Path: utzoo!utgpu!water!watmath!clyde!rutgers!sunybcs!bingvaxu!leah!emb978
From: emb978@leah.Albany.Edu ( Eric M. Boehm)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Environment space size?
Summary: Setting environment size in DOS 3.x
Keywords: environment variables size
Message-ID: <554@leah.Albany.Edu>
Date: 6 Jan 88 23:45:47 GMT
References: <1900@ukecc.engr.uky.edu>
Distribution: na
Organization: The University at Albany, Computer Services Center
Lines: 36

In article <1900@ukecc.engr.uky.edu>, agollum@engr.uky.edu (David Herron aka Admiral Gollum) writes:
> Maybe I'm being dense, but how does one determine the size of the
> environmment space (ie, how much room there is for environment
> variables) from within a program?  I can read the environment just
> fine, I just don't know how much free space there is.
> 

Assuming you are running MS-DOS 3.2, the default environment space is (I
believe) 256 bytes.

You can change this by inserting the following line into your config.sys
file:

shell=c:\dos\command.com c:\dos /e:nnnn /p

where C:\dos\command.com tells DOS where to load command.com from the
*FIRST* time it is loaded, c:\dos tells dos the pathname to load subsequent
copies of command.com (in case that area of memory is overwritten by your
application program), /e:nnnn tells DOS how many bytes to reserve for
environment space (in 3.1 this number is in paragraphs [16 bytes] so just
divide by 16), and /p tells DOS that this is the primary processor for the
exit command (usually to get out of child processes).

I don't believe this works below 3.x (I have had conflicting reports) but it
does work in 3.1 and 3.2 (at least for me).

You can change the path to your copy of command.com as suits your needs. One
last note, you will still need a copy of command.com in the root in order to
format disks properly (no, I don't know why).

Also note that no environment variable can occupy more than 127 (128?) bytes
each!

Eric M. Boehm
EMB978@ALBNY1VX.BITNET
EMB978@LEAH.ALBANY.EDU