clocks.c

#include <time.h>
#include <sys/time.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>

// http://c-faq.com/stdio/commaprint.html
#include <locale.h>
char *commaprint(unsigned long n)
{
	static int comma = '\0';
	static char retbuf[30];
	char *p = &retbuf[sizeof(retbuf)-1];
	int i = 0;

	if(comma == '\0') {
		struct lconv *lcp = localeconv();
		if(lcp != NULL) {
			if(lcp->thousands_sep != NULL &&
				*lcp->thousands_sep != '\0')
				comma = *lcp->thousands_sep;
			else	comma = ',';
		}
	}

	*p = '\0';

	do {
		if(i%3 == 0 && i != 0)
			*--p = comma;
		*--p = '0' + n % 10;
		n /= 10;
		i++;
	} while(n != 0);

	return p;
}

// macro to call clock_gettime w/different values for CLOCK
#define do_clock(CLOCK) \
do { \
   struct timespec x; \
   clock_getres(CLOCK, &x); \
   printf("%25s\t%15s", #CLOCK, commaprint(x.tv_nsec)); \
   clock_gettime(CLOCK, &x); \
   printf("\t%15s", commaprint(x.tv_sec)); \
   printf("\t%15s\n", commaprint(x.tv_nsec)); \
} while(0)




int main(int argc, char** argv )
{
   printf("%25s\t%15s\t%15s\t%15s\n", "clock", "res (ns)", "secs", "nsecs");

   struct timeval tv;
   gettimeofday(&tv, NULL);
   printf("%25s\t%15s\t%15s\t", "gettimeofday","1,000", commaprint(tv.tv_sec));
   printf("%15s\n", commaprint(tv.tv_usec*1000));
   
#if _POSIX_TIMERS > 0   

   #ifdef CLOCK_REALTIME
   do_clock(CLOCK_REALTIME);
   #endif

   #ifdef CLOCK_REALTIME_COARSE
   do_clock(CLOCK_REALTIME_COARSE);
   #endif

   #ifdef CLOCK_REALTIME_HR
   do_clock(CLOCK_REALTIME_HR);
   #endif

   #ifdef CLOCK_MONOTONIC
   do_clock(CLOCK_MONOTONIC);
   #endif

   #ifdef CLOCK_MONOTONIC_RAW
   do_clock(CLOCK_MONOTONIC_RAW);
   #endif

   #ifdef CLOCK_MONOTONIC_COARSE
   do_clock(CLOCK_MONOTONIC_COARSE);
   #endif
   
#endif

   return 0;
}