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Path: utzoo!linus!decvax!harpo!seismo!ut-sally!cyb-eng!shell!starr
From: starr@shell.UUCP (Bob Starr)
Newsgroups: net.micro.pc
Subject: Re: Does DOS function 48h work?
Message-ID: <156@shell.UUCP>
Date: Wed, 11-Jan-84 00:11:03 EST
Article-I.D.: shell.156
Posted: Wed Jan 11 00:11:03 1984
Date-Received: Fri, 6-Jan-84 02:25:22 EST
Organization: Shell Development CS Group, Houston, Texas
Lines: 17


printf("hello world")

When DOS invokes a program, all of available memory is assigned to
it (see p. E7, paragraph 2 in DOS 2.0 manual). You need to free
some memory before you can allocate it (using function 49h). But
what to set ES to when invoking function 49h is another story.

If your program does not terminate and stay resident, then just
figure out where the end of the program you are running is (after
the end of the data segment), add a few bytes (for safety), and
choose a segment around there to pass to function 49h. Or, for
that matter, since DOS has already assigned the space to you, just
use it!

If your routine terminates and stays resident, I know of no easy
way to determine where to begin freeing and allocating memory.