On Sun, May 08, 2011 at 02:12:59PM -0500, Greg Dietsche wrote: > 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. Sorry, but no, use 'unsigned long' please. In the kernel, it's guaranteed to hold the size of a pointer, that is one of the requirements of Linux. And as for C99, those types don't make any sense in the kernel, only in userspace. See Linus's posts on this a few years back on lkml if you want all of the details. So please redo this patch with 'unsigned long' and I will be glad to queue it up. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
