gistfile1.txt

#include <math.h>
#include <time.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

//
//  returns random number from zero to max.
//  to compile this, run the following command.
//  $ gcc -Wall -lm -lrt filename
//
double getRand(int max)
{
    struct drand48_data data;
    struct timespec time;
    double rand = 0;

    int result = clock_gettime(CLOCK_REALTIME, &time);
    if (result == -1) {
        perror("clock_gettime");
        return -1;
    }

    srand48_r(time.tv_nsec, &data);

    drand48_r(&data, &rand);
    rand = floor(rand * max);
    return rand;
}

int main(int argc, char *argv[])
{
    int c;
    for (c = 0; c < 100; c++) {
        printf("%.0f\n", getRand(500)); 
    }
    return 0;
}