Re: Where the hell is definition of struct id3_file????

Duh, makes all the sense in the world. My head is somewhere it shouldn't 
be :-). Got a big deadline and I am in panic mode :-(.

One more question, to build for Stongarm processor does configure support
--host= arm ? Using PXA255

tj

DervishD wrote:

>    Hi tj :)
>
> * tj <[email protected]> dixit:
>  
>
>>The first problem is the practically every call uses a pointer to a 
>>"struct id3_file" . Now, the problem is that there is no definition for 
>>id3_file structure in any .h file. I finally found it in file.c, a 
>>source file. How the hell are you supposed to use it in your app when 
>>the prototype is in a package source file?
>>    
>>
>
>    Well, it is called encapsulation. You use a pointer to the
>structure. You can use a pointer to an incomplete type, this is not a
>problem under C, AFAIK. Moreover, using this technique you are sure
>that nobody outside your source file is going to dereference the
>pointer. You have full encapsulation of the structure internals. This
>way, Rob can change the entire definition of the structure internals,
>change the implementation of the methods and you don't have to
>rewrite a line of code that uses libid3tag (or whatever). Thas a very
>good practice, object oriented. If you want to see another clear
>example, I have a small library containing a object oriented
>implementation (in C) of a multipurpose container, using the same
>techniques.
> 
>  
>
>>Seems that something is really broken here.
>>    
>>
>
>    Not at all. I would have provided something like:
>
>    typedef struct id3_file *ID3_FILE;
>
>    not more, for use in programs, thus occulting even the fact that
>this is a pointer. Now it is an object ;) I think that Rob is a good
>designer if he uses this kind of constructs. Without the above
>typedef, you can use the pointer to store a value, not more, not
>less, and you can pass it to functions, use it to store returned
>values, etc... Under C, all pointers share the same representation.
>The only problem (without the typedef above) is that you cannot do
>pointer arithmethic, so you cannot have arrays of id3_file structs,
>etc... This is the only flaw I see in this kind of code, and if you
>want encapsulation, that's the price to pay ;)
>
>    Anyway, I wouldn't use arrays of structs, I will use array of
>pointers, so you have pointer arithmethic and all that shit without
>exposing the internals of your structs.
>
>    Hope this helps :)
>
>    Raúl Núñez de Arenas Coronado
>
>  
>