Using mach_absolute_time to get precise/monotonic clock

main.c

#include <inttypes.h>
#include <mach/mach_time.h>
#include <stdio.h>

int main(void) {
    static mach_timebase_info_data_t timebase;
    mach_timebase_info(&timebase);
    uint64_t time = mach_absolute_time();
    printf("mach_absolute_time: %" PRIu64 "\n", time);
    printf("resolution: %f\n", (double)timebase.numer / (double)timebase.denom);
    printf("time in ns: %" PRIu64 "\n", time * timebase.numer / timebase.denom);
    return 0;
}