't find any macro related to `IS_NOT_NIL_OR_NULL` in that answer . — krina_patel, Oct 27 '15 at 04:55
You've done what you can - ask that person what that macro is. — rmaddy, Oct 27 '15 at 04:57
@rmaddy ok. thank you.commented . now don't when i will get replay. — krina_patel, Oct 27 '15 at 05:00

score 2 · Accepted Answer · edited Oct 27 '15 at 06:51

2

Based on the referenced question and the answers where you found the reference to IS_NOT_NIL_OR_NULL, I'm guessing that one possible solution is to define the macro as:

#define IS_NOT_NIL_OR_NULL(x) (x && x != (id)[NSNull null])

Add this to the top of the .m file just after the import statements or add it to a common .h file that you can import.

Then code such as:

if (IS_NOT_NIL_OR_NULL(self.WebsiteName)) {

will become:

if ((self.WebsiteName && self.WebsiteName != (id)[NSNull null])) {

which I believe is what you are looking for.

edited Oct 27 '15 at 06:51

rob mayoff

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answered Oct 27 '15 at 05:06

rmaddy

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got warning like `comparision of distinct pointer type (NSstring *) and NSNull` – krina_patel Oct 27 '15 at 05:13
still getting this warning . i have updated #define as you edited. – krina_patel Oct 27 '15 at 05:32
It's working for me as shown in my answer. Copy and paste it. – rmaddy Oct 27 '15 at 05:35
1

You need to include the `(id)` cast in your code. I've updated this answer to include it. – rob mayoff Oct 27 '15 at 06:51
@krina_patel You added the macro (`#define`) but you aren't using it. – rmaddy Oct 27 '15 at 15:05
@robmayoff Thanks for fixing my typo but it should have had no bearing here since the OP should be using the referenced macro and not the fully expanded result. – rmaddy Oct 27 '15 at 15:12

score 0 · Answer 2 · answered Oct 27 '15 at 05:36

0

it just a macros defeine as .

 #define IS_NOT_NIL_OR_NULL(value)           (value != nil && value != Nil && value != NULL && value != (id)[NSNull null])

answered Oct 27 '15 at 05:36

Garry

407
2
15

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Checking `nil`, `Nil`, and `NULL` is redundant. Those are all the same. You only need one of those plus the `[NSNull null]` check. – rmaddy Oct 27 '15 at 05:40
@rmaddy check this out http://stackoverflow.com/questions/5908936/difference-between-nil-nil-and-null-in-objective-c – Garry Oct 27 '15 at 05:49
Yes, that verifies what I'm saying. – rmaddy Oct 27 '15 at 05:50

Getting error like "Implicit declaration of function 'IS_NOT_NIL_OR_NULL' is invalid in C99"

2 Answers2