This is the mail archive of the
mailing list for the glibc project.
Re: [PATCH v2 04/11] Use clock_settime to implement settimeofday.
25.10.2019 14:08 Adhemerval Zanella <firstname.lastname@example.org> wrote:
> From: Zack Weinberg <email@example.com>
> Use clock_settime to implement settimeofday.
> Changes from previous version:
> - Added a NEWS entry.
> diff --git a/NEWS b/NEWS
> index 8727b5e7f0..0b1476e745 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -34,6 +34,30 @@ Deprecated and removed features, and other changes
> affecting compatibility:
> binaries and it has been removed from <time.h> header. This function
> has been deprecated in favor of clock_settime.
> +* The settimeofday function can still be used to set a system-wide time
> + zone when the operating system supports it. This is because the Linux
> + kernel reused the API, on some architectures, to describe a system-wide
> + time-zone-like offset between the software clock maintained by the
> + and the “RTC” clock that keeps time when the system is shut down.
That's little off-topic and little nit-picky but are you sure you want to
use the Unicode quotes like “” instead of plain ASCII "" ? No problem if
this is what you really want but I suspect your editor converted this.
> + However, to reduce the odds of this offset being set by accident,
> + settimeofday can no longer be used to set the time and the offset
> + simultaneously. If both of its two arguments are non-null, the call
> + will fail (setting errno to EINVAL).
> + Callers attempting to set this offset should also be prepared for the
> + to fail and set errno to ENOSYS; this already happens on the Hurd and
> + some Linux architectures. The Linux kernel maintainers are discussing
> + more principled replacement for the reused API. After a replacement
> + becomes available, we will change settimeofday to fail with ENOSYS on
> + platforms when its ‘tzp’ argument is not a null pointer.
Same here, the Unicode ‘’ instead of plain ASCII '' .
> + Note that settimeofday itself is obsolescent according to POSIX.
> + Programs that set the system time should use clock_settime and/or
> + the adjtime family of functions instead. We may also cease to make
> + settimeofday available to newly linked binaries after there is a
> + replacement for Linux’s time-zone-like offset API.
Again the Unicode apostrophe ’ instead of plain ASCII ' .