From: "AndrewJ" <luminous-is AT home DOT com>
Newsgroups: comp.os.msdos.djgpp
References: <393682e4$0$81880 AT SSP1NO17 DOT highway DOT telekom DOT at>
Subject: Re: DPMI
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Date: Thu, 01 Jun 2000 18:50:44 GMT
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Hi Florian,

> There are some dpmi funktions, which tell me how many memory is free
> (physical and virtual). But how can I know, how much memory has the
> computer? Is there a funktion?

You might try try INT 31h/0500h, dpmi get free memory information.

/* %DJDIR%/include/dpmi.h, line 189 */
int __dpmi_get_free_memory_information(__dpmi_free_mem_info *_info);

If you multiply the value in
__dpmi_free_mem_info.total_number_of_physical_pages by 4096 (the size of a page
in bytes), you should get the total amount of physical memory available (note:
not the total amount of physical memory free).

/* dpmipmem.c - gcc -Wall -o dpmipmem.exe dpmipmem.c */
/* a small example demonstrating how to get the total/free amount of physical
memory */

#include <stdio.h>
#include <dpmi.h>

int main(void)
  {
  __dpmi_free_mem_info info;

/* should probably check the return code, but... */
  __dpmi_get_free_memory_information(&info);

  printf("%ld bytes physical memory (%ld pages)\n",
    info.total_number_of_physical_pages * 4096,
    info.total_number_of_physical_pages);

  printf("%ld bytes total free space (%ld pages)\n",
    info.total_number_of_free_pages * 4096,
    info.total_number_of_free_pages);

  return(0);
  }

This gives me 66273280 and 49610752 respectively, which is right for my 64MB
machine with 49 mb or so of DPMI memory available (set through the
properties/memory page for the DOS window).

AndrewJ