Help me please !!!!

Primary, Sorry for my english !!!

Hi,

I ´m developing a several test database, for study. But I can´t create
any function, every time ERROR appears.
I write a C code in a plus2.c file

#include <pgsql/postgres.h>

int4 plus2(int4 a,int4 b)
{
return(a+b);
}

main() /* For getting *.out*/
{
}

, then I compile it (I made this of two ways)

cc -c plus2.c /* I get the object file *.o */

or

cc plus2.c plus2.out /*I get the *.out file */

When I create the function on postgresql, occurs this

db=> create function plus2(int4,int4) returns int4 as
'/var/lib/pgsql/plus2.o' language 'c';
CREATE

or

db=> create function plus2(int4,int4) returns int4 as
'/var/lib/pgsql/plus2.out' language 'c';
CREATE

Wherever, when I call the function plus2 from Sql sentence ...

db=> select plus2(6,6);
ERROR: Load of file /var/lib/pgsql/plus2.o failed:
(ô@(ô@/pgsql/plus2.o: ELF file's phentsize not the expected size

or, with plus2.out

db=> select plus2(6,6);
PQexec() -- Request was sent to backend, but backend closed the channel
before responding.
This probably means the backend terminated abnormally before or while
processing the request.

If anybody can help me, thank !!!

PD: I don´t disturb you, if I don´t need it really.