avoid destructor

I have this class:
---------------------------------------------
class A {
string a;
int instances;
A();
static vector<A> all;

public:
static A *CreateA(...... .............);

void operator delete(void *tex) {
A *t = (A*) tex;
if (t->instances) t->instances--;
}

static void GarbageCollecto r();
};
----------------------------------------------

CreateA checks if "string a" exists in any of vector's objects. If exists
increases counter and return Pointer else creates and adds in vector a new
object.
When I run "delete(objectA );" then C++ runs first destructor and after
"delete".
This means that "string a" destroyed.
How can I avoid this? Because in this pointer there are many objects and
"string a" destroyed for all. (avoid to run destructor, but run only
"delete")

Thanks

[Victor Bazarov]

<- Chameleon -> wrote:

I have this class:
---------------------------------------------
class A {
string a;
int instances;
A();
static vector<A> all;

public:
static A *CreateA(...... .............);

void operator delete(void *tex) {
A *t = (A*) tex;
if (t->instances) t->instances--;
}

static void GarbageCollecto r();
};
----------------------------------------------

CreateA checks if "string a" exists in any of vector's objects. If exists
increases counter and return Pointer else creates and adds in vector a new
object.
When I run "delete(objectA );" then C++ runs first destructor and after
"delete".
This means that "string a" destroyed.
How can I avoid this? Because in this pointer there are many objects and
"string a" destroyed for all. (avoid to run destructor, but run only
"delete")

Don't call it "delete", don't make it an operator, but instead
make it a function and call it "destroy". Define the operator
as private so nobody can invoke it without your knowledge.

Victor

[tom_usenet]

On Tue, 27 Jul 2004 22:34:16 +0300, "<- Chameleon ->"
<ch******@hotma il.NOSPAM.com> wrote:

I have this class:
---------------------------------------------
class A {
string a;
int instances;
A();
static vector<A> all;

public:
static A *CreateA(...... .............);

void operator delete(void *tex) {
A *t = (A*) tex;
if (t->instances) t->instances--;
By the time you get to operator delete the lifetime of the object has
ended, and accessing the instances member has undefined behaviour.
}

static void GarbageCollecto r();
};
----------------------------------------------

CreateA checks if "string a" exists in any of vector's objects. If exists
increases counter and return Pointer else creates and adds in vector a new
object.
When I run "delete(objectA );" then C++ runs first destructor and after
"delete".
This means that "string a" destroyed.
How can I avoid this? Because in this pointer there are many objects and
"string a" destroyed for all. (avoid to run destructor, but run only
"delete")

Don't call delete on pointers returned by CreateA, instead add a
DestroyA static member to A and have an unimplemented private operator
delete to ensure that no-one does call delete by mistake.

A better strategy would be to use a smart pointer. e.g.

#include <boost/shared_ptr.hpp>
#include <boost/weak_ptr.hpp>
using boost::shared_p tr;
using boost::weak_ptr ;

class A
{
string a;
static std::vector<wea k_ptr<A> > all;
public:
static shared_ptr<A> CreateA(..);
//...
};

See www.boost.org

Tom