Re: [Qemu-devel] [PATCH v2] es1370: Fix compiler warnings for debug code

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

Am 01.10.2010 20:22, schrieb Markus Armbruster:
> Stefan Weil <weil@mail.berlios.de> writes:
>> The patch fixes these gcc warnings:
>>
>> ./hw/es1370.c: In function ‘es1370_update_voices’:
>> ./hw/es1370.c:411: error: format ‘%d’ expects type ‘int’, but 
>> argument 3 has type ‘size_t’
>> ./hw/es1370.c: In function ‘es1370_writel’:
>> ./hw/es1370.c:579: error: format ‘%d’ expects type ‘int’, but 
>> argument 3 has type ‘long int’
>> ./hw/es1370.c:589: error: format ‘%d’ expects type ‘int’, but 
>> argument 3 has type ‘long int’
>> ./hw/es1370.c:606: error: format ‘%d’ expects type ‘int’, but 
>> argument 3 has type ‘long int’
>> ./hw/es1370.c: In function ‘es1370_readl’:
>> ./hw/es1370.c:748: error: suggest braces around empty body in an ‘if’ 
>> statement
>>
>> v2
>>
>> * Use %zd for pointer differences (ptrdiff_t or ssize_t).
>> The gcc error message ("long int") was misleading.
>> Malc, thank you for this hint.
>
> The correct length modifier for ptrdiff_t is 't', not 'z'.
> ISO/IEC 9899:1999 7.19.6.1:
>
> z Specifies that a following d, i, o, u, x, or X
> conversion specifier applies to a size_t or the
> corresponding signed integer type argument; or
> that a following n conversion specifier applies
> to a pointer to a signed integer type
> corresponding to size_t argument.
>
> t Specifies that a following d, i, o, u, x, or X
> conversion specifier applies to a ptrdiff_t or
> the corresponding unsigned integer type
> argument; or that a following n conversion
> specifier applies to a pointer to a ptrdiff_t
> argument.
>
> Not that it makes a difference in practice.


It's always good to learn more. I must admit that I never
used %td before, but it exists, it is obviously supported,
so it should be used.

Therefore I'll send a third version of my patch, and also
patches which fix the other locations in qemu which use
%zd instead of %td for ptrdiff_t.

Thanks,
Stefan