Global Variable across multiple files?

Guys,
yet another question.

How do I use global varibales across multiple files.

and where exactly do I define the "extern int count;" ?

lets suppose I have the following

myclass.h

myclass.cpp

mymain.cpp -> this is where the main() program exists.

basically I want my class to update a global variable everytime its called, and then I want to be able to read that variable from my main as well ?

any suggestions? I m trying the "extern" but getting some LINK error saying I have unsolved external symbols.

pls help
Thanks

Don't use a global variable for this. Add a static member to
your class instead.

in your header declare, for example:
extern int GLOBALINT;


in your .cpp declare, for example:
int GLOBALINT = 1;


If you want to use this global variable in other classes and etc, you have to include the header file which containes: extern int GLOBALINT;

Exactly. And the error 'unresolved external variable' that you were receiving was because you didn't define the variable anywhere. extern keyword doesn't define a variable i.e. doesn't allocate memory for it but gives compiler a hint that the variable is defined somewhere else and it's safe to use it down in the file.

Quote:

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Originally posted by souldog
Don't use a global variable for this. Add a static member to
your class instead.

---

You're right, static class member should be used. Is it me, or has there been an influx of "how do you use global variables" messages in the various C++ forums lately?

I'm asking this because usage of global variables should be discouraged. But unfortunately, it seems that others are reading very bad C++ books, reading C programming (not C++) books, or being taught by persons who really aren't good C++ programmers. I have a 100+ module library, and nowhere in there is a global variable that is shared between modules.

Regards,

Paul McKenzie

Global variables are a lazy programmers shortcut... As long as you don't define vast amounts of global variables you should be ok; it's not like a globally declared integer is going to cause harm

Mostly, agree with the words above.
But I don't like that kind of "dogmas" ("don't ever use or smth")... for each rule there can be exceptions