Newsgroups: comp.os.msdos.djgpp
Subject: Re: DPMI for Dummies
From: gcheak AT sbinet DOT com (Greg Cheak)
Organization: <Not Organized>
References: <3523cca3 DOT 0 AT newscene> <35256B92 DOT 76B4 AT cs DOT com>
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Date: 4 Apr 1998 13:55:06 +0600
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To: djgpp AT delorie DOT com
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Thanks John and Charles - 

	By dropping out of Win95 and running CWSDPMI I was able to gain more 
memory; alot more. I also added some code to see just exactly how much memory 
the program was asking for in bytes. What I found was that there was no way I 
would get enough resources (perhaps with a Cray). Then I attempted to add some 
DPMI calls to check available memory in the program, which I may have 
incorrectly called. Curious what the proper call would be to report all 
available memory? I used __dpmi_get_memory_information with a call to 
the total_available_bytes_of_virtual_memory_host member. Is this proper?
If I had this value I could exit the program more gracefully. In any case its 
running better now with your help. Thanks.

- Greg


In article <35256B92 DOT 76B4 AT cs DOT com>, fighteer AT cs DOT com says...
>
>What Charles Terry said is entirely correct; I should add that, to see
>how much physical and virtual memory DJGPP programs think is available,
>type "go32-v2" from the DOS prompt.  If the numbers add up to less than
>64 MB, make sure you have the MS-DOS prompt properties sheet configured
>properly in Windows 95.
>
>Please also note that DJGPP malloc() rounds all memory requests up to
>the nearest power of 2, and Windows 95's DPMI host won't let you
>allocate any more than half of the remaining virtual memory in any
>single chunk.  So, calling malloc() with a request greater than or near
>to 32 MB is almost guaranteed to fail even though it looks like you have
>enough available memory.
>
>If you don't like this behavior, run in DOS with cwsdpmi, which lets you
>use up to 256 MB of combined physical and virtual memory (up to 512 MB
>with revision 4).
>
>-- 
>---------------------------------------------------------------------
>|      John M. Aldrich       | "A committee is a life form with six |
>|       aka Fighteer I       | or more legs and no brain."          |
>|   mailto:fighteer AT cs DOT com   |                                      |
>| http://www.cs.com/fighteer |                 - Lazarus Long       |
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