/*
 * call-seq:
 *    res.fmod( column_number )
 *
 * Returns the type modifier associated with column _column_number_. See 
 * the #ftype method for an example of how to use this.
 * 
 * Raises an ArgumentError if _column_number_ is out of range.
 */
static VALUE
pgresult_fmod(VALUE self, VALUE column_number)
{
        PGresult *result = get_pgresult(self);
        int fnumber = NUM2INT(column_number);
        int modifier;
        if (fnumber < 0 || fnumber >= PQnfields(result)) {
                rb_raise(rb_eArgError, "Column number is out of range: %d", 
                        fnumber);
        }
        modifier = PQfmod(result,fnumber);

        return INT2NUM(modifier);
}