Messages in this thread | | | Date | Sun, 08 May 2011 14:12:59 -0500 | From | Greg Dietsche <> | Subject | Re: [PATCH] usb: fix warning in usbtest module |
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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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