Re: [Qemu-devel] Mingw GCC not recognising printf format "%I64u"

[Anthony Liguori <anthony@codemonkey.ws>]

Jamie Lokier wrote:
> Anthony Liguori wrote:
>   
>>>> #ifdef _WIN32
>>>> #define PRIu64 "%llu"
>>>> #endif
>>>>
>>>>         
>>> Qemu does that already!
>>>       
>> I don't think so.  mingw32 actuallt defines PRIu64 as "%I64u" even 
>> though GCC doesn't like it.
>>     
>
> Look again.  qemu/qemu-common.h:
>
> #ifdef _WIN32
> #define WIN32_LEAN_AND_MEAN
> #define WINVER 0x0501  /* needed for ipv6 bits */
> #include <windows.h>
> ...etc...
> #define PRId64 "I64d"
> #define PRIx64 "I64x"
> #define PRIu64 "I64u"
> #define PRIo64 "I64o"
> #endif
>
> The only condition is whether _WIN32 is defined, which means WIN32
> API, except that it's also defined with Cygwin (and other unix
> emulations) which have quite different functions.
>   

Okay, I wrote a small program that included inttypes.h.  PRIu64 was 
defined as I64u.

>> FWIW, the following seems to work for me:
>>
>> /* Mingw has a broken PRIu64 */
>> #if defined(__MINGW32__)
>> #undef PRIu64
>> #define PRIu64 "Ld"
>> #endif
>>     
>
> (Should by "Lu", btw).
>
> How you checked it prints correctly?  There are Googlable reports of
> people using "%lld" on Mingw saying that it doesn't print large 64-bit
> values correctly, because it truncates them to 32 bits, and trying
> "%I64u" and it works.  Possibly due to Mingw programs calling
> Microsoft's C library, therefore being subject to Windowsness.
>   

I only tried with a small number so it could possibly truncate large 
numbers.

Regards,

Anthony Liguori

> The same _could_ happen with "%Ld" or "%Lu", if Microsoft hasn't
> implemented that as 64-bit.
>
> -- Jamie
>
>
>