#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <err.h>
#include <sys/times.h>
#include "../lpi.h"

static void
displayProcessTimes(const char *msg)
{
    struct tms t;
    clock_t clockTime;
    static long clockTicks = 0;

    if (msg != NULL)
        printf("%s", msg);

    if (clockTicks == 0) {
        clockTicks = sysconf(_SC_CLK_TCK);
        if (clockTicks == -1)
            err(EXIT_FAILURE, "syscon");
    }

    clockTime = clock();
    if (clockTime == -1)
        err(EXIT_FAILURE, "clock");

    printf("    clock() returns: %ld clocks-per-second (%.3f secs)\n",
            (long) clockTime, (double) clockTime / CLOCKS_PER_SEC);

    if (times(&t) == -1)
        err(EXIT_FAILURE, "times");

    printf("    times() yields: user CPU=%.4f, system CPU=%.4f\n",
            (double) t.tms_utime / clockTicks,
            (double) t.tms_stime / clockTicks);
}

int
main(int argc, char *argv[])
{
    int numCalls, j;

    printf("CLOCKS_PER_SEC=%ld sysconf(_SC_CLK_TCK)=%ld\n\n",
            (long) CLOCKS_PER_SEC, sysconf(_SC_CLK_TCK));

    displayProcessTimes("At program start:\n");

    numCalls = 10000000;
    if (argc > 1)
        toInt(argv[1], &numCalls);
    for (j = 0; j < numCalls; j++)
        (void) getppid();

    displayProcessTimes("After getppid() loop:\n");

    exit(EXIT_SUCCESS);
}