FIX: Cannot Evaluate Structures in Classes

The information in this article applies to:

• The debugger included with: Microsoft Visual C++, 32-bit Edition, version 4.0

SYMPTOMS

The Visual C++ version 4.0 debugger cannot evaluate structures that are defined and declared inside a class when C7-compatible debugging information is generated.

In the Auto window you will get this error:

   CXX0030: Error: expression cannot be evaluated.

   CXX0017: Error: symbol "CMyClass::MyStruct" not found.

RESOLUTION

Use the /Zi compiler switch (Program Database) or make the structure definition global.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug was corrected in Visual C++ 4.1.

MORE INFORMATION

Sample Code to Reproduce Problem

/* Compile options needed: /Z7
*/
#include <string.h>

    int myInt;

    struct MyStruct
    {
        char string[30];
    };
    MyStruct myStruct;

    CMyClass()
    {
        myInt = 5;
        strcpy(myStruct.string, "Hello");
    }   // Set Break Point here
};


void main()

    CMyClass c;