Functions for arrays !!!!

Hi,
I´m trying of to make a function that receive two arguments :
- An array of int4
- A int4
The target of this function is to evaluate if the numeric argument is or
not into of the array !!!!!
/* If anybody know of some predefined function that has the same target,
tell me !!!*/

The code is following (tester.c)->

#include <pgsql/postgres.h>
#include <stdio.h>

bool tester(int4 o[],int4 a){
int i;
for(i=0;o[i]!=0;i++)
      if (o[i]==a)
                return('t');
return('f');
}

then I compile the code

gcc -c tester.c                               /*Thanks to */
gcc -shared -o tester.so tester.o    /*Michael J. Davis*/

, and get tester.so

I create the function in PostgreSQL ->

dbtest=>create function tester(_int4,int4) returns bool as
'$path/tester.so' language 'c';
CREATE

But when try to use it, ->

dbtest=>select tester('{1,2,3,4}',3);
ERROR:  stat failed on file tester.so
/*Here I hope a 't' */

I don´t know what´s happens !!!!!

Carlos Peralta Ramírez !!!!!