Re: passing address of an object of type id

[glen e. p. ropella]

> I created a list of type id just like in heatBugList. Now, I want ot pass
> its address to some method. I'm doing it like this.
> 
> in *.h file
> -----------
> id partList;
> 
> in *.m file
> -----------
> 
> -setPartList: (id *)p{
>  partList=p;
>  return self;
>  }
> 
> My program is compiling with a warning message "assignment from
> incompatible pointer type". Can any one explain it to me. I appreciate
> your time. I haven't seen any example in the above format. So, I guess I
> messed it up.
> 
> -Naga Krothapalli
> address@hidden

Hi Naga.

Well, it looks to me like partlist is of type "id," not "id *,"
which means "pointer to an id."

What you may be missing is the fact that (id) is a pointer already.
Using it to pass things into functions is analogous to declaring a
type in C like:

struct xyz_type{
        int booga;
        float ooga;
};
typedef struct xyz_type *p_xyz_type;
main()
{
        p_xyz_type pxyz;
        struct xyz_type booga;
        pxyz = &booga;
       ....
}

This makes p_xyz_type a pointer to a structure of type xyz.

In objective C, an "id" is a pointer to an object.  An object
is, itself, a structure.

So, basically, just take the "*" out of the setPartList definition
and prototype and it should work.

glen