Scope of fwd declaratoins of nested classes

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3 total messages Started by Gregory Bond Thu, 14 Dec 1995 04:52

#2923

Author: Gregory Bond
Date: Thu, 14 Dec 1995 04:52

26 lines
1525 bytes

Try this for a corner case:

class A {
  public:
	class B;
  private:
	class B {
	  public:
		int b;
	};
};

// Is A::B visible here? Or is the above declaration ill-formed?
// I.e. is the scope of A::B established when it is declared or when
// it is defined? or should the two scopes be the same?
// FWIW, g++ 2.7.1 thinks this is well-formed and A::B is visible.
	
--
Gregory Bond <gnb@bby.com.au> Burdett Buckeridge & Young Ltd Melbourne Australia
``Efforts to maintain the "purity" of a language only succeed in establishing an
  elite class of people who know the shibboleths.  Ordinary folks know better, 
  even if they don't know what "shibboleth" means.'' - Larry Wall

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Re: Scope of fwd declaratoins of nested classe

#2929

Author: Steve Clamage
Date: Thu, 14 Dec 1995 16:59

28 lines
1398 bytes

In article 95Dec14120500@dame.bby.com.au, gnb@bby.com.au (Gregory Bond) writes:
>
>class A {
>  public:
>	class B;
>  private:
>	class B {
>	  public:
>		int b;
>	};
>};
>
>// Is A::B visible here? Or is the above declaration ill-formed?

From the September draft, 11.1 "Access specifiers", paragraph 3:

"When a member is redeclared within its class definition, the access
specified at its redeclaration shall be the same as at its initial
declaration."

An example just like yours appears in the draft to illustrate the error.

---
Steve Clamage, stephen.clamage@eng.sun.com

[ comp.std.c++ is moderated.  Submission address: std-c++@ncar.ucar.edu.
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Re: Scope of fwd declaratoins of nested classe

#2962

Author: Ulf Schuenemann
Date: Thu, 21 Dec 1995 20:05

46 lines
1700 bytes


In article <4apjod$7tp@engnews1.eng.sun.com>, clamage@Eng.Sun.Com (Steve Clamage) writes:
|> In article 95Dec14120500@dame.bby.com.au, gnb@bby.com.au (Gregory Bond) writes:
|> >
|> >class A {
|> >  public:
|> >	class B;
|> >  private:
|> >	class B {
|> >	  public:
|> >		int b;
|> >	};
|> >};
|> 
|> An example just like yours appears in the draft to illustrate the error.

The only way I see to hide the definition of a public nested class
is to put it into a different translation unit.

// public header
class A {
    public:
	class B;
};

// implementation file for class A
class A::B {
    public:
	int b;
};


Ulf Schuenemann

--------------------------------------------------------------------
 ,_.   Ulf Schuenemann
#,  \  Fakultaet fuer Informatik, Technische Universitaet Muenchen, Germany.
 |   > email: schuenem@informatik.tu-muenchen.de
 v=-<  WWW:   http://hphalle2.informatik.tu-muenchen.de/~schuenem/


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