[PATCH] libc: Add/Update prototypes For POSIX Issue 8 functions

[Brian Inglis]

On 2025-06-21 15:34, Mazen Adel Elmessady wrote:
...> diff --git a/newlib/libc/include/time.h b/newlib/libc/include/time.h
> index ab3491341..a2df4f7fd 100644
> --- a/newlib/libc/include/time.h
> +++ b/newlib/libc/include/time.h
> @@ -57,6 +57,11 @@ clock_t	   clock (void);
>   double	   difftime (time_t _time2, time_t _time1);
>   time_t	   mktime (struct tm *_timeptr);
>   time_t	   time (time_t *_timer);
> +#if (__ISO_C_VISIBLE >= 2011 || __POSIX_VISIBLE >= 202405)
> +#define TIME_UTC 1
> +
> +int        timespec_get(struct timespec *ts, int base);
> +#endif
>   #ifndef _REENT_ONLY
>   char	  *asctime (const struct tm *_tblock);
>   char	  *ctime (const time_t *_time);
Shouldn't the time base TIME_... values depend on what is available and used by 
the implementation, environment, or operating system?

For example, Cygwin already defines TIME_UTC in cygwin/time.h.

Time base values such as TIME_UTC, TIME_TAI, TIME_LCL, TIME_ACTIVE, 
TIME_THREAD_ACTIVE, etc. could be valid.

These MUST be defined in the same header where any other TIME_... constants are 
defined, as they MUST NOT have conflicting or overlapping values.

See N3220 ISO/IEC 9899:2024 WD aka <wink> ISO/IEC 9899:2023 FDIS:

7.29.1 Components of time
2 ...
         TIME_UTC
         TIME_MONOTONIC
   which expand to integer constants greater than 0 designating the
   calendar time and monotonic time bases, respectively. Additional time
   base macro definitions, beginning with TIME_ and an uppercase letter,
   may also be specified by the implementation; and,
         TIME_ACTIVE
         TIME_THREAD_ACTIVE
   which, if defined, expand to integer values, designating overall
   execution and thread-specific active processing time bases,
   respectively.
3 The definition of macros for time bases other than TIME_UTC are optional.
   If defined, the corresponding time bases are supported by timespec_get
   and timespec_getres, and their values are positive.
   If defined, the value of the optional macro TIME_ACTIVE shall be
   different from the constants TIME_UTC and TIME_MONOTONIC and shall not
   change during the same program invocation.
   The optional macro TIME_THREAD_ACTIVE shall not be defined if the
   implementation does not support threads; its value shall be different
   from TIME_UTC, TIME_MONOTONIC, and TIME_ACTIVE, it shall be the same
   for all expansions of the macro for the same thread, and the value
   provided for one thread shall not be used by a different thread as the
   base argument of timespec_get or timespec_getres.
...
7.33.18 Date and time <time.h>
1 Macros beginning with TIME_ and an uppercase letter may be added to
   the macros in the <time.h> header by a future revision of this
   document or by an implementation.
2 The time bases TIME_MONOTONIC, TIME_ACTIVE and TIME_THREAD_ACTIVE may
   become mandatory in future versions of this standard.
...

NOTE: w32api-headers w32api/timezoneapi.h TIME_ZONE_... and other TIME_... 
constants and types may conflict with this spec in draft and future releases.

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retrancher  but when there is no more to cut
                                 -- Antoine de Saint-Exupéry