On Sun, Nov 30, 2025, at 11:58, Willy Tarreau wrote:
> On Sat, Nov 22, 2025 at 05:59:15PM +0100, Thomas Weißschuh wrote:
>> struct timespec {
>> - __kernel_old_time_t tv_sec;
>> - long tv_nsec;
>> + time_t tv_sec;
>> + int64_t tv_nsec;
>> };
>> #define _STRUCT_TIMESPEC
>>
>> +/* Never use with system calls */
>> struct timeval {
>> - __kernel_old_time_t tv_sec;
>> - __kernel_suseconds_t tv_usec;
>> + time_t tv_sec;
>> + int64_t tv_usec;
>> };
>
> It seems to me that glibc continues to make the effort of using a long
> for tv_usec and tv_nsec. At least I'm seeing how that can make a
> difference for application code given that these fields are constantly
> multiplied or divided, forcing them to 64-bit when we know they'll never
> be larger than 1 billion is extra burden for the application. Another
> reason might be that the definition really changed from long to suseconds_t
> in timeval a while ago, it's possible that it's used as a long in various
> APIs (or even just printf formats).
>
> IMHO it would be cleaner to keep it as a long here, or do you have a
> particular reason for wanting int64_t (which BTW already forced a cast
> in sys_gettimeofday()) ?
As far as I can tell, it's the other way round for suseconds_t,
which in glibc is defined as
#if __TIMESIZE == 64 && __WORDSIZE == 32
# define __TIME_T_TYPE __SQUAD_TYPE
# define __SUSECONDS_T_TYPE __SQUAD_TYPE
#else
# define __TIME_T_TYPE __SLONGWORD_TYPE
# define __SUSECONDS_T_TYPE __SLONGWORD_TYPE
#endif
so this one is explicitly the same width as tv_sec, which has all
the issues you listed, but avoids the need for padding.
As far as I remember, the one reason for having a 'long tv_nsec'
with complex padding in glibc and musl is that this is actually
required by both Unix[1] and C11/C11 [2] standards.
C23 has updated the definition and does allow int64_t tv_nsec.
I think it makes sense for nolibc to just follow the kernel's
definition here.
Arnd
[1] https://pubs.opengroup.org/onlinepubs/009695399/basedefs/time.h.html
[2] https://en.cppreference.com/w/c/chrono/timespec.html
