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

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 04/15/2013 05:18 PM, Peter Maydell wrote:
> On 15 April 2013 03:31, Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
>> The assert.h header file from Fedora18 does not have #ifdef-#endif
>> brackets around __assertXXXX function so it cannot compile with
>> the -Wredundant-decls switch on.
>>
>> Some Linux distributions (such as Debian Wheezy) still do have those
>> brackets arounb __assertXXXX functions (#ifndef _ASSERT_H_DECLS) but
>> the version of assert.h on http://sourceware.org/git/?p=glibc.git does not
>> so we should not be using -Wredundant-decls.
>>
>> The patch removes it.
>
> This commit message seems to be missing any mention of
> which versions of pixman this change breaks and why
> it's OK now to break compiling against them...


The change does not _break_ anything. By default, it will just generate 
warnings, but only if "-Wredundant-decls" is set.

The second removed chunk in the patch is the problem as it:
1) enables -Wredundant-decls even if it was not enabled before;
2) makes -Wredundant-decls an error, not just a warning.

Default assert.h shipped with Fedora Core 18 (pretty recent and popular 
distribution, I would say) cannot compile with -Wredundant-decls as an 
error so we should either avoid -Wredundant-decls or watch where we include 
assert.h very carefully.



>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> ---
>>   include/ui/qemu-pixman.h |    6 ------
>>   1 file changed, 6 deletions(-)
>>
>> diff --git a/include/ui/qemu-pixman.h b/include/ui/qemu-pixman.h
>> index b032f52..6f473f9 100644
>> --- a/include/ui/qemu-pixman.h
>> +++ b/include/ui/qemu-pixman.h
>> @@ -7,13 +7,7 @@
>>   #define QEMU_PIXMAN_H
>>
>>   /* pixman-0.16.0 headers have a redundant declaration */
>
> ...and if it's a correct change it should be removing the
> comment as well, since it would no longer apply.
>
>> -#ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
>> -#pragma GCC diagnostic ignored "-Wredundant-decls"
>> -#endif
>>   #include <pixman.h>
>> -#ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
>> -#pragma GCC diagnostic error "-Wredundant-decls"
>> -#endif
>>
>>   #include "qemu/typedefs.h"
>>
>> --
>> 1.7.10.4
>
> thanks
> -- PMM
>


-- 
Alexey