/*
 * call-seq:
 *    res.ftype( column_number )
 *
 * Returns the data type associated with _column_number_.
 *
 * The integer returned is the internal +OID+ number (in PostgreSQL) of the type.
 */
static VALUE
pgresult_ftype(VALUE self, VALUE index)
{
        PGresult* result = get_pgresult(self);
        int i = NUM2INT(index);
        if (i < 0 || i >= PQnfields(result)) {
                rb_raise(rb_eArgError, "invalid field number %d", i);
        }
        return INT2NUM(PQftype(result, i));
}