[current tinderbox] failure on amd64/amd64

[Bruce Evans]

On Thu, 5 May 2005, Bill Paul wrote:

>> On Thu, 5 May 2005, Xin LI wrote:
>>
>>> On Thu, May 05, 2005 at 04:44:28AM -0400, FreeBSD Tinderbox wrote:
>>>> /tinderbox/CURRENT/amd64/amd64/src/sys/modules/ndis/../../compat/ndis/subr_ndis.c: In function `NdisMFreeSharedMemory':
>>>> /tinderbox/CURRENT/amd64/amd64/src/sys/modules/ndis/../../compat/ndis/subr_ndis.c:1710: warning: long long unsigned int format, uint64_t arg (arg 3)
>>>
>>> Maybe we should make use of the PRIx64 macro?  (see patch attached)
>>
>> No.  PRI* is a bug in C99; it should never be used.  Just cast the arg to
>> a suitable larger type with a known format (uintmax_t here).  (C99 is
>> missing support for better ways; either %I as in sfio (?) or %DWIM where
>> the compiler rewrites the string to match the arg would be better.)
>
> I think what you really meant to say was:
>
> "Use %jx instead of %qx."
>
> Am I right?

No, the arg must match the format.  %jx matches uintmax_t, but the arg has
type uint64_t.  uint64_t just happens to be the same as uintmax_t on all
supported machines, so using %jx without casting the arg to match gives a
latent bug.

Bruce