#include <locale.h>
#include <assert.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

static double
uptime()
{
   char * savelocale;
   char buf[2048];
   FILE* file;
   if (!(file=fopen( "/proc/uptime", "r"))) {
      fprintf(stderr, "error opening uptime file\n");	
      exit(1);
   }
   savelocale = setlocale(LC_NUMERIC, NULL);
   setlocale(LC_NUMERIC,"C");
   fscanf(file, "%s", buf);
   fclose(file);
   printf("Uptime: %s\n", buf);
   setlocale(LC_NUMERIC,savelocale);
   return atof(buf);
}

/* process age from jiffies to seconds via uptime */
static double process_age(const unsigned jf)
{
   double sc_clk_tck = sysconf(_SC_CLK_TCK);
   printf("SC_CLK_TCK: %f\n", sc_clk_tck);
   assert(sc_clk_tck > 0);
   return uptime() - jf / sc_clk_tck;
}

int main(int argc, char *argv[])
{
	unsigned int proc_stt_jf = 0;
  
	int okay = fscanf(stdin, "%*d %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %ull", 
		       &proc_stt_jf);
	
	if(okay != 1) printf("Bad input\n");
		       
	printf("proc_stt_jf: %u\n", proc_stt_jf);
	printf("Process age: %f\n", process_age(proc_stt_jf));
	
	return 0;
}