Re: What is the right way to print a UINTN?

[Andrew Fish <afish@apple.com>]

> On Sep 27, 2016, at 9:03 AM, Cohen, Eugene <eugene@hp.com> wrote:
> 
>> Printing UINTN with %x *or* with %d are equally bugs.
>> 
>> For X64 / AARCH64 / IA64 builds, they are actual bugs (that happen to
>> work most of the time).
> 
> Feel free to file a Bugzilla on the extensive usage of this in edk2 [ducking and running].  :)
> 
>>> I'm envisioning having to create a slide in the future for UEFI
>>> training about the proper use of UINTNs and describing "If you think
>>> it may exceed 2^32-1 then upcast to UINT64, otherwise don't worry
>>> about it" and it makes me squirm.
>> 
>> It makes me squirm too. I think the slide should recommend the
>> casting
>> that I proposed. ;) "There is no conversion specifier dedicated to
>> UINTN; the portable way to print it is to cast it to UINT64, then print
>> it with %Lx."
> 
> This is reasonable although I expect to get asked why a lot of the other code doesn't adhere to this recommendation.
> 

I think this is a historical artifact. The older version of %x in the EDK (and early edk2) implied UINTN. We hit an issue with C integer math resulting in an int and that seemed to bork some toolchains. That is when things changed from UINTN to int. I guess the cleanup was practical vs. pedantic. 

Thanks,

Andrew Fish

> Thanks,
> 
> Eugene
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