[PATCH xquartz 04/10] randr: Silence -Wshift-negative-value warnings

[Jeremy Huddleston Sequoia]

> On Oct 14, 2015, at 15:33, Alan Coopersmith <alan.coopersmith at oracle.com> wrote:
> 
> On 10/14/15 03:13 PM, Jeremy Huddleston Sequoia wrote:
>> rrtransform.c:199:23: warning: shifting a negative signed value is undefined [-Wshift-negative-value,Semantic Issue]
>>             rot_cos = F(-1);
> 
> 
>> -            rot_cos = F(-1);
>> +            rot_cos = F(~0u);
> 
> Is -1 guaranteed to be ~0u on all platforms?   Or just all the ones we know
> and care about?


I'm pretty certain that ~0u and -1 are the same bit patterns on all platforms.  I can't think of a reason why they wouldn't be.



> Would it be better to instead do:
> -#define F(x)    IntToxFixed(x)
> +#define F(x)    IntToxFixed((uint32_t) x)
> 
> in randr/rrtransform.c ?
> 
> -- 
> 	-Alan Coopersmith-              alan.coopersmith at oracle.com
> 	 Oracle Solaris Engineering - http://blogs.oracle.com/alanc

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