BOOL WINAPI GlobalMemoryStatusEx(
  __inout  LPMEMORYSTATUSEX lpBuffer
);

//  Sample output:
//  There is       51 percent of memory in use.
//  There are 2029968 total Kbytes of physical memory.
//  There are  987388 free Kbytes of physical memory.
//  There are 3884620 total Kbytes of paging file.
//  There are 2799776 free Kbytes of paging file.
//  There are 2097024 total Kbytes of virtual memory.
//  There are 2084876 free Kbytes of virtual memory.
//  There are       0 free Kbytes of extended memory.

#include <windows.h>
#include <stdio.h>

// Use to convert bytes to KB
#define DIV 1024

// Specify the width of the field in which to print the numbers. 
// The asterisk in the format specifier "%*I64d" takes an integer 
// argument and uses it to pad and right justify the number.
#define WIDTH 7

void main(int argc, char *argv[])
{
  MEMORYSTATUSEX statex;

  statex.dwLength = sizeof (statex);

  GlobalMemoryStatusEx (&statex);

  printf ("There is  %*ld percent of memory in use.\n",
          WIDTH, statex.dwMemoryLoad);
  printf ("There are %*I64d total Kbytes of physical memory.\n",
          WIDTH, statex.ullTotalPhys/DIV);
  printf ("There are %*I64d free Kbytes of physical memory.\n",
          WIDTH, statex.ullAvailPhys/DIV);
  printf ("There are %*I64d total Kbytes of paging file.\n",
          WIDTH, statex.ullTotalPageFile/DIV);
  printf ("There are %*I64d free Kbytes of paging file.\n",
          WIDTH, statex.ullAvailPageFile/DIV);
  printf ("There are %*I64d total Kbytes of virtual memory.\n",
          WIDTH, statex.ullTotalVirtual/DIV);
  printf ("There are %*I64d free Kbytes of virtual memory.\n",
          WIDTH, statex.ullAvailVirtual/DIV);

  // Show the amount of extended memory available.

  printf ("There are %*I64d free Kbytes of extended memory.\n",
          WIDTH, statex.ullAvailExtendedVirtual/DIV);
}