multiple declaration error

I have three files say

common_defs.h

main.c
#includes common_defs.h as well as common_defs.h
contains the main function

abc.c
#includes common_defs.h


i compile main.c and abs.c separately to creeate
the respective .o files
Now for the final compilation, my compiler (icc) gives multiple declaration error for all the constants defined in common_defs.h

Any solution,

Did you add inclusion guards to your header files...

Code:

---

#ifndef __CLASS_A_HPP
#define __CLASS_A_HPP

// Your class declaration

#endif

---

Yes I did

One more finding
I am using C. Also using constants are allowed as per the new C standard

The other thing i just found
is that if i use #defines instead of const int things work just fine

Is there any diff between the C and C++ constants that is causing problems.
I have also used extern "c"


Thanks

Well...you might want to take a look at the following FAQ...

Are you suggesting to use something like
extern const int x ?


To be very precise my problem is because I compile in stages
first main.o is created
then abc.o is created
both have space allocated for the common_defs

Now when i compile the object files together there is a multiple declaration error ?