LNK2019: unresolved external symbol

[Dunken]

Hi

I'm new in C++. Can anybody explain why one of the following projects doesn't compile??

http://www.filedropper.com/cpptest

Thank you!!

[LB]

.cpp files aren't (shouldn't be) included ever, so they don't need include guards...
This line: TEST::MyStaticClass msc; where did this come from? There is no class in the TEST namespace called MyStaticClass.

[Dunken]

TEST:MyStaticClass comes from the other dll (CppTest). Out of this dll I included a header file...:

#include "../CppTest/MyStaticClass.h"

Now I thought I could use it...:

namespace TEST
{

//c'tor, d'tor

void MyUnitTest::Test()
{
	TEST::MyStaticClass msc;
	//do stuff
}

}

It seems like I didn't properly link CppTest... Obviously "include" itself is not sufficient. What else do I have to do?

[LB]

Including the header gives you the definition of the class, but all the functions only have declarations and are not defined. The cpp file has all the definitions - you'll have to figure out how you want to solve this problem (do not include the cpp file!)

[Dunken]

Thank you for helping me!!

Coming from C# I would do the following:

- add reference to CppTest
- add using TEST; on top of MyUnitTest.cs file (not even necessary)

Therefore I tried the following in C++:

- add reference to CppTest
- add #include "../CppTest/MyStaticClass.h" on top of MyUnitTest.cpp

Unfortunately this doesn't work...

As you can see CppTest itself compiles... I now just want to add some unit test. I created a new project and now I just want to use MyStaticClass which is defined in CppTest. Do I have to add CppTest to the linker-dependencies??

[LB]

If you want to make the class reusable, you should define its functions inline.

[Dunken]

?? Sorry, I think I get lost...

CppTest is an ordinary library... (it should be at least)
In CppUnitTest I want to test CppTest...

Where do I have to define functions inline? In CppTest??

[LB]

It's not a library or a DLL, you're including a header file as if it were part of your project. Here is an example of a class with inline functions:

class MyClass
{
  int value;
public:
  MyClass() : value(0) {}
  MyClass(const int &from) : value(from) {}
  MyClass(const MyClass &from) : value(from.value) {}

  void SetValue(const int& from)
  {//Notice that I implement the functions in the class definition
    value = from;
  }
  int GetValue()
  {
    return(value);
  }

  ~MyClass(){}
};

If you convert your MyStaticClass to a class with all inlined functions, it will be completely reusable without the need for a partner cpp file.

[Dunken]

I see...

Does this mean that I have to get rid of MyStaticClass.cpp and put all the stuff in MyStaticClass.h instead?

[LB]

If you want the class to be able to be used without needing a cpp file to go with it, yes.

[Dunken]

OK, I also found another solution which is probably basically the same:

#if defined(XYZLIBRARY_EXPORT) // inside DLL
#   define XYZAPI   __declspec(dllexport)
#else // outside DLL
#   define XYZAPI   __declspec(dllimport)
#endif  // XYZLIBRARY_EXPORT 

and then extend my class like:
class XYZAPI MyStaticClass

This allows me to keep my .cpp and .h files... (I don't know if that's an advantage though...)