/* list_fields(table, field=nil) */
static VALUE list_fields(int argc, VALUE* argv, VALUE obj)
{
VALUE table, field;
MYSQL* m = GetHandler(obj);
MYSQL_RES* res;
rb_scan_args(argc, argv, "11", &table, &field);
res = mysql_list_fields(m, StringValuePtr(table), NILorSTRING(field));
if (res == NULL)
mysql_raise(m);
return mysqlres2obj(res);
}