/*********************************************************************************************/
//System Variables unistd.h man end(3)
/*********************************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>

/*********************************************************************************************/
//Global Constants
/*********************************************************************************************/

#define SHOW_ADDRESS(ID, I) printf("The id %s \t is at:%8X\n", ID, (unsigned long int)&I);


/*********************************************************************************************/
//System Variables unistd.h man end(3)
/*********************************************************************************************/

extern int etext, edata, end ;


char *Ptr = "String C \n " ;   // initialized global
char  Buff[100] ;               // uninitialized global


/*********************************************************************************************/
// Function prototype -- PtrFct=function pointer
/*********************************************************************************************/

void PtrFct( int LocUninit ) {
  int LocInit = 1;

  SHOW_ADDRESS(" LocUninit (inside PtrFct) " , LocUninit )
  if(LocUninit > 0) {
    PtrFct(LocUninit-LocInit);
  }
}

/*********************************************************************************************/
//Main
/*********************************************************************************************/

int main( int argc, char *argv[ ], char *envp [ ] )
{
 int i = 0;            // local intialized => stack segment
 static int diff;      // static local uninitialized =>data segment
 static int StackCalls = 5; // static local intialized => data segment

 int * IntPtr1 = (int *)malloc(10 * sizeof(int)); //heap
 int * IntPtr2 = (int *)malloc(10 * sizeof(int)); //heap


strcpy (Buff, " Layout of virtual memory \n ");

write(1, Buff, strlen(Buff)+1) ;
printf("Adr etext : %8X \t Adr edata : %8X \t Adr end : %8X \n\n" ,
       ( unsigned long int )&etext, ( unsigned long int ) &edata, (
unsigned long int ) &end );

printf (" Variable \t HEX_ADDR " ) ;

SHOW_ADDRESS(" main " , main ) ;
SHOW_ADDRESS(" PtrFct ", PtrFct) ;
SHOW_ADDRESS(" etext " , etext ) ;
diff = ( unsigned long int ) &PtrFct - ( unsigned long int ) &main;
printf(" PtrFct is  %d bytes above main\n", diff );


SHOW_ADDRESS(" Global Ptr ", Ptr ) ;
diff = ( unsigned long int ) &Ptr - ( unsigned long int ) &PtrFct;
printf(" Ptr is %d bytes above PtrFct \n" , diff ) ;

SHOW_ADDRESS(" Global Buff" , Buff) ;
printf(" IntPtr1 %8X\n" ,  ( unsigned long int )IntPtr1) ;
printf(" IntPtr2 %8X\n" , ( unsigned long int )IntPtr2) ;
SHOW_ADDRESS(" diff " , diff ) ;
SHOW_ADDRESS(" stack calls" , StackCalls ) ;
SHOW_ADDRESS(" edata " , edata ) ;
SHOW_ADDRESS(" end " , end ) ;
SHOW_ADDRESS(" argc " , argc ) ;
SHOW_ADDRESS(" argv " , argv ) ;
SHOW_ADDRESS(" i " , i ) ;
PtrFct ( StackCalls ) ;
return 0 ;
}