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From: john@viper.UUCP
Newsgroups: comp.lang.c
Subject: Re: Query: Implementation with non-zero NULL
Message-ID: <1082@viper.Lynx.MN.ORG>
Date: Wed, 3-Jun-87 16:59:54 EDT
Article-I.D.: viper.1082
Posted: Wed Jun  3 16:59:54 1987
Date-Received: Sat, 6-Jun-87 04:32:46 EDT
References: <158@delftcc.UUCP> <1070@viper.Lynx.MN.ORG> <6873@mimsy.UUCP>
Reply-To: john@viper.UUCP (John Stanley)
Organization: DynaSoft Systems
Lines: 30
Keywords: C, NULL, portability

In article <6873@mimsy.UUCP> chris@mimsy.UUCP (Chris Torek) writes:
 >
 >Wrong.  See K&R, p. 198.  Similar (but no doubt more precise)
 >wording can be found in H&S and in the dpANS.  Unitialised static
 >pointers must contain NULL, or the implementation is broken [1].
 >Automatic variables, including registers, that are not initialised
 >contain trash; the trash may be machine dependent, as on, e.g.,
 >4BSD Vaxen, where new stack pages are zero filled.
 >

  The message I was replying to was discussing points relating to
common problems/pitfalls in writing portable code.  From this it
should be obvious that "what K&R says" is not as relevent as "what
have people encountered in real life".  With all due respect to
Chris and K&R, what I was (poorly) trying to say was, that when
trying to write portable code, you should never use a variable
before it's been explicitly initialized.  This may seem irrelevant
to you, but it may be significant to someone else trying to write
or port code to a system/compiler where the strict word-of-K&R
may not have been fully implemented.  

  What's that you say?  No program would ever fail to run on your
system because someone used a "feature" defined in K&R that didn't 
work that way on your system?  Mind telling me what you've been 
smoking and where I can get some?  :-)  :-)  :-)

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