Re: auto_ptr gcc version 3.3.1 (cygming special) problem

[Rolf Campbell]

#1)  This is not a cygwin issue, so it's off-topic here.
#2)  This is not even really a gcc issue, it's a C++ issue.
#3)  The problem is that you are trying to use static_cast too much.  It 
should only be used for built-in types (int, float, various pointers).

The older gcc seemed to allow incorrect use of static_cast, the new one 
requires you to use it right.

Just remove the static casts, and away we are:

int main(int argc, char *argv[])
{
  A a(1);
  auto_ptr<B> b = auto_ptr<B>(a.getB());
  A a2(2);
  auto_ptr<B> b2 = auto_ptr<B>(a2.getB());
  cin.get();
  return 0;
}
Or even:

int main(int argc, char *argv[])
{
  A a(1);
  auto_ptr<B> b(a.getB());
  A a2(2);
  auto_ptr<B> b2(a2.getB());
  cin.get();
  return 0;
}


Marcelo Rezende Módolo wrote:
Hi,
I am not shure that this is a error , but it is very strange...
//autoPtr.cpp
#include <iostream>
#include <memory>
using namespace std;
class B  {
public:
   B(int cid) : cid_(cid) { cout << "B(" << cid_ << ")\n"; }
   ~B() { cout << "~B(" << cid_ << ")\n"; }
private:
   int cid_;          };
class A  {
public:
   A(int cid) : cid_(cid) { cout << "A(" << cid_ << ")\n"; }
   ~A() { cout << "~A(" << cid_ << ")\n"; }     B* getB() { return new 
B(cid_); }
private:
   int cid_;  };

int main(int argc, char *argv[])
{
   A a(1);
   auto_ptr<B> b = static_cast< auto_ptr<B> >(a.getB());
   A a2(2);
   auto_ptr<B> b2 = static_cast< auto_ptr<B> >(a2.getB());
   cin.get();
 return 0;
}
If I compile this file with gcc version 3.2.3 (mingw special 20030504-1) 
no errors ocur (g++ -o autoPtr autoPtr.cpp).
But if I try to compile using gcc version 3.3.1 (cygming special), with 
the same command line (g++ -o autoPtr autoPtr.cpp),
this errors ocur:
autoPtr.cpp: In function `int main(int, char**)':
autoPtr.cpp:26: error: invalid static_cast from type `B*' to type `
  std::auto_ptr<B>'
autoPtr.cpp:29: error: invalid static_cast from type `B*' to type `
  std::auto_ptr<B>'

what is the problem??

thanks,
marcelo




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