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From: fs-info@sbsvax.UUCP (Fachschaft Mathe/Info)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Environment Size
Summary: yet another ideaa
Keywords: environment config shell
Message-ID: <721@sbsvax.UUCP>
Date: 14 Apr 89 13:45:05 GMT
References: <9195@watcgl.waterloo.edu> <11966@paris.ics.uci.edu>
Distribution: comp
Organization: Universitaet des Saarlandes, Saarbruecken, W-Germany
Lines: 43

In article <11966@paris.ics.uci.edu>, asickels@bonnie.ics.uci.edu (Alan Sickels) writes:
> [...]
>    SHELL = C:\COMMAND.COM /E:xxxx /P
> [...]
> BTW this info sould be documented (read it's in the
> manual if you have it).
> Alan Sickels
Well, there are manuals and manuals :-)
Ignoring this one (works fine, but the original question was how to change
the environment size of the currently running COMMAND.COM), I got a small
idea. Can't  prove it but i'll tell you :

The Environment is accessed (as far as I know) through a pointer in a
program's PSP. Now assume that the current process, called by COMMAND.COM,
may get it's fathers PSP (think this my be a DOS call). Then it could
determine the old size of the parent's environment, allocate a new environ-
met through DOS, copy the parent's to this new (and bigger) one, setting
the pointers and sizes of the prents PSP according to the new Block
and, this comes to my mind now, changing the OWNER of the newly allocated
environment to it's parent (else, the block will be deallocated when the
size-changer finishes ) (this mut be done by hangling (is this correct
english?) through DOS's memory-chain.
The process MUST do all this heavy stuff with it's parents PSP because the
own environment is a COPY of the parent's at another memory location.
BTW, as far as I know theonly support from MS-DOS U can get are the few
calls mentioned above.
Hope this was helpful, I unfortunately have no time this decade to try it
on my own, but if you get it fixed, please send me the sources.

Greetings from Germany
  Brian o'Fish

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