Re: [Qemu-devel] [PATCH] pixman: remove -Wredundand-decls

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 04/16/2013 08:48 AM, Alexey Kardashevskiy wrote:
> On 04/16/2013 01:55 AM, Markus Armbruster wrote:
>> Alexey Kardashevskiy <aik@ozlabs.ru> writes:
>>
>>> On 04/15/2013 10:57 PM, Markus Armbruster wrote:
>>>> Alexey Kardashevskiy <aik@ozlabs.ru> writes:
>>>>
>>>>> On 04/15/2013 08:01 PM, Peter Maydell wrote:
>>>>>> On 15 April 2013 10:50, Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
>>>>>>> /home/alexey/pcipassthru/qemu-impreza/../lib4qemu/usr/include/assert.h:67:13:
>>>>>>>
>>>>>>> error: redundant redeclaration of '__assert_fail'
>>>>>>> [-Werror=redundant-decls]
>>>>>>> /home/alexey/pcipassthru/qemu-impreza/../lib4qemu/usr/include/assert.h:67:13:
>>>>>>>
>>>>>>> note: previous declaration of '__assert_fail' was here
>>>>>>> /home/alexey/pcipassthru/qemu-impreza/../lib4qemu/usr/include/assert.h:72:13:
>>>>>>>
>>>>>>> error: redundant redeclaration of '__assert_perror_fail'
>>>>>>> [-Werror=redundant-decls]
>>>>>>
>>>>>> This copy of assert.h seems to be broken. The declarations
>>>>>> should be guarded (by _ASSERT_H_DECLS in my system's copy).
>>>>>
>>>>> Debian? It uses eglibc which is fork (or clone?) of glibc.
>>>>>
>>>>>> If it's widespread we might have to work around this.
>>>>>
>>>>> It is in fedora 18 and glibc's git master branch. Why "if"?
>>>>
>>>> It's in Fedora 17, too, but I *don't* get a warning.  Suspecting your
>>>> compiler.  --version?
>>>
>>>
>>> powerpc64-linux-gcc 4.6.3, 4.7.2, 4.8.0, all the same. I'll try to
>>> track it down tomorrow why it all works when host and target are the
>>> same (pretty sure this is the cse) but I just do not get it... It is
>>> just me who sees obvious error in assert.h which is caused by
>>> -Wno-redundant-decls? Even if you do not hit this now, you will get
>>> there eventually.
>>
>> I don't doubt your gcc+libc is in error.  I just don't want to lose a
>> useful warning because of that.
>  >
>> Workaround: configure --disable-werror
>
> This workaround does NOT work if pragmas used. "#pragma GCC diagnostic
> error "-Wredundant-decls"" re-enables warnings as errors.


Kind of offtopic but still...

I think this is just beautiful. Fedora18, x86_64, NO cross compiler. gcc 
does not apply -Wredundant-decls to /usr/include/* but does it for all 
other headers and in the case of cross compilation I hit this case.

Does anyone know the way to tell gcc that libc headers are not at 
/usr/include but somewhere else?



[aik@aik ~]$ cp /usr/include/assert.h ./
[aik@aik ~]$
[aik@aik ~]$ cat a.c
#pragma GCC diagnostic error "-Wredundant-decls"

#ifdef USEMINE
#include "assert.h"
#include "assert.h"
#else
#include <assert.h>
#include <assert.h>
#endif

int main(int argc, char **argv){ return 0; }
[aik@aik ~]$
[aik@aik ~]$ gcc a.c -o a
[aik@aik ~]$ gcc a.c -o a -DUSEMINE
In file included from a.c:5:0:
assert.h:68:13: error: redundant redeclaration of ‘__assert_fail’ 
[-Werror=redundant-decls]
In file included from a.c:4:0:
assert.h:68:13: note: previous declaration of ‘__assert_fail’ was here
In file included from a.c:5:0:
assert.h:73:13: error: redundant redeclaration of ‘__assert_perror_fail’ 
[-Werror=redundant-decls]
In file included from a.c:4:0:
assert.h:73:13: note: previous declaration of ‘__assert_perror_fail’ was here
In file included from a.c:5:0:
assert.h:80:13: error: redundant redeclaration of ‘__assert’ 
[-Werror=redundant-decls]
In file included from a.c:4:0:
assert.h:80:13: note: previous declaration of ‘__assert’ was here
cc1: some warnings being treated as errors
[aik@aik ~]$




-- 
Alexey