problem with singleton's methods in Objective-C - iphone

Question

I'm doing singleton and A cannot use methods on it... the type for arguments is not right apparently... and there are lots of mistakes (errors)...
Errors are in comment (in the code)
In a foreign Class :
[ [MySingleton sharedMySingleton] setAuth:#"test"]; //incompatible type for argument 1 of setAuth
NSLog([ [MySingleton sharedMySingleton] getAuth]); //Incompatible type for argument 1 os NSLOG
In my singleton's Classes :
#import <Foundation/Foundation.h>
#interface MySingleton : NSObject {
NSString *myToken;
}
+(MySingleton*)sharedMySingleton;
-(void)setAuth:(NSString) token;
-(NSString)getAuth;
#property (nonatomic, retain) NSString *myToken;
#end
... and ...
#import "MySingleton.h"
#implementation MySingleton
static MySingleton* _sharedMySingleton = nil;
#synthesize myToken;
+(MySingleton*)sharedMySingleton
{
#synchronized([MySingleton class])
{
if (!_sharedMySingleton)
[[self alloc] init];
return _sharedMySingleton;
}
return nil;
}
+(id)alloc
{
#synchronized([MySingleton class])
{
NSAssert(_sharedMySingleton == nil, #"Attempted to allocate a second instance of a singleton.");
_sharedMySingleton = [super alloc];
return _sharedMySingleton;
}
return nil;
}
-(id)init {
self = [super init];
if (self != nil) {
// initialize stuff here
}
return self;
}
-(void)setAuth:(NSString) token { // Can not use as abject as parameter to a method
myToken=token;// incomatible types in assignment
}
-(NSString)getAuth { // can not use an object as parameter to a method
return myToken;// incomatible types in return
} // control reaches end of non-void function
#end

Answer 1

-(void)setAuth:(NSString) token;
-(NSString)getAuth;
should be
-(void)setAuth:(NSString*) token;
// ^ note a pointer is needed
-(NSString*)getAuth;
// ^ note a pointer is needed
Also, your alloc is crazy. You actually invoke [super alloc] which will give you an object of the wrong type. Check out how to implement singleton in objective-c for iphone for better ways to do singletons.

Answer 2

Your header file is missing the * for the NSString type. For example, it should be :
-(void)setAuth:(NSString *) token;

Answer 3

Replace NSString with NSString* everywhere.