Re: [patch] remove null-ifiers

["Yury V. Umanets" <umka-nJ1KrdHEGnBBDgjK7y7TUQ@public.gmane.org>]

On Tue, 2004-01-27 at 18:43, Matthew Wilcox wrote:
> On Tue, Jan 27, 2004 at 04:09:55PM +0100, Karol Kozimor wrote:
> > > -static uid_t asus_uid = 0;
> > > -static gid_t asus_gid = 0;
> > > +static uid_t asus_uid;
> > > +static gid_t asus_gid;
> > 
> > We certainly *don't* want to do that, last time I checked C did not
> > actually guarantee to zero out uninitialized variables -- unless it's
> > different in the kernelspace. Are you sure pointers are initialized as
> > NULLs?
> 
> Looks like you checked the wrong standard then.  Global variables are
> guaranteed to be zeroed, stack variables (ie function-local) have the
> behaviour you described.  Jes' patch is correct.

Global uninitialized variables should be located in BSS section of ELF. 

Then somebody should initialize BSS at the start of a program. In user
space this is done by crt.* small objects written in assembler and
built-in to each application by gcc.

In kernel space this should be done by kernel itself. And I guess, this
is done. So, I don't see any reasons to initialize global variables and
thus to make kernel data segment bigger...


-- 
umka



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