Uninitialized static variable in function

[Alexander Potashev]

Hi,

In the commit r51083
(http://git.reactos.org/?p=reactos.git;a=commitdiff;h=83ba2eecbf0ff43ec3a178…),
please, initialize "i" to 0. Non-initialized variable store garbage,
not zeroes.


-- 
Alexander Potashev

[Dmitry Gorbachev]

Hi,

>   please, initialize "i" to 0. Non-initialized
> variable store garbage,
>  not zeroes. 
It probably does not look very well, but otherwise correct:

>   If an object that has static storage duration is not
> initialized explicitly, then:
>  — if it has pointer type, it is initialized to a null pointer;
>  — if it has arithmetic type, it is initialized to (positive or unsigned) zero;
>  — if it is an aggregate, every member is initialized (recursively) according to these
> rules;
>  — if it is a union, the first named member is initialized (recursively) according to
> these rules.

[Javier Agustìn Fernàndez Arroyo]

teachers at college told us it is a *must* to initialize variables.....

On Sun, Mar 20, 2011 at 10:53 AM, Dmitry Gorbachev
<d.g.gorbachev(a)gmail.com>wrote;wrote:

>   Hi,
>
> >   please, initialize "i" to 0.
> > Non-initialized variable store garbage,
> >  not zeroes. 
>  It probably does not look very well, but otherwise correct:
>
> >   If an object that has static storage duration is
> > not initialized 
>  explicitly, then:
> >   — if it has pointer type, it is initialized to a
> > null pointer;
> >  — if it has arithmetic type, it is initialized to (positive or unsigned) 
>  zero;
> >   — if it is an aggregate, every member is
> > initialized (recursively) 
>  according to these rules;
> >   — if it is a union, the first named member is
> > initialized (recursively) 
>  according to these rules.
>
>  _______________________________________________
>  Ros-dev mailing list
>  Ros-dev(a)reactos.org
>  http://www.reactos.org/mailman/listinfo/ros-dev
>

[Ged Murphy]

You'll learn in due course that college lecturers are often wrong.


2011/3/20 Javier Agustìn Fernàndez Arroyo <elhoir(a)gmail.com>om>:
>   teachers at college told us it is a must to initialize
> variables.....
>
>  On Sun, Mar 20, 2011 at 10:53 AM, Dmitry Gorbachev <d.g.gorbachev(a)gmail.com>
>  wrote:
> >  
> >  Hi,
> >
> > >   please, initialize "i" to 0.
> > > Non-initialized variable store garbage,
> > >  not zeroes. 
> >  It probably does not look very well, but otherwise correct:
> >
> > >   If an object that has static storage duration is
> > > not initialized
> > >  explicitly, then:
> > >  — if it has pointer type, it is initialized to a null pointer;
> > >  — if it has arithmetic type, it is initialized to (positive or unsigned)
> > >  zero;
> > >  — if it is an aggregate, every member is initialized (recursively)
> > >  according to these rules;
> > >  — if it is a union, the first named member is initialized (recursively)
> > >  according to these rules. 
> >  _______________________________________________
> >  Ros-dev mailing list
> >  Ros-dev(a)reactos.org
> >  http://www.reactos.org/mailman/listinfo/ros-dev 
>  _______________________________________________
>  Ros-dev mailing list
>  Ros-dev(a)reactos.org
>  http://www.reactos.org/mailman/listinfo/ros-dev
>

[Javier Agustìn Fernàndez Arroyo]

O_O
why?

On Sun, Mar 20, 2011 at 11:21 AM, Ged Murphy <gedmurphy(a)gmail.com> wrote:

>   You'll learn in due course that college lecturers
> are often wrong.
>
>
>  2011/3/20 Javier Agustìn Fernàndez Arroyo <elhoir(a)gmail.com>om>:
> >   teachers at college told us it is a must to
> > initialize variables.....
> >
> >  On Sun, Mar 20, 2011 at 10:53 AM, Dmitry Gorbachev < 
> d.g.gorbachev(a)gmail.com&gt;
> >   wrote:
> > >
> > > Hi,
> > >
> > > > please, initialize "i" to 0. Non-initialized variable store garbage,
> > > > not zeroes.
> > >
> > > It probably does not look very well, but otherwise correct:
> > >
> > > > If an object that has static storage duration is not initialized
> > > > explicitly, then:
> > > > — if it has pointer type, it is initialized to a null pointer;
> > > > — if it has arithmetic type, it is initialized to (positive or 
>  unsigned)
> >  > > zero;
> > > > — if it is an aggregate, every member is initialized (recursively)
> > > > according to these rules;
> > > > — if it is a union, the first named member is initialized 
>  (recursively)
> > > >   according to these rules. 
> > >  _______________________________________________
> > >  Ros-dev mailing list
> > >  Ros-dev(a)reactos.org
> > >  http://www.reactos.org/mailman/listinfo/ros-dev 
> >  _______________________________________________
> >  Ros-dev mailing list
> >  Ros-dev(a)reactos.org
> >  http://www.reactos.org/mailman/listinfo/ros-dev
> >  
>  _______________________________________________
>  Ros-dev mailing list
>  Ros-dev(a)reactos.org
>  http://www.reactos.org/mailman/listinfo/ros-dev
>

[Adam]

I will suggest initialize them if you can. :)

On Sun, 20 Mar 2011 21:03:42 +1100, Javier Agustìn Fernàndez Arroyo  
<elhoir(a)gmail.com> wrote:

>   teachers at college told us it is a *must* to
> initialize variables.....
>
>  On Sun, Mar 20, 2011 at 10:53 AM, Dmitry Gorbachev
>  <d.g.gorbachev(a)gmail.com>wrote;wrote:
>
> > Hi,
> >
> > > please, initialize "i" to 0. Non-initialized variable store garbage,
> > > not zeroes.
> >
> > It probably does not look very well, but otherwise correct:
> >
> > > If an object that has static storage duration is not initialized
> > explicitly, then:
> > > — if it has pointer type, it is initialized to a null pointer;
> > > — if it has arithmetic type, it is initialized to (positive or  
> > unsigned)
> > zero;
> > > — if it is an aggregate, every member is initialized (recursively)
> > according to these rules;
> > > — if it is a union, the first named member is initialized  
> > (recursively)
> > according to these rules.
> >
> > _______________________________________________
> > Ros-dev mailing list
> > Ros-dev(a)reactos.org
> > http://www.reactos.org/mailman/listinfo/ros-dev
> > 

-- 
Using Opera's revolutionary email client: http://www.opera.com/mail/

[Alexander Potashev]

2011/3/20 Javier Agustìn Fernàndez Arroyo <elhoir(a)gmail.com>om>:
>   teachers at college told us it is a must to initialize
> variables..... 
When I was in high school, our teacher told me that a simple "int
a[5];" (without "= {0};") would initialize the array with zeroes. But
it didn't. At least, in old good Borland C/C++ 3.1.


-- 
Alexander Potashev

[Javier Agustìn Fernàndez Arroyo]

....so, depends on compiler

2011/3/20 Alexander Potashev <aspotashev(a)gmail.com>

>   2011/3/20 Javier Agustìn Fernàndez Arroyo
> <elhoir(a)gmail.com>om>:
> >   teachers at college told us it is a must to
> > initialize variables..... 
>  When I was in high school, our teacher told me that a simple "int
>  a[5];" (without "= {0};") would initialize the array with zeroes. But
>  it didn't. At least, in old good Borland C/C++ 3.1.
>
>
>  --
>  Alexander Potashev
>

[Dmitry Gorbachev]

> > >   teachers at college told us it is a must to initialize
> > > variables..... 
> >  When I was in high school, our teacher told me that a simple "int
> >  a[5];" (without "= {0};") would initialize the array with zeroes. But
> >  it didn't. At least, in old good Borland C/C++ 3.1. 
>  ....so, depends on compiler 
Global, and local static variables are initialized; local non-static
variables are not. I have no Borland compiler at hand, but I bet it
conforms to the standard!