timer.c

#include <stdio.h>
#include <time.h>
#include <stdint.h>
#include <inttypes.h>

double csecond(void) {

    struct timespec tms;

    if (clock_gettime(CLOCK_REALTIME,&tms)) {
        return (0.0);
    }
    /* seconds, multiplied with 1 million */
    int64_t micros = tms.tv_sec * 1000000;
    /* Add full microseconds */
    micros += tms.tv_nsec/1000;
    /* round up if necessary */
    if (tms.tv_nsec % 1000 >= 500) {
        ++micros;
    }
    return( (double) micros /1000000.0) ;
}