Path: utzoo!utgpu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!ists!yunexus!rreiner
From: rreiner@yunexus.YorkU.CA (Richard Reiner)
Newsgroups: comp.lang.c
Subject: sbrk() in MS C 5.1 on MS-DOS
Keywords: sbrk() msc msdos ms-dos
Message-ID: <15179@yunexus.YorkU.CA>
Date: 16 Sep 90 01:49:51 GMT
Organization: York U. Computing Services
Lines: 12

I'm trying to use sbrk(negative_number) to persuade MS C 5.1 to give
some of its heap back to MS-DOS in a small model program so as to
leave more room for a spawn().  My little program is only about 20K of
code + 2K of data, but it seems to grab and keep a full 64K data
segment, thus reserving about 85K for itself during the spawn().

sbrk(negative_number) gives me an error return if negative_number <
-400; and calling sbrk() even with a small argument causes the spawn()
call a few lines later to fail.

Have I missed something, or is this just the usual MS-DOS foolishness?

--richard