Defined in header <time.h>
int timespec_getres( struct timespec *ts, int base );
(since C23)

If ts is non-null and base is supported by timespec_get, modifies *ts to hold the resolution of time provided by timespec_get for base. For each supported base, multiple calls to timespec_getres during the same program execution have identical results.


ts - pointer to an object of type struct timespec
base - TIME_UTC or another nonzero integer value indicating the time base

Return value

The value of base if base is supported, zero otherwise.


The POSIX function clock_getres(clock_id, ts) may also be used to populate a timespec with the resolution of time identified by clock_id.


#include <stdio.h>
#include <time.h>
int main(void)
    char buff[128];
    struct timespec ts;
    const int res = timespec_getres(&ts, TIME_UTC);
    if (res == TIME_UTC) {
        struct tm timer;
        strftime(buff, sizeof buff, "%D %T", gmtime_r(&ts.tv_sec, &timer));
        printf("Time resolution info: %s.%09ld UTC\n", buff, ts.tv_nsec);
    } else {
        printf("TIME_UTC base is not supported.");

Possible output:

Time resolution info: 01/01/70 00:00:00.000000001 UTC

See also

time in seconds and nanoseconds
returns the calendar time in seconds and nanoseconds based on a given time base
returns the current calendar time of the system as time since epoch

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