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Re: Void pointer arithmetic
On Thu, 2007-05-17 at 22:29 -0700, Michael Eager wrote:
> Sven Eschenberg wrote:
> > Hi list,
> >
> > Long time ago I wrote a small application, well back when g++ didn't
> > even insist on std::cout. Now, since I upgrade g++ and tried to compile
> > the application, g++ threw errors and warnings in masses. Most of the
> > stuff I could fix, but I am stuck with the following problem:
> >
> > /usr/include/linux/netfilter_ipv4/ip_tables.h: In function
> > 'xt_entry_target* ipt_get_target(ipt_entry*)':
> > /usr/include/linux/netfilter_ipv4/ip_tables.h:225: error: pointer of
> > type 'void *' used in arithmetic
> > /usr/include/linux/netfilter_ipv4/ip_tables.h:225: error: invalid
> > conversion from 'void*' to 'xt_entry_target*'
> >
> > Is there any chance of fixing the problem without tweaking the kernel
> > includes (the running kernel is kinda ancient, but updates are a little
> > difficult)?
>
> Cast the (void *) to (char *).
>
> It's not clear what the type of xt_entry_target is. If it
> is a pointer, then there should be no problem converting.
>
>
Well, the funny thing is, the pointer is casted to void *, and then
returned, the inline functions return type is a different type anyway,
so I changed it to the return type which pretty much does the job.
Still, feels uncomfortable, that I had to change the header (which is
from a pretty recent kernel headers package).
-Sven