Thread: Shared Variables Question.

Originally Posted by mintsmike

Hi, I am trying to make a program that uses lots of variables. I would like each variable to be accessible to every function used in the program, and also available to programs that use preprocessor directives to include it.

Sounds like a bad idea, i.e., overuse of global variables.

Perhaps you should state what is the real problem that you are trying to solve.

Originally Posted by mintsmike

Hi, I am trying to make a program that uses lots of variables. I would like each variable to be accessible to every function used in the program, and also available to programs that use preprocessor directives to include it.

Just a sample piece of code will do thanks,

Regards,
mintsmike

maybe you better consider the career of horror stories writer?

Job of the programmer is difficult without need to read such a terrible code

Don't do that! Using global variables is very bad programming style, because sooner or later (usually about the same point as you start having more than one source-file using the same variable) it gets troublesome to figure out which function(s) affect what variable(s).

Now, having said that, the way you do it, if you have a very good reason to share one or two global variables between different modules is this:

Code:

// globals.h

extern int myGlobalVar1;
extern double myGlobalVar2;

Code:

// somefile.c
#include "global.h"

...
code using myGlobalVar1 & 2
...

Code:

// main.c
#include "globals.h"

int myGlobalVar1 = 42;
double myGlobalVar2 = 3.1415926;

--
Mats

Originally Posted by mintsmike

I just want to know how to define a global variable?

With careful deliberation. Frankly, I am not convinced that the knowledge is safe in your hands, though it is quite easy, and also quite easy to find out by searching this forum and/or the Web.