* Void pointer arithmetic
@ 2007-05-17 21:45 Sven Eschenberg
2007-05-18 5:29 ` Michael Eager
0 siblings, 1 reply; 3+ messages in thread
From: Sven Eschenberg @ 2007-05-17 21:45 UTC (permalink / raw)
To: gcc-help
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)?
Thnx
-Sven
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Void pointer arithmetic
2007-05-17 21:45 Void pointer arithmetic Sven Eschenberg
@ 2007-05-18 5:29 ` Michael Eager
2007-05-18 11:01 ` Sven Eschenberg
0 siblings, 1 reply; 3+ messages in thread
From: Michael Eager @ 2007-05-18 5:29 UTC (permalink / raw)
To: Sven Eschenberg; +Cc: gcc-help
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.
--
Michael Eager eager@eagercon.com
1960 Park Blvd., Palo Alto, CA 94306 650-325-8077
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Void pointer arithmetic
2007-05-18 5:29 ` Michael Eager
@ 2007-05-18 11:01 ` Sven Eschenberg
0 siblings, 0 replies; 3+ messages in thread
From: Sven Eschenberg @ 2007-05-18 11:01 UTC (permalink / raw)
To: Michael Eager; +Cc: gcc-help
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
^ permalink raw reply [flat|nested] 3+ messages in thread
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2007-05-17 21:45 Void pointer arithmetic Sven Eschenberg
2007-05-18 5:29 ` Michael Eager
2007-05-18 11:01 ` Sven Eschenberg
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