Path: utzoo!telly!ddsw1!lll-winken!uunet!tut.cis.ohio-state.edu!PARIS.ICS.UCI.EDU!schmidt%crimee.ics.uci.edu
From: schmidt%crimee.ics.uci.edu@PARIS.ICS.UCI.EDU ("Douglas C. Schmidt")
Newsgroups: gnu.g++.bug
Subject: Re: g++ 1.32 is lax on protection
Message-ID: <8901270106.aa24874@PARIS.ICS.UCI.EDU>
Date: 27 Jan 89 09:05:34 GMT
References: <8901270021.aa08266@ICS.UCI.EDU>
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Lines: 63


 > I thought that was the point of `protected' vs. `private'.  If you change
 > to private you get the error.
 > 
 > 				beshers@carcvax.brc.uconn.edu

Hi,

I believe you're getting confused by the following (which is
admittedly weird at face value):

----------------------------------------
class foo {
protected:
   int i;
};

main () {
   foo bar;
   
   bar.i = 10; // error, protected members are not
               // visible to objects of the base
               // type.
}

g++ correctly says:

----------------------------------------
In function int main ():
test.c:11: member `i' is a protected member of class `foo'
----------------------------------------

However, the following *is* correct:

----------------------------------------
class foo {
protected:
   int i;
};

class bar : public foo {

public:   
   f () {
      i = 10; // OK, since bar is a derived type
   }
};
----------------------------------------

If you look at the example I showed (from Stroustrup's article, so it
had *better* be correct ;-)), you'll see that 

----------------------------------------
X a;
a.prot
----------------------------------------

is clearly trying to get ahold of the protected member, in the same
illegal sense of my first example above.  After all, ``a is not a Y!''

Does that make any more sense?

Doug