How to compile external procedure for Linxu

Question

Hello to all.
I'm not able to find how to compile external procedure on Linux.
I have 64bit release Linux (I don't know if I need special 64bit library or not).
I found only something like that:
gcc -fPIC -shared -o comsh64.so comsh64.c
Listener are correctly configured.
Library is in Oracle bin directory.
If I run select externproc from dual ... I don't receive any error message but program don't work.
I think that there is some missing parameter in gcc or some small thing ?
Thank you for possible answeer
Filip

Answer 1

Do you have someone any idea?
Now I have 1 library, 2 functions and 1 package with 2 functions:
int renamefile(char source, char destination)
{ int result;
result=rename(source,destination);
return result;
int comexi (char *c)
{ int ret;
ret = system(c);
return ret;
FUNCTION callSystemI(c in varchar2) RETURN binary_integer is
EXTERNAL LIBRARY extern_utils
NAME "comexi"
LANGUAGE C
PARAMETERS (c string);
function renamefile (src IN varchar2, dst IN varchar2) return binary_integer
AS EXTERNAL
NAME "renamefile"
LIBRARY extern_utils
LANGUAGE C
PARAMETERS (src string, dst string);
The first function still don't works, second function works.
Why?