invalid memory when using classes from a dll

this is the first time I've tried to export a class from a dll. what I've done is: - crated an interface (only pure virtual methods) - implemented this interface in the dll with a class that wont be exported - the class has a release method that calls delete on its this pointer - created开发者_JS百科 a Factory class with a static method that returns a pointer to the concrete class but as the interface. this class is exported. - the deletion of the returned object is done by calling its release method.

I tuck all this from this tutorial about classes in dlls.

The problem is that when I use this dll in another project everything goes ok until I call the release function on the object. Then it shows an assertion failed window with the message "_ASSERTE(_BLOCK_TYPE_IS_VALID(pHead->nBlockUse));"

Did this happened to anybody else? I know this is as simple as forgetting to use std:: when you start C++ , but as I said I just started this.

Thanks!

Is your factory function defined in the header? If it is, and the new for creating the object is in the header then calling delete from within the DLL can cause this error. The factory function needs to be exported by the DLL, only the declaration must appear in the header.

For instance, your header should look line this:

class MyInterface 
{
public:
  virtual void DoSomething() = 0;

  virtual ~MyInterface() {}
};

__declspec(dllexport) MyInterface * __stdcall MyInterfaceFactory();

The implementation of MyInterfaceFactory() must be contained within the DLL.

Thanks for your answers, and I'm sorry I started this for nothing!

The problem was very simple but hidden behind the interfaces , factory , and some other stuff. I was returning a pointer to an object that was declared as static because it has to be a singleton. Then I was trying to release this object. BANG heap corruption!!

My singleton object shouldn't have a release function in the first place; I'll solve this by extracting the release function in a separate interface , that will be implemented only by non static objects.