Re: Destructor not called with forward declaration instead of include

On Apr 21, 7:43 pm, internetpet <internet...@[EMAIL PROTECTED]
> wrote:
> Say you have these files:
>
> BigClazz.h
>
>      class Clazz; // Note the forward declaration only , no include
> "Clazz.h"
>      class BigClazz
>      {
>          public:
>              BigClazz();
>              ~BigClazz();
>              Clazz* pclazz;
>      };
>
> BigClazz.cpp
>
>      #include "BigClazz.h"
>      BigClazz::BigClazz(){}
>      BigClazz::~BigClazz()
>      {
>          delete pclazz; // Here the destructor of of the Clazz object
> will not be called
>      }
>
> Clazz.h
>
>      class Clazz
>      {
>          public:
>              Clazz();
>              ~Clazz();
>      };
>
> Clazz.cpp
>
>      #include "Clazz.h"
>      Clazz::Clazz(){};
>      Clazz::~Clazz(){};
>
> main.cpp
>
>      int main(int argc, char *argv[])
>      {
>          BigClazz* pVM = new BigClazz();
>          pVM->pclazz = new Clazz();
>          delete pVM;
>      }
>
> If you run this you'll see that the Clazz destructor will not be
> called when BigClazz does "delete pclazz;" in it's own destructor. But
> if you replace the forward declaration in BigClazz (class Clazz;) with
> an include
> (#include "Clazz.h") then it works.

What I'm actually iffy on, is why you can compile code that deletes a
pointer to an incomplete type at all. This compiles with only a
warning about deleting a pointer to an incomplete type on VC9.

Can someone who is more of a language lawyer than I comment on if this
is permissible in the standard, and if so, why? It seems to me that
deleting an incomplete type would always be a mistake...

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