#includes not working?

[ben657]

Hey, was wondering if you could shed any light on a recurring problem I keep getting. It's hard to explain, but sometimes the #includes I have at the top of a file seem to stop working. An example would be, say I have this code:

// ------------------------------------------
// CList.h

#ifndef CListH
#define CListH

class CList
{
public:
private:
};

#endif

// ------------------------------------------
// CEntity.h

#ifndef CEntityH
#define CEntityH

#include "CList.h"

class CEntity
{
public:
CList *List;
private:
};

#endif

// ------------------------------------------

Now this might compile fine, but later, after making a lot of changes or adding new parts, I might get an error like:

[C++ Error] CEntity.h({line number of CList appearance}): E2450 Undefined structure 'CList'

Sometimes I have managed to have a temporary workaround for the problem, like putting a prototype for the undefined class in the same file (even though it shoudln't be necessary). Then later on I can get away with deleting the prototype, because the #include starts to work again.
And the problem doesn't always happen with classes, it can be functions or just about anything.

So anyway, is there a common cause of this? The compiler I am using is the one included with Borland C++ Builder 6.

[Valmont]

You may have declared pure virtual methods but did not implement them. I can't tell. I really need to see the code.

[ben657]

Yeah, I know you'd probably be able to figure it out right away if I could give out my whole code Trouble is its kind of long, and I'd rather not release it yet anyway.

However, I'm sure I have not used any virtual functions or inheritance anywhere yet.

Is it possible the compiler is in fact having trouble with another part of the code, but doesn't report it yet.

[Valmont]

I don't know Borland.

However for Win32 I advice using Dev-Cpp:

See:
http://www.bloodshed.net/devcpp.html
At least these sort of problems are solved then. I never have them. For Linux, KDevelop is my thing.

[Valmont]

Besides, see if you can reproduce the problem with reduced code. If you succeed then you should post that. It's the way to do it anyway .

[ben657]

OK, I have got to a point where I can have an instance of a class in the .cpp file for a unit, but not in the header! For example this is fine:

// ------------------------------
// CEntity.h

#include "CList.h"

class CEntity
{
        void func ();
};

// ------------------------------
// CEntity.cpp

#include "CEntity.h"

void CEntity :: func ()
{
        CList *List;         
}

// ------------------------------

This gives an error:

// ------------------------------
// CEntity.h

#include "CList.h"

class CEntity
{
        void func ();
};

void CEntity :: func ()
{
        CList *List;         
}

// ------------------------------

The problem is that I have some members of the class that are CList type, so they have to go somewhere in the header.

[ben657]

Ah nvm I got it working. Just something small I commented out. I'll need to add it in again later but right now, I'm going to concentrate on making the program work properly. So I'll probably post back at a later time.