How to share one variable between 2 .c files?

Question

Consider a variable abulo. I am trying to share abulo between 2 .c files. Here is what I did --

1. Created a.h . This file contains the line, extern int abulo;
2. a.c contains a statement like this, int abulo = 0;
3. in b.c, a.h has been included. Then there is just a kprintf function printing the value of yours.

But when I try to run the code it shows me an output like this --

undefined reference to `abulo'

Tried to use the idea of the accpeted answer given here - How do I share variables between different .c files?

what am I doing wrong here ? How to get rid of this error ?

Answer 1

You should link a.o when building the executable. Example:

cc -c a.c
cc -c b.c
cc a.o b.o -o executable
#  ^^^ this is important