[SOLVED] C++ : Project scope variable

[Klen]

I am building a project in Visual Studio 2008 in C++ where I have a couple of header and source code files. I would like to ask for your experience and knowledge regarding the possibility oif a project scope variable in C++. In other words, I would like the change a variable (lets say bool var) in A.cpp and have the changes reflect in B.cpp.
Thus if in A.cpp, var changes from 0 to 1, then in B.cpp the code reads var as 1 too.
Is it possible without setting up of events and interrupts?
(I could provide more details of what I am doing if needed. I havent done so, to keep the question simple)

Thank you for all the help in advance
Regards
Klen

 

[horace1]

yes, you define the variable in file A.cpp say and declare it extern in file B.cpp
conisder test.cpp which defines (allocates memory for variable) test

#include "test.h" 

bool test;			// define test

void changeTest(void)
{
	test =true;
}

and associated header file test.h which declares (says it is defined somewhere) test

extern bool test;			// declare variable test
void changeTest(void);		// prototype for function

and main program which uses a variable test defined in test.cpp

#include <iostream>
using namespace std;
#include "test.h"

int _tmain(int argc, _TCHAR* argv[])
{
	test = false;
	cout << test << endl;
	changeTest();
	cout << test << endl;;
	return 0;
}

when run prints

0
1

showing variable test changes from false 0 to true 1

 

[Klen]

That exactly answers my question. Sometimes one skips the most baisc things! I didn't even think about extern!
Thank you so very much.