What does the Asterisk * mean in Objective-C?

Is it true, that the Asterisk always means "Hey, that is a pointer!" And an Pointer always holds an memory adress?

(Yes I know for the exception that a * is used for math operation)

For Example:

NSString* myString;

or

SomeClass* thatClass;

or

(*somePointerToAStruct).myStructComponent = 5;

I feel that there is more I need to know about the Asterirsk (*) than that I use it when defining an Variable that is a pointer to a class.

Because sometimes I already say in the declaration of an parameter that the Parameter variable is a pointer, and still I have to use the Asterisk in front of the Variable in order to access the value. That recently happened after I wanted to pass a pointer of an struct to a method in a way like [myObj myMethod:&myStruct], I could not access a component value from that structure even though my method declaration already said that there is a parameter (DemoStruct*)myVar which indeed should be already known as a pointer to that demostruct, still I had always to say: "Man, compiler. Listen! It IIISSS a pointer:" and write: (*myVar).myStructComponentX = 5;

I really really really do not understand why I have to say that twice. And only in this case.

When I use the Asterisk in context of an NSString* myString then I can just access myString however I like, without telling the compiler each time that it's a pointer. i.e. like using *myString = @"yep".

It just makes no sense to me.

From stackoverflow

• As I said in my answer of your previous question, @"yep" is already a pointer, so there is no need of * before myString which is also a pointer. In this case, you assign pointers not values.

• an * is actually an operator to de-reference a pointer. The only time it means "hey i'm a pointer" is during variable declaration.

  Foo* fool // declare foo, a pointer to a Foo object
  &foo      // the memory address of foo
  *foo      // de-reference the pointer - gives the Foo object (value)
  

• mmattax well covered the distinction between declaration (as a pointer) and dereferencing.

  However, as to your point about:

  
    (*myVar).myStructComponentX = 5;
  

  to access a member of an instance of a C struct (as this is) you can do what you did , or more commonly you use the -> notation:

  
    myVar->myStructComponentX = 5;
  

  Objective-C is a little confusing here because it recently (in ObjC 2.0) introduced property syntax, which is a short cut for:

  
    int val = [myObject someIntProperty];
  

  and can now be written as:

  
    int val = myObject.someIntProperty;
  

  This is Objective C (2.0) syntax for accessing a property which you have declared (not an actual member variable), whereas your example was accessing a member of a C struct.

  Make sure you are clear on the difference.

• Not an answer, but a question: .h file:

  ...
  UIWebView *sections;
  UIWebView *feature;
  UIWebView *teasers;
  ...
  

  .m file:

  ...
  UIWebView *webView = nil
  ...
  if([section isEqualToString:@"Feature"]) {
      // Do I use
      webView = feature;
      // Or do I use
      webView = &feature;
      // Or do I use
      webView = *feature;
  }
  ...
  

  So in the above fragments, if I want to interact with webView as if it were feature, anything done to webView affects feature, which one do I do?: feature, *feature, or &feature?

  Sven : You should have asked a new question for this. But anyways, you use the first variant. You assign a pointer to another pointer. Second and third are errors: pointer = pointer-to-pointer or pointer = object don’t make sense.