Re: Inherited member( void )const - const to be or not to be

[Claudio Bley <bley at CS dot uni-magdeburg dot de>]

On Mon, Sep 06, 2004 at 12:40:10PM +0200, SVisor wrote:
> Hi,

Hi.

> If this is wrong list, please point me to a better one.
> 
> I have following code. If CONST (as described in code) is defined it 
> will not compile (unless I do a C cast to CProvider* in 
> CInherited::getProvider(void)const). *I* claim that it should compile 
> even if CONST is defined. As the "const" only tells the compiler that 
> the function will not change any members of the class, it says nothing 
> about the return value. GCC 3.4.1 20040625 wants to see "this" as 
> constant in the function.
> 
> What is your opinion?
> 
> Am I getting myself into trouble with the CInherited class if I use C 
> cast (with C++ static/dynamic_cast it fails to compile) to make it compile?

> 
> 	virtual CProvider* getProvider( void )CONST{ return this; }

This is forbidden. You can't assign a constant pointer (and "this" is const 
in the body of that function) to a non-const pointer:

  const int *pc;
  int *p;
 
  p = pc; 
  *p = 5;