Re: [avr-gcc-list] calling function pointers via pointers ?

[Dave Hansen]

From: Vincent Trouilliez <address@hidden>
[...]
> What more could I possibly want ? Well, there is one thing actually:
> the pointer points to a function, any function. However if the item is
> actually a sub-menu, then the 'menu_item' structure needs to store a
> pointer to a 'menu' structure, so that I know what sub-menu to run.
> So it would like this:
>
> typedef struct {
>         char    name[21];
>         void    (*fp) (uint8_t);
>         menu *sub_menu;   // I need to know what sub-menu to run !
> }menu_item;
>
>
> typedef struct menu {
>         char title[21];
>         uint8_t nb;
>         menu_item items[];
> }menu;
>
> But it's a bit strange no ? :-/ How can I declare a pointer of 'menu'
> type... even before said type has been declared ! The two structures
> would be interdependent... no solution in sight ! :o((((
>
> I guess this is crap code again... heeelp...

Not strange.  No crap.  You're just missing a feature.

C allows you to forward-declare a structure with a tag.  What you need is 
something like

  struct menu;    // Forward declaration

  typedef struct {
     char       name[21];
     void       (*fp) (uint8_t);
     struct menu *sub_menu;  // can't use typedef here
  }menu_item;

  typedef struct menu {
     char title[21];
     uint8_t    nb;
     menu_item items[];
  }menu;

Warning: untested code, but it should be close.  HTH,
  -=Dave