Re: [PATCH] usb: fix warning in usbtest module

[Greg Dietsche]

On 05/08/2011 09:37 AM, Alan Stern wrote:
> On Sat, 7 May 2011, Greg Dietsche wrote:
>
>    
> > On amd64 unsigned is not as wide as pointer and this causes
> > a compiler warning. Switching to uintptr_t fixes the problem
> > in an arch independent manner.
> >      
> People tend to prefer to see non-typedef'ed type names, whenever
> possible.  In this case, it would be enough to change the type to
> unsigned long.
>
> Lots of code throughout the kernel stores pointer values in unsigned
> long variables.  I've never heard any recommendation for using
> uintptr_t instead.
>
>    
I was leaning towards unsigned long at first too, but a several things 
made me reconsider:
1) uintptr_t adapts correctly to the size of a pointer on all 
architectures per C99
2) I greped the kernel source and found a number of instances where 
uintptr_t is used
3) unsigned long is technically too wide (though this is better than too 
small...) for some architectures

If the general consensus is that unsigned long is a better choice for 
the kernel, I will update my patch. I do, however think that uintptr_t 
is the best choice from a technical perspective and prefer it over 
unsigned long.

Thanks,
Greg

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