Trying to make functions in 'C'

I'm tying to learn how to make function in 'C'.
I'm trying to compile a program I made in 'C'.
The command I gave were:

% gcc -fPIC -c addone.c -I/usr/local/pgsql/include
% ld -G -Bdynamic -o addone.so addone.o

and created the function in postgres like this:

CREATE FUNCTION add_one(int4) RETURNS int4
AS './addone.so' LANGUAGE 'c';

The function I made looks like this:

#include "postgres.h"

int
add_one(int arg)
{
return arg + 1;
}

But when I try to test the function in postgres I recieve this error:

ERROR: stat failed on file ./addone.so
ERROR: stat failed on file ./addone.so
Can anyone tell where did I make a mistake?
I have a linux on a PC.

Thank you.

Fabian.

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com