Hello,

I have this files:

main.c
global.h
tc1_task/tc1_task1.c
tc1_task/tc1_task2.c
tc1_task/tc1_task3.c

well, in global.h file I have all my global varibales, and I would like to use in all my task.
But if I make include in all .c files I have the follow error:

main.c:23: multiple definition of `signum'
tc1_task/tc1_task1.c:23: multiple definition of `signum'
tc1_task/tc1_task2.c:23: multiple definition of `signum'
tc1_task/tc1_task4.c:23: multiple definition of `signum'

By other hand I put include file only in main.c file and the other files I declarate all my variables as extern. It works but not with all of them.
For example:

in global.h

typedef struct{
unsigned int contador;
}SHARED_DATA_typ;

SHARED_DATA_typ *shared_data;

And now I would like to use this struct in tc1_task/tc1_task1.c, and I put :

extern SHARED_DATA_typ *shared_data;

it does not work.

any advice????

Best regards

Yes - look at any real program out there, or even the GCC headers or kernel headers. They all use the same precompiler trick:

#ifndef FILE_NAME_H
#define FILE_NAME_H

... all declarations

#endif /* FILE_NAME_H */

Thanks a lot pinniped,

I have started to use linux two months ago, and it is very hard to understand.

best regards
John