Re: static variable

From:

"Alexander Nickolov" <agnickolov@mvps.org>

Newsgroups:

microsoft.public.vc.language

Date:

Mon, 27 Aug 2007 11:50:10 -0700

Message-ID:

<uWAkPsN6HHA.4584@TK2MSFTNGP03.phx.gbl>

No offense meant, but do you actually stop to think before
you post? Do you even know what encapsulation means?

--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@mvps.org
MVP VC FAQ: http://vcfaq.mvps.org
=====================================

"George" <George@discussions.microsoft.com> wrote in message
news:47BD5AA3-A51B-497F-B27C-DCAB904E984A@microsoft.com...

Thanks Alexander,

Could you provide a sample about why returning the address of a function
local static variable breaks OO principle?

regards,
George

"Alexander Nickolov" wrote:

Well, it's a terrible practice because you introduce high coupling
between otherwise unrelated pieces of code. This breaks the
code encapsulation and thus goes counter to OO design principles.

--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@mvps.org
MVP VC FAQ: http://vcfaq.mvps.org
=====================================

"George" <George@discussions.microsoft.com> wrote in message
news:E011562A-3C56-4D6B-A0D6-A89518CF03EC@microsoft.com...

Thanks Jim,

Good answer! I have a further question about programming best practice.
Do
you think it is safe to let the address of the *local* static variable
as
the
return value of a function? Then other part of code (out of this
function)
will access or even modify the variable by the returned address of the
*local* static variable?

Any disadvantages of this approach?

Example,

int* func()
{
static int i;
// other code

return &i;
}

regards,
George

"Jim Langston" wrote:

"George" <George@discussions.microsoft.com> wrote in message
news:B26304FA-E4ED-48A9-89B9-B1DA6B8FA870@microsoft.com...

Hello everyone,

I am wondering how C or C++ manages static variable internally.
Since
each
time when we again a function again, if in this function, a static
variable
is defined, the value will be the value last time when we entered
this
function (i.e. will not be initialized again, and only initialized
at
the
1st
time).

I suspect it is stored in some global structure to reserve the
value?

The implementation can do it however it wants, as long as it does it.
I
would guess it stores the value in the same place it stores other
global
variables, but has someway to know what function/method/class it
belongs
to.
Maybe it mangles the name with the function name in front.
Foo@Variable
or
something.