#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void)
{
    unsigned long long required = 33394270208; // 32GB
    char *mem = NULL; 
    while (1) {
        printf ("Required %llu\n", required);
        mem = malloc (required);
        if (mem != NULL)
            break;
        required -= 1024 * 1024;
    }
    printf ("Memory size allocated = %llu\n", required);
    memset(mem, 0, required);
    getchar();
    free (mem);
    return 0;
}