structure of a tcp driven qt interface

hello :)

i'm writing a little game: the engine is in nemerle, and the user interface is in qt in c++. the connection between the two is secured by a tcp connection.

i have, say:
- main.cpp
- mainWindow class defined in mainwindow.h and implemented in mainwindow.cpp
- canvasView class defined and implemented in canvasview.h

i need to have:
an instance of QSocket connected to the server

my question is:
where and how to define and implement the QSocket instance so that:
- i can use its socketSend method both from mainwindow.cpp and canvasview.h;
- its socketRead method can modify variables of the mainWindow instance defined in main.cpp, and the canvasView instance defined in mainWindow.cpp?

i've tried lots of ways and none worked :( could you help me, please?

> - canvasView class defined and implemented in canvasview.h
What's wrong with implemented in canvasview.cpp ?

> an instance of QSocket connected to the server
The existance of the object is declared in say main.cpp, and you pass references to it to whoever needs to know.

thanks, it helped :)

the thing is: i'm a newbie in c++ and must have been making some (probably, stupid) syntax mistakes, and thus never being able to compile the whole thing which finally led me to the conclusion that it is actually impossible.

anyway, now it all works and my headache of the last couple of days is eventually over; man, you cured my head and soul ;) thank you :)

ps. well, canvasview is pretty small and i thought it would be more comfortable to have it all in one file. is there something wrong about doing so?

> is there something wrong about doing so?
You'll find these problems later on
1. the file gets compiled into every source file you include it in. If you have member functions outside the class, then these will become multiply declared at link time. If they're all inline, you just end up with code bloat.
2. Any change to the implementation of canvasview will mean you have to recompile ALL the files which depend on it. The whole point of C++ is to separate the interface (.h) from the implementation (.cpp)

oh, yes, i haven't thought about it... actually, i've kept doing "qmake -project && qmake && make", and the whole thing not being too huge it compiles reasonably fast so i thought it easier than defining which files i want compiled every time i make a little change somewhere.
but of course, you are right :)

thank you very much for help :)