[Bug c++/47861] static variables inside member functions

["michal.t at tiscali dot it" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47861

--- Comment #7 from Michal Turlik <michal.t at tiscali dot it> 2011-02-24 09:44:53 UTC ---
Well guys it is probably silly but you need to consider a more specific 
case.



Base*
MyClass::next(bool reset)
{
  static Bases::iterator it 
= m_bases.begin();

  if(reset)
    it = m_bases.begin();

  Base* base 
= ((it != m_bases.end()) ? (*it++) : 0);

  return base;
}


void

MyClass::
init()
{
  Base* base = next(true);

  while(base) {


base->init();
    base = next(false);
  }
}


The default behaviour of 
init is to recall init on each child and each child will do the same if 
not specified differently.
The issue is clearly caused by having 
declared static the iterator.
Obviously the same snippet code can be 
replaced by a simple for each iterator construct.
As you have mentioned 
before - static means static...consider only the implication of a code 
written in this way...a 
forced definition of the iterator being static 
would probably prevent some unprapred c++ users to make similar 
mistakes.
Thank you all.


----Messaggio originale----
Da: gcc-
bugzilla@gcc.gnu.org
Data: 23/02/2011 22.28
A: <michal.t@tiscali.it>

Ogg: [Bug c++/47861] static variables inside member functions

http:
//gcc.gnu.org/bugzilla/show_bug.cgi?id=47861

--- Comment #6 from 
Jonathan Wakely <redi at gcc dot gnu.org> 2011-02-23 21:28:10 UTC ---

(In reply to comment #5)
> Also it is hard to produce a warning when it 
comes to a failure that will only
> be diagnostic at link time.

IIUC I 
think the OP wants a warning for:

struct S {
  int f();
};

int S::f() 
{
  static int i = 0;
  return ++i;
}

which doesn't require a 
definition and can't produce a linker error.  I think
adding a warning 
for this is silly.