Article ID: 155292
Article Last Modified on 12/10/2003
APPLIES TO
- Microsoft Visual C++ 4.0 Standard Edition
- Microsoft Visual C++ 4.1 Subscription
- Microsoft Visual C++ 4.2 Enterprise Edition
- Microsoft Visual C++ 5.0 Enterprise Edition
- Microsoft Visual C++ 4.2 Professional Edition
- Microsoft Visual C++ 5.0 Professional Edition
This article was previously published under Q155292
SYMPTOMS
If new is defined as DEBUG_NEW and a call to new is made for a class that takes a reference to another class in the member initialization, then the destructor is not called for the referenced class for versions 4.0, 4.1, and 4.2.
This is illustrated in the output from the following example:
ClassA Constructor ClassB Constructor ClassB Destructor
The destructor for ClassA is not called.
NOTE: The Visual C++ 5.0 compiler generates the following error if you try to compile the sample code:
RESOLUTION
The best way to work around the problem is to move the new statement to be within the body of the constructor. For example,
ClassC() { mClassB = new ClassB("Goodbye"); }
STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been fixed in Visual Studio 97 Service Pack 3 and Visual C++ 6.0.
For more information, please see the following article in the Microsoft Knowledge Base:
170365 INFO: Visual Studio 97 Service Packs - What, Where, and Why
MORE INFORMATION
Sample Code
/* Compile options needed: /D_DEBUG */ #include <afx.h> #include <iostream.h> #ifdef _DEBUG #define new DEBUG_NEW #endif class ClassA { public: ClassA(const char *) { cout<< "ClassA Constructor" << endl; } ~ClassA() { cout<< "ClassA Destructor" << endl; } }; class ClassB { public: ClassB(const ClassA&){ cout << "ClassB Constructor" << endl;} ~ClassB() { cout << "ClassB Destructor" << endl;} }; class ClassC { public: ClassB *mClassB; ClassC() :mClassB(new ClassB("Goodbye") ) // Error { // mClassB = new ClassB("Goodbye"); // Workaround } ~ClassC() { delete mClassB; } }; void main() { ClassC TestClassInstance; }
Keywords: kbbug kbfix kbvs97sp3fix kbvc600fix kbcodegen kbcpponly kbcode kbcompiler KB155292