[Qemu-devel] Re: [PATCH] mingw32: Fix definitions for PRId64, PRIx64, PRIu64, PRIo64

[Stefan Weil <weil@mail.berlios.de>]

Am 30.01.2011 23:14, schrieb Blue Swirl:
> On Sun, Jan 30, 2011 at 9:50 PM, Stefan Weil <weil@mail.berlios.de> wrote:
>> Am 30.01.2011 22:39, schrieb Blue Swirl:
>>> It would appear to suppress quite a few warnings about formats. But on
>>> my version of inttypes.h there is the following comment:
>>> /* 7.8.1 Macros for format specifiers
>>> *
>>> * MS runtime does not yet understand C9x standard "ll"
>>> * length specifier. It appears to treat "ll" as "l".
>>> * The non-standard I64 length specifier causes warning in GCC,
>>> * but understood by MS runtime functions.
>>> */
>>> So is this change OK after all?
>>
>> Yes, it is. MS runtime indeed does not understand "%lld"
>> and similar format specifiers.
>>
>> Mingw does, because it replaces the printf family functions
>> by inline functions which call __mingw_vfprintf as soon
>> as __USE_MINGW_ANSI_STDIO is defined. If your MinGW stdio.h
>> does not use __USE_MINGW_ANSI_STDIO, it is too old.
>
> Well, mine doesn't. The change was introduced in mingw-runtime 3.15,
> which was released in September 2008, but Debian still hasn't updated
> from 3.13. Maybe other distros are not so lagging and someone who
> wishes to build QEMU on Windows is not pampered with distro support
> for MinGW anyway. Perhaps a configure time check should be added?
>> QEMU defines __USE_MINGW_ANSI_STDIO, and __mingw_vfprintf
>> understands C9x standard length specifiers.
>
> BTW, MinGW FAQ page http://www.mingw.org/wiki/FAQ still mentions that
> %ll formats are not supported.

The FAQ says
"You should use %I64 instead of %ll when using msvcrt".

=> If you don't use msvcrt for printf, you no longer have to use %I64.

Even with latest versions, MinGW's support for ANSI stdio is still
incomplete - inttypes.h is one example, others are missing
GCC atributes and missing ANSI scanf support.

I'll add a page to QEMU's wiki which lists all changes needed.

Regards,
Stefan