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Subject:	CLOCKS_PER_SEC of time.h doesn't work to prove it is a value for one second
From:	"K.J.Williams" <lordwilliams1972 AT gmail DOT com>
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I tried a program that I found on the internet which calculates how many CLOCKS_PER_SEC are in one second. I compiled and ran the program on two different computers but got the same result. Then I took a look at time.h and found how CLOCKS_PER_SEC was implemented for DJGPP (I added this as a comment in the code code). I posted this code here because CLOCKS_PER_SEC is implementation defined stated by the ISO C standard. 


The original source code is from : 

http://www.acm.uiuc.edu/webmonkeys/book/c_guide/2.15.html#variables

see "2.15.3 clock"


heres my file: clocks_1.c  

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

/*

a documentation note in DJGPP's time.h file states:

   65536(tics/hour) / 3600(sec/hour) * 5(scale) = 91.02
   The 5 is to make it a whole number (18.2*5=91) so that
   floating point ops aren't required to use it.

#define CLOCKS_PER_SEC 91

*/



int main(void)
{
  clock_t ticks1, ticks2;

  ticks1=clock();
  ticks2=ticks1;
  while((ticks2/CLOCKS_PER_SEC-ticks1/CLOCKS_PER_SEC)<1)
    ticks2=clock();

  printf("Took %ld ticks to wait one second.\n",ticks2-ticks1);
  printf("This value should be the same as CLOCKS_PER_SEC which is %ld.\n",CLOCKS_PER_SEC);
  return 0;
}

(eof)

Output ( binary tested on two different PC computers ):

Took 95 ticks to wait one second.
This value should be the same as CLOCKS_PER_SEC which is 91.

So... 95 ticks is not equal to CLOCKS_PER_SEC. Is the documentation note in 
time.h a using a correct calculation to determine CLOCKS_PER_SEC's value?   

Thanks

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