incomplete type error in singleton

Question

I need a pointer to my main class from a singleton class. The singleton class header is included in the main class.

In MainClass.cpp

mSingletonInstance->mMainClass = this;

To avoid a recursive inclusion problem I do not include my main class header in the singleton class, I just simply use a forward declaration of the main class.

In Singleton.h:

class MainClass;

class Singleton {
    public:
       MainClass *mMainClass;
};

The problem comes when I try to access a method from the main class... I get an incomplete type error.

In Singleton.cpp

Singleton::myMethod(){
    mMainClass->someMethod(); // incomplete type error
}

The MainClass and Singleton are already defined when this happens...

score 1 · Accepted Answer · answered Feb 22 '12 at 03:57

1

Seems like you didn't include mainclass.h in singleton.cpp.

answered Feb 22 '12 at 03:57

Dmitriy Kachko

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But you should do it. And after that find out what wrong with the other errors ))) – Dmitriy Kachko Feb 22 '12 at 04:02
Thanks, I used a forward declaration of Singleton class in MainClass.h, and then included Singleton.h in MainClass.cpp – Pier Feb 22 '12 at 04:07
redefinition of what? could you post a short version of your code somewhere? I'm sure that it is a matter of some typo or missing semicolon.. – Dmitriy Kachko Feb 22 '12 at 04:07
You'll need header guards: http://stackoverflow.com/questions/4767068/c-header-guards – Vaughn Cato Feb 22 '12 at 04:08

incomplete type error in singleton

1 Answers1