Re: [avr-gcc-list] (no subject)

[Dave Hylands]

Hi,

Sending to list...

> I live a problem with avr gcc: When i use a global variable in the header
> file and simultaneously initialize it to nonzero value in the declaration,
> then the use of this header file in multiple project source files as an
> include causes "multiple definition error" on this specific lines in the
> header file. Not initialized globals (by myself) and defines do not cause
> any error.  the whole header file content  is in a conditional define, in a
> regular manner, so  i dont understand what is going on. what is wrong?

In the header file, you need to use the word extern.

Putting:

   int x;

says to allocate storage for an int sized variable named x. Since this
is in a header file, every C file that includes the header file will
try to create a variable named x, which is where the multiple
declarations are coming from.

Using:

   extern int x;

says that somebody else has allocated storage for an int sized variable named x.

--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/