You need to wait, generating the image take some time (it takes about 90 sec. on Core2 Duo 1.86 GHz). You can also change the resolution in the code to make it faster (by default it is 2560 x 1440).

/*
compile this little piece of code with the command:
 gcc -lrt -Wall -o timertest timertest.c
*/

#include <stdio.h>
#include <stdlib.h> // for floating point output
#include <stdint.h> // for uintXX_t declarations
#include <math.h>
#include <time.h> // let's use HRT
#include <unistd.h> // for - usleep
#include <linux/unistd.h> // for - usleep
#include <sys/time.h> // let's use HRT

#define NSEC_PER_SEC       1000000000
#define TIMER_RELTIME     0

static inline long calcdiff_long(struct timespec t1, struct timespec t2)
{
 long diff;
  diff = NSEC_PER_SEC * ((long) t1.tv_sec - (long) t2.tv_sec);
        diff += ((long) t1.tv_nsec - (long) t2.tv_nsec);
    return diff;
}

static inline double_t calcdiff_double(struct timespec t1, struct timespec t2)
{
      double_t diff;
      diff = (t1.tv_sec - t2.tv_sec);
     diff += ((double_t)(t1.tv_nsec - t2.tv_nsec)) / ((double_t)NSEC_PER_SEC);
   return diff;
}

static inline int addtime(struct timespec tin, uint64_t delta, struct timespec *tout)
{
       uint64_t ldelta;
    ldelta=(uint64_t)delta+(uint64_t)tin.tv_nsec;
       tout->tv_nsec=(uint64_t)ldelta % (uint64_t)NSEC_PER_SEC;
 ldelta-=tout->tv_nsec;
   if (ldelta>0){
              tout->tv_sec=(uint64_t)tin.tv_sec+(uint64_t)ldelta/(uint64_t)NSEC_PER_SEC;
       } else {
                  tout->tv_sec=(uint64_t)tin.tv_sec;
                       }
return 0;
}

int main(int argc, char *argv[]) 
{ 
struct timespec past, now, future,zerotime={0,0};
int ret;
double delay;
uint64_t udelay,ndelay;

delay=0.1;
ndelay=delay*(uint64_t)NSEC_PER_SEC;
udelay=ndelay/1000;

ret=clock_getres(CLOCK_MONOTONIC,&now); // or CLOCK_REALTIME
printf("Timer resolution: %lu ns\n",now.tv_nsec);

/* Get current time */
clock_gettime(CLOCK_MONOTONIC, &past);
usleep(udelay);
/* Get current time */
clock_gettime(CLOCK_MONOTONIC, &now);
printf("usleep(+%.9f s) took: %.9f seconds\n", delay, calcdiff_double(now,past));

clock_gettime(CLOCK_MONOTONIC, &past);
addtime(zerotime, ndelay, &future);
// relative time wait, monolitic is preferred
clock_nanosleep(CLOCK_MONOTONIC, TIMER_RELTIME, &future, NULL);
clock_gettime(CLOCK_MONOTONIC, &now);
printf("relative nanosleep(+%.9f s) took: %.9f seconds\n", delay, calcdiff_double(now,past));

clock_gettime(CLOCK_MONOTONIC, &past);
addtime(past, ndelay, &future);
// absolute time wait
clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &future, NULL);
clock_gettime(CLOCK_MONOTONIC, &now);
printf("absolute nanosleep(+%.9f s) took: %.9f seconds\n", delay, calcdiff_double(now,past));

 return 0; 
} 

    

Nice! Took about 29s in an Ubuntu VM on a hexacore i7. This is single threaded though, right?

error with :
./qjulia
bash: ./qjulia: cannot execute binary file
also
ll qjulia
-rwxr-xr-x. .... qjulia
I have a AMD Athlon XP ...
Very nice to code for mmx ... I need more docs about this .
Thank you. Regards .

catafest wrote:

error with :
./qjulia
bash: ./qjulia: cannot execute binary file
also
ll qjulia
-rwxr-xr-x. .... qjulia
I have a AMD Athlon XP ...
Very nice to code for mmx ... I need more docs about this .
Thank you. Regards .

Hi. Program requires 64 bit processor with SSE 3 support.

$ time ./qjulia -v

real    0m32.919s
user    0m32.648s
sys     0m0.065s