Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!netcom!mojo
From: mojo@netcom.UUCP (Morris Jones)
Newsgroups: comp.windows.ms.programmer
Subject: Re: 32 bit applications under Windows
Message-ID: <18118@netcom.UUCP>
Date: 5 Dec 90 07:37:28 GMT
References: <1990Dec4.221303.16472@nntp-server.caltech.edu>
Distribution: na
Organization: Netcom- The Bay Area's Public Access Unix System {408 241-9760 guest}
Lines: 30

dank@nntp-server.caltech.edu (Daniel R. Kegel) writes:
>I am trying to figure out how to write a Windows program that uses
>much more than 640 kilobytes of memory, and have heard that the
>DOS Extenders built in to Windows3.0 and Desqview have the same API,
>which is defined in something with a name like "Virtual Control Program 
>Interface".  

Windows uses a slightly new spec called DOS Protected Mode Interface (DPMI).

Support for allocating large chunks of memory is provided by the
WINMEM32 library.  I believe it's described  in Appendix E of the SDK
manual.  These functions allow you to allocate 32-bit segments and
allocate 16-bit pointer aliases, code aliases, and so on.

At Caere we used these functions to run OCR in native 32-bit 386 code.
The 32-bit compiler we used was Metaware High C.  The difficulty comes
in provided glue and control transfer code between the 16- and 32-bit
segments.  Codeview will not run with a 32-bit stack, so WDEB386 is
the only debugger useable, and it will not load symbols.

It's a considerable investment to make a 32-bit Windows program, so
read and consider whether or not it's necessary.

Mojo

-- 
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