How can I retrieve a function result?

Hi pgsql community,

I'm using libpq C. I'm trying to execute a FUNCTION called "myFunction",

*********************************************************************************************************
PGResult *res;
res = PQexecParams ( conn, "select myFunction($1,$2,$3)" , 3, NULL,
paramValues, paraLenghts, paramFormats, resultFormat);

if ( PQresultStatus (res) != PGRES_TUPLES_OK)
{
//error
}else{
//ok
}

*********************************************************************************************************

It's works fine, however I dont know how can I retrieve the result that
return the FUNCTION "myFunction". "myFunction" is a postgres FUNCTION which
returns a INT.

Any advices??

thanks in advance.

Luis.

--
paz, amor y comprensión
(1967-1994)