Objective C - Declaration Error - please explain

Question

@interface Connections()
{
   static Connections *this;
}
@end

The above piece of code in .m file throwing compiler error

Type name does not allow storage class to be specified

at the same time when the

static

key word is removed it works well - which so obvious. Purpose : I want "Connections" instance static and private.

Why is this behavior, please help.

Answer 1

You cannot declare class-level variables in Objective-C classes; instead you need to "hide" them in the implementation file, often giving them static-scope so they cannot be accessed externally.

Connections.m:

#import "Connections.h"

static Connections *_sharedInstance = nil;

@implementation Connections

...

@end

And if this is a singleton, you typically define a class-level accessor to create the singleton upon first use:

+ (Connections *)sharedInstance
{
    if (_sharedInstance == nil)
    {
        _sharedInstance = [[Connections alloc] init];
    }
    return _sharedInstance;
}

(and you'll need to add the declaration in the .h file):

+ (Connections *)sharedInstance;