Hello Group,

(still undusting and porting an old framework for reliable
multicasting)

the following (original) code processes an error (error C2036: 'void
*' : unknown size)

int cntcp;
struct iovec *iov_set ;

// ... (determine size of cntcp)
iov_set->iov_base+=cntcp;

well, I understand very well that this will turn into an error, but
what do I do then? What was the original programmers goal? I guess he
tries (tried) to read the information received from the multicastgroup
and uses the cntcp variable to browse the iov_set->iov_base buffer.
The problem is that you cannot add an int to a void *, I think you
should add it to the address like this:

iov_set->iov_base = cntcp + &iov_set->iov_base;

this code doesnot give an error. Might my thinking be ok? Or does the
fact that iov_set is already a pointer on itself complicate things?

Thanks in advance,

--wim

[ Post a follow-up to this message ]

Wim Deprez wrote:
> Hello Group,
>
> (still undusting and porting an old framework for reliable
> multicasting)
>
> the following (original) code processes an error (error C2036: 'void
> *' : unknown size)
>
>      int cntcp;
>      struct iovec *iov_set ;
>
>       // ... (determine size of cntcp)
>      iov_set->iov_base+=cntcp;
>
> well, I understand very well that this will turn into an error, but
> what do I do then? What was the original programmers goal? I guess he
> tries (tried) to read the information received from the multicastgroup
> and uses the cntcp variable to browse the iov_set->iov_base buffer.
> The problem is that you cannot add an int to a void *, I think you
> should add it to the address like this:
>
>              iov_set->iov_base = cntcp + &iov_set->iov_base;
>
> this code doesnot give an error. Might my thinking be ok? Or does the
> fact that iov_set is already a pointer on itself complicate things?

That's very simple one:

((char *)iov-set->iov_base) += cntcp;

--
Lev Walkin
vlm@lionet.info

[ Post a follow-up to this message ]

Lev Walkin wrote:
> Wim Deprez wrote:
>
[...]
>
> That's very simple one:
>
> ((char *)iov-set->iov_base) += cntcp;
>

ah, I see it now :-) thanks a lot!,

--wim

[ Post a follow-up to this message ]