This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: checking changes for warning regressions


On Wed, Oct 10, 2012 at 4:26 PM, Roland McGrath <roland@hack.frob.com> wrote:
>> If it is true, why can't we use uint64_t for bswap_64?
>
> We can if we think it's OK for all the headers using <bits/byteswap.h>
> to include <stdint.h> and put all those symbols into the name space.
> That may well be fine, but it needs careful consideration.
>
> The conservative change is to conditionalize the use of long vs long long
> in bits/byteswap.h--that just fixes the regression, without changing the
> API of any public header.

Glibc 2.16 has

# if __GNUC_PREREQ (4, 2)
static __inline unsigned long long int
__bswap_64 (unsigned long long int __bsx)
{
  return __builtin_bswap64 (__bsx);
}

It works for x32, i686 and x86-64.  We can use long if
__WORDSIZE  == 64.

-- 
H.J.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]