Re: [Qemu-devel] [Qemu-trivial] [PATCH] fix MinGW compilation when --enable-vnc-jpeg is specified

[TeLeMan <geleman@gmail.com>]

This patch breaks the compilation with --enable-vnc-png:

  CC    ui/vnc-enc-tight.o
In file included from /usr/include/png.h:518,
                 from ui/vnc-enc-tight.c:34:
/usr/include/pngconf.h:371: error: expected '=', ',', ';', 'asm' or
'__attribute__' before '.' token
/usr/include/pngconf.h:372: error: expected '=', ',', ';', 'asm' or
'__attribute__' before 'include'
make: *** [ui/vnc-enc-tight.o] Error 1

--
SUN OF A BEACH



On Mon, Jun 27, 2011 at 04:26, Blue Swirl <blauwirbel@gmail.com> wrote:
> On Sun, Jun 26, 2011 at 11:03 PM, Stefan Weil <weil@mail.berlios.de> wrote:
>> Am 26.06.2011 20:06, schrieb Blue Swirl:
>>>
>>> On Thu, Jun 23, 2011 at 6:05 PM, Stefan Weil<weil@mail.berlios.de>  wrote:
>>>>
>>>> Am 23.06.2011 15:52, schrieb Stefan Hajnoczi:
>>>>>
>>>>> On Sat, Jun 18, 2011 at 10:35:57AM +0200, Stefan Weil wrote:
>>>>>>
>>>>>> Am 18.06.2011 07:13, schrieb Roy Tam:
>>>>>>>
>>>>>>> This patch fix conflicting types for 'INT32' in basetsd.h in including
>>>>>>> qemu-common.h first.
>>>>>>>
>>>>>>>
>>>>>>> Sign-off-by: Roy Tam<roytam@gmail.com>
>>>>>>> --
>>
>> ...
>>>>>>
>>>>>> The conflicting declaration is in jmorecfg.h which is included from
>>>>>> jpeglib.h.
>>>>>
>>>>> Is the problem that the Windows headers included from qemu-common.h try
>>>>> to #define INT32?
>>>>> http://msdn.microsoft.com/en-us/library/aa383751(v=vs.85).aspx
>>>>>
>>>>> In that case I think an explicit fix is better:
>>>>>
>>>>> #ifdef _WIN32
>>>>> /* Include this before jpeglib.h for the INT32 definition */
>>>>> #include<basetsd.h>
>>>>> #endif
>>>>>
>>>>> ...followed by png/jpeg includes...
>>>>>
>>>>> Simply moving qemu-common.h provides no hints and is rather indirect.
>>>>> Someone may move it back in the future.
>>>>>
>>>>> Stefan
>>>>
>>>> INT32 is declared in basetsd.h which is included from windows.h
>>>> (with some indirections) which is included from qemu-os-win32.h
>>>> which is included from qemu-common.h.
>>>>
>>>> INT32 is not a #define, but a data type (typedef) and very common
>>>> for w32 compilations. Windows programmers don't include basetsd.h
>>>> directly, but usually use windows.h.
>>>>
>>>> Including qemu-common.h right at the beginning (after config.h where
>>>> needed) should be good practice for QEMU source code - like this:
>>>>
>>>> #include "config.h"        /* optional */
>>>> #include "qemu-common.h"
>>>> #include <system includes> /* without those that are included from
>>>> qemu-common.h */
>>>> ...
>>>> #include "other local includes"
>>>> ...
>>>>
>>>> As long as the maintainers don't accept patches which simply move
>>>> qemu-common.h, there is no danger. :-)
>>>>
>>>> Of course a comment might be added. In most cases, I'm a great friend
>>>> of good comments, but in this special case, I don't think it is
>>>> necessary.
>>>> It's a very special case of a typedef conflict caused by the mingw32
>>>> version of jpeglib (which is obviously rarely used), and it might be
>>>> fixed
>>>> in a newer version of jpeglib (so the comment would be no longer
>>>> valid, and nobody would notice that).
>>>
>>> We could also add a configure time check for this case for maximum
>>> over engineering.
>>
>> ... which nobody wants. I suggest to apply the patch as it was sent
>> by Roy. Stefan H. suggests to add a comment before the patch is applied.
>>
>> Both ways fix a (small) problem, so please just decide which
>> solution you prefer.
>
> I applied the patch with a comment, thanks.
>
>