Yes, you're correct. In glibc 2.44, time() uses a macro which is defined
as CLOCK_REALTIME_COARSE.
The definition of gettimeofday(), on the other hand, refers directly to
CLOCK_REALTIME, just as you note.
On 8/19/26 13:43, Ian Collier via Mutt-dev wrote:
On Wed, Aug 19, 2026 at 07:01:59PM +0200, Steffen Nurpmeso wrote:
Musl impl is
#include "syscall.h"
time_t time(time_t *t)
{
struct timespec ts;
__clock_gettime(CLOCK_REALTIME, &ts);
if (t) *t = ts.tv_sec;
return ts.tv_sec;
}
I believe glibc uses CLOCK_REALTIME_COARSE in that syscall (but
CLOCK_REALTIME for the gettimeofday(2) function).
If I understand correctly, CLOCK_REALTIME asks the clock hardware
whereas CLOCK_REALTIME_COARSE fetches a stored value that is updated
once per jiffy.
On modern systems HZ=1000, but my testing showed a delay of up to 1.53ms
on x86_64 and 1.08ms on arm64.
Ian Collier.
