Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!ukc!edcastle!aiai!richard
From: richard@aiai.ed.ac.uk (Richard Tobin)
Newsgroups: comp.unix.questions
Subject: Re: sbrk(2) question
Message-ID: <4296@skye.ed.ac.uk>
Date: 11 Mar 91 13:44:04 GMT
References: <1991Mar8.180132.12025@Think.COM>
Reply-To: richard@aiai.UUCP (Richard Tobin)
Organization: AIAI, University of Edinburgh, Scotland
Lines: 16

In article <1991Mar8.180132.12025@Think.COM> barmar@think.com (Barry Margolin) writes:
>This question came up at work yesterday: when sbrk(2) is used to increase
>the size of the data segment, is the newly-allocated memory guaranteed to
>be empty?

There's one case where it amlost certainly won't be zero, which is when
memory has been previously alocated and released (eg by calling sbrk()
with a negative argument).  So it's unwise to rely on it even if the
operating system allocates zeroed (or zero-fill-when-referenced) pages.

-- Richard

-- 
Richard Tobin,                       JANET: R.Tobin@uk.ac.ed             
AI Applications Institute,           ARPA:  R.Tobin%uk.ac.ed@nsfnet-relay.ac.uk
Edinburgh University.                UUCP:  ...!ukc!ed.ac.uk!R.Tobin