exit_err(0 == file, world, err_open);
if ( write_uint32_bigendian(world->seed, file)
|| write_uint32_bigendian(world->turn, file)
+ || write_uint16_bigendian(world->score, file)
|| write_uint16_bigendian(world->player->pos.y + 1, file)
|| write_uint16_bigendian(world->player->pos.x + 1, file)
|| write_uint8(world->player->hitpoints, file)