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Path: utzoo!mnetor!seismo!uwvax!umnd-cs!umn-cs!meccts!nis!viper!john
From: john@viper.Lynx.MN.ORG (John Stanley)
Newsgroups: comp.lang.c
Subject: Re: Query: Implementation with non-zero NULL
Message-ID: <1070@viper.Lynx.MN.ORG>
Date: Mon, 1-Jun-87 01:03:31 EDT
Article-I.D.: viper.1070
Posted: Mon Jun  1 01:03:31 1987
Date-Received: Tue, 2-Jun-87 06:18:17 EDT
References: <158@delftcc.UUCP>
Reply-To: john@viper.UUCP (John Stanley)
Organization: DynaSoft Systems
Lines: 35
Keywords: C, NULL, portability

In article <158@delftcc.UUCP> henry@delftcc.UUCP (Henry Rabinowitz) writes:
 >
 >Are static pointers initialized to all bits zero or to the null value
 >(as in ANSI spec)?
 >

  If, you're refering to an initialized static, it's whatever you
specify.  If, on the other hand, you're refering to an UN-initialized
static pointer, the answer is a resounding "Neither!"....  An un-
initialized variable is just that.  It can initialy hold literaly
-any- value that variable can possibly hold.  You should never assume
anything about any variable until you've set it.

  If, as you stated, you're writing a book on portability, you should
mention that neither of the alternatives you mention is guarenteed.
If the programmer wants anything, including null pointers -or- null
bits, in a pointer, the value -MUST- be explicitly defined.  I've
written code for more than one system where if you don't specify
the value, you get whatever was there before you.  

  The ANSI standard may specify something as a default, but if you
really expect to make your code portable you really need to explicitly 
tell the compiler what it's suppost to be doing.  That way you don't 
get as many unpleasant surprises when you try porting to another 
system...



  If, on the other hand, I've missed the point you were getting at..
"Oh really?  (long pause)  Nevermind...."

--- 
John Stanley (john@viper.UUCP)
Software Consultant - DynaSoft Systems
UUCP: ...{amdahl,ihnp4,rutgers}!{meccts,dayton}!viper!john