From: egmose AT image DOT dk (Søren Egmose)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: How to determine the physical address from a DPMI descriptor
Date: Mon, 24 Aug 1998 11:26:44 GMT
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References: <Pine DOT SUN DOT 3 DOT 91 DOT 980823162729 DOT 1451D-100000 AT is> <35e04c8f DOT 1705102 AT news DOT teaser DOT fr>
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In artikel <35e04c8f DOT 1705102 AT news DOT teaser DOT fr>,
On Sun, 23 Aug 1998 18:10:52 GMT, jpdelprat AT teaser DOT fr (JP) wrote:

>Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> wrote:
>
>>
>>On Tue, 18 Aug 1998, JP wrote:
>>
>>> My need is to create and lock a 2Mo continuous buffer (under Windows
>>> 95), and determine its physical address to give it to a video capture card.
>>
>>I think section 18.7 of the FAQ should get you started.
>>
>>> With DPMI functions (under Windows 95), I allocate my buffer then 
>>> lock it, but despite the call to dpmi_lock_linear_region, the buffer
>>> is still mixed and partially swapped out.
>>
>>Did you remember to make your segment to have a size that's a multiple of 
>>4KB?
>
>Thanks for the advice. I hadn't noticed this point. Fortunately, my
>buffer is exactly 2M. So it should be ok. 
>
>I have found another solution : I allocate and lock an xms buffer
>before Windows starts. This buffer is continuous and cannot be used by
>Windows. The drawback is that my system now has less memory. I would
>prefer to allocate my buffer when I run my program, but I could find
>any way.

Under windows you would use something like the following to get a
non-swappable array.

mem = GlobalAlloc(GMEM_FIXED, TWOMB);

isn't there anything like this in djgpp?
-- 
mvh.
Søren

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