Question

I have a set of code written in VS 6. I am trying to write a CLI wrapper for that in VS 2008. I included one of the VS6 header files in the CLI code and compiled.

While compiling I am getting

LNK2001: unresolved external symbol "public: virtual void __thiscall Someclass::SomeMethod(SomeObject& os).

When I searched for the method and the class in the error it correponds to the code,

Header File.

class SomeClass: public ParentClass
 {
  virtual void SomeMethod(SomeObject& os);
}

CPP File

void SomeClass::SomeMethod(SomeObject& os)
{
//Implementation here
}

SomeMethod is actually overridden from the ParentClass

When I make the declaration in the header file by adding a open and close curly braces as

virtual void SomeMethod(SomeObject& os) {};

the error disappears. But I cannot do that since it would result in one method having two bodies. Why is this behavior? How do I overcome this? Or Do I have to put any #pragma while including BS6 headers in CLI?

Answer 1

Sounds like you’ve not included ‘CPP File’ in your project. That would also explain why you don’t get an error when you have two bodies. To check this try putting a deliberate compile error in CPP File. If the compiler doesn’t complain that would prove that you aren’t compiling CPP File.