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From: manis@ubc-cs.UUCP (Vince Manis)
Newsgroups: net.micro.pc
Subject: Re: set environment
Message-ID: <984@ubc-cs.UUCP>
Date: Mon, 18-Mar-85 15:58:36 EST
Article-I.D.: ubc-cs.984
Posted: Mon Mar 18 15:58:36 1985
Date-Received: Wed, 20-Mar-85 03:27:33 EST
References: <1200005@ur-univax.UUCP>
Reply-To: manis@ubc-cs.UUCP (Vince Manis)
Organization: UBC Department of Computer Science
Lines: 16
Summary: 

A pointer to the current environment variables is stored in the
segment prefix. I think that the offset is $5c, but I don't have
my DOS technical reference in front of me. The environment consists
of a sequence of strings, each terminated by a null byte ($00). The
last string is followed by a second null. 

Each string consists of a variable name, an equal sign, and a string.
There's no limitation other than a total environment limitation of 
32K. 

Thus to find the value of a given variable, simply search the environment
for a string beginning with the variable name followed by an equal sign.

A recent issue of PC Tech Journal had a package of Turbo Pascal routines
for doing DOS things. I didn't read the article carefully, but I believe
there was an example routine there.