> | 
> | Why the parameter 'dp' to DIRENT_NAMEOFF? Why wouldn't
> | it just boil down to a constant? ((struct dirent *)0)
> 
> Because I can use this macro with struct dirent, struct dirent12, 
> and struct direct. Otherwise I would need 3 macros.

#define _DIRENT_RECLEN(dp, namlen) \     
    ((_DIRENT_NAMEOFF(dp) + (namlen) + 1 + 0xf) & ~0xf)

Does this 0xF alignment hold for all variants of dirent?