#include <sys/mman.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

static int   PAGESIZE;
static char  file_name[]    = "fooXXXXXX";
static void* global_pointer = NULL;
static int   global_len     = 0;
static int   file_desc      = 0;

int main(int argc, char **argv)
{
    int             i;
    int             result;
    char*           buf;
    unsigned char   vect[20] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
    

    PAGESIZE = getpagesize();
    
    /* global_pointer will point to a mmapped area of global_len bytes */
    global_len = PAGESIZE*2;
    
    buf = (char*)malloc(global_len);
    memset(buf, 42, global_len);  // Asterisks 
    
    /* create a temporary file */
    file_desc = mkstemp(file_name);
    
    /* fill the temporary file with two pages of data */
    write(file_desc, buf, global_len);
    free(buf);
    
    // Will work properly as long as print is before mmap function.
    if ( argc > 1 ) printf("argc=%d\n", argc);

    /* map the file in memory */
    global_pointer = mmap( NULL, global_len,
            PROT_READ|PROT_WRITE|PROT_EXEC, MAP_SHARED, file_desc, 0);

    // Result should be -1 as the request is 5 times actual mapping
    result = mincore(global_pointer, (size_t)(global_len*5), vect);

    // Print some data
    printf("PAGESIZE=%d\n", PAGESIZE);
    printf("global_len=%d\n", global_len);
    printf("global_pointer=0x%x\n", (unsigned int)global_pointer);
    printf("alloc=%d\n", (global_len+PAGESIZE-1) / PAGESIZE );
    printf("Result=%d\n", result);
    printf("vect: ");

    for ( i=0; i<20; i++) printf("%02x ", vect[i]);
    printf("\n");
    
    // Clean up
    munmap(global_pointer, (size_t)global_len);
    close(file_desc);
    unlink(file_name);
}