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Mail Archives: djgpp/1993/06/06/08:55:51

From: gal AT matis DOT ingr DOT com (Gal Shalif)
Subject: Re: static variable initialization
To: Tapio DOT Lehtonen AT cs DOT Helsinki DOT FI (Tapio Lehtonen)
Date: Sun, 6 Jun 1993 15:28:23 +0300 (EET DST)
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu, galfield!gal (Gal Shalif)
Organization: SEE Technologies Ltd.
Reply-To: gal AT matis DOT ingr DOT com

> 
> jih-shin ho: "static variable initialization" (Jun  5,  9:05):
> > Hi:
> >   I find that gcc won't initialize static variable if you don't initialize
> > it by hand.
> > 
> >   For example:
> > 
> >       static int i;  <-- The value of i is undefined.
> > 
> >       static int i = 0; <-- You must use '= 0' to initialize i.
> > 
> > 
> >   This behavior violates ANSI definition. 
> 
> Are You sure that ANSI C demands implicit initialisation to zero for any
> variables? I don't remember it that way, and could not find any mention
> about that in the book I had handy. Initialising to zero would
> be a bad idea anyway, since half of the time zero would not be a good
> initial value. 
> 
> >Is this a bug ?
> 
> I believe it is not a bug. Explicit initialisation is a must.  

    On page 219 of the C Programing Language - Second Edition (ANSI C) it is
    written:

        A static object not explicitly initialized is initialized as if it
    (or its members) were assigned the constant 0. The initial value of an
    automatic object not explicitly initialized is undefined.

> 
> 
> >   -- Jih-Shin Ho
> >
> 
> Department of Computer Science        Tapio Lehtonen       FAX 708 4441
> P.O. Box 26 (Teollisuuskatu 23)                     TELEX 122785 TSK SF
> SF-00014 UNIVERSITY OF HELSINKI       PHONE + 358 0 7084185   room D320
> FINLAND                               Tapio DOT Lehtonen AT Helsinki DOT FI
> 
> 
> 


-- 
-- Sincerely,

   Gal Shalif, R&D group

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|         Gal Shalif            | gal AT matis DOT ingr DOT COM (or ingr!matis!gal)  |
|         Software Engineer     | Voice: +972 9-584684, ext. 110          |
|         SEE Technologies Ltd. | Fax:   +972 9-543917                    |
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