#include <unistd.h>
#include <sys/mman.h>
  
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
int main(){
  int k;
   unsigned int m,p;
   const int mem=800000000;
   int len;
   double **dptr;

   m=sizeof(double)+sizeof(double*);
   len=mem/m;
printf("Will allocate %d bytes in %d blocks\n", mem, len);
   dptr = (double **) malloc(sizeof(double*)*len) ;
   for(k=0; k<len; k++) {
     dptr[k] = (double *) mmap(NULL, 500*sizeof(double), PROT_READ|PROT_WRITE, (MAP_PRIVATE|MAP_ANONYMOUS), -1, 0);
     if(dptr[k]==MAP_FAILED) {
	printf("Allocation error: %s\n", strerror(errno));
       printf("k: %d\n",k);
       printf("Alloc Null\n");
getchar();
       exit(-1);
     }
     *(dptr[k]) = rand();
   }
   for(k=len-1; k>=0; k--) {
     printf("value: %d",*(dptr[k]));
   }
   fprintf(stderr,"k=%d mem=%d MB\n",k,mem/1000000);
   exit (0);
 }