Bill Davidsen wrote:
Quiz for next Friday. What are these and what's the difference
between them:
int (*(**p)[])(int)
declare p as pointer to pointer to array of pointer to function (int)
returning int
and
int *(*(**p)[])(int)
declare p as pointer to pointer to array of pointer to function (int)
returning pointer to int
I would really want to see both a justification of method and
certificate of sanity to someone who actually used either. I can just
barely justify pointer to array of function returning int (state
machines), these look like something a compiler compiler would do.
I sort of recall using a pointer to an array of structs as the basic
data type for anything significant in C but I've mostly forgotten why.
I think sometimes it had to do with getting usable semantics to access
things in shared memory segments.
Pointer to struct is the heart of good linked lists, and a pointer to
array of struct is certainly a reasonably use. I certainly use arrays of
pointers to functions, both for state machines and and emulators, after
that it gets very hard to maintain.
But even if you only need the pointer to function (at first), you can
can put it inside a struct and write all the surrounding code to deal
with pointers to arrays of struct (even if there is only one...). I
don't think there is any real overhead to doing this and if you start
that way you can add elements to the struct when/if you realize you need
them without changing the outer loops that handle the pointers or the
memory allocation to store them.
--
Les Mikesell
lesmikesell@xxxxxxxxx
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