Question

I am wondering, what specifically @interface section of a header file should hold?

From the examples i saw it seems that it is used to declare instance variables. Accessors and other methods seem to be outside of it.

Please clarify

Answer 1

@interface has at least two contexts: declaring a class and declaring a category. A class declaration looks like the following (with the bracketed stuff being optional):

@interface Class [: Superclass]
{
    [fields]
}
[methods]
@end

A category declaration looks roughly the same, but has no fields zone:

@interface Class (CategoryName)
[methods]
@end

So, the @interface line must be followed by braces in the case of a class declaration, and the fields of the class should be enclosed within. You put methods after the braces.