accessing private filds in 3.3.x

accessing private filds in 3.3.x

[john gladkih]

Hi,

I found one stupid problem after migrating to gcc 3.3 - it does allow to
access private fields in classes. Please, look here:

#define RESOURCE( N, T, I, C )                           \
  class __##N : public noncopyable_t {                   \
    mutable T Value;                                     \
  public:                                                \
                                                         \
    T get() const { T t = Value; Value = I; return t; }; \
    void free() { if( Value != I ) { C; Value = I; } };  \
    T & operator() () const { return Value; };           \
                                                         \
    __##N  () : Value( I ) {};                           \
    ~__##N () { free(); };                               \
  } N

struct noncopyable_t { // it does not matter
  noncopyable_t() {}
  noncopyable_t( const noncopyable_t& );
};

class c_t {
private:
  RESOURCE( a_v, int*, 0, delete Value; );
};

int *foo() {
  return c_t().a_v();
}

a_v field is private in class c_t but it is accesible. why?!

[~]> /usr/local/gnu/bin/g++-3.3.2 -v
Reading specs from /usr/local/gnu/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/specs
Configured with: ./configure --prefix=/usr/local/gnu --program-suffix=-3.3.2 --enable-shared --enable-threads --with-cpu=i686 --enable-version-specific-runtime-libs --enable-languages=c,c++,java
Thread model: posix
gcc version 3.3.2

gcc 3.2.x did not have this problem.

-- 
john, http://john.kak-sam.to

Re: accessing private filds in 3.3.x

[Jim Wilson]

john gladkih wrote:
> I found one stupid problem after migrating to gcc 3.3 - it does allow to
> access private fields in classes. Please, look here:

I am not enough of a C++ expert to answer this.  However, I can suggest 
that you file a bug report into our bug database rather than send email 
to gcc-bugs.  Bugs filed into bugzilla get tracked, and it is more 
likely that you will get an answer.
-- 
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com

Re: accessing private filds in 3.3.x

[Jim Wilson]

john gladkih wrote:
> I found one stupid problem after migrating to gcc 3.3 - it does allow to
> access private fields in classes. Please, look here:

I forgot to do some trivial checking.  I reproduced the problem with 
3.3, but I got the expected result with 3.2 and pre-3.4.  Thus it 
appears that this problem has already been fixed in the development 
sources, and it will be fixed when gcc-3.4 comes out.
-- 
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com