Re: [Xen-devel] [PATCH] printk: prefer %#x et at over 0x%x

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 21.09.12 at 13:40, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> On Fri, 2012-09-21 at 12:28 +0100, Jan Beulich wrote:
>> --- 2012-09-21.orig/xen/arch/x86/apic.c 2012-09-17 09:57:54.000000000 +0200
>> +++ 2012-09-21/xen/arch/x86/apic.c      2012-09-21 10:54:46.000000000 +0200
>> @@ -689,7 +689,7 @@ void __devinit setup_local_APIC(void)
>>          value = apic_read(APIC_ESR);
>>          if (value != oldvalue)
>>              apic_printk(APIC_VERBOSE, "ESR value before enabling "
>> -                        "vector: 0x%08lx  after: 0x%08lx\n",
>> +                        "vector: %#lx  after: %#lx\n",
> 
> This is dropping the 0 padding?
> 
> Perhaps deliberate, I just mention it because of my next comment...

Yes - there's no need for the full width printing here. I did take
care not to replace the format in cases where the zero-padding
would be useful.

>> --- 2012-09-21.orig/xen/arch/x86/cpu/mcheck/vmce.c      2012-08-08 
>> 08:20:09.000000000 +0200
>> +++ 2012-09-21/xen/arch/x86/cpu/mcheck/vmce.c   2012-09-21 
>> 10:54:46.000000000 +0200
>> @@ -88,7 +88,7 @@ static int bank_mce_rdmsr(const struct v
>>      case MSR_IA32_MC0_CTL:
>>          /* stick all 1's to MCi_CTL */
>>          *val = ~0UL;
>> -        mce_printk(MCE_VERBOSE, "MCE: rdmsr MC%u_CTL 0x%"PRIx64"\n",
>> +        mce_printk(MCE_VERBOSE, "MCE: rdmsr MC%u_CTL %#"PRIx64"\n",
> 
> PRIx64 is something like "016llx".

No - it's just "llx" or "lx". Are you perhaps mixing this up with
PRIpaddr?

> Tim pointed out to me that "%#010x" renders the number 0 as 0000000000
> rather than 0x00000000 which was more likely what was desired.
> 
> This is apparently a deliberate "feature" of printf (or at least it is
> standardized)
> 
> Also in the %#"PRIx64" case the width is 016 which is 2 too few once you
> include the 0x.

Indeed, that would be the case if PRIx64 was defined you thought
it would be.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel