---
title: "OnTrailerUpdate | open.mp"
description: "This callback is called when a player sent a trailer update."
canonical: https://omp.itsneufox.com/docs/scripting/callbacks/OnTrailerUpdate
language: en
---

# OnTrailerUpdate

## Description

This callback is called when a player sent a trailer update.

| Name | Description |
| --- | --- |
| playerid | The ID of the player who sent a trailer update |
| vehicleid | The Trailer being updated |

## Returns

0 - Cancels any trailer updates from being sent to other players. Update is still sent to the updating player.

1 - Processes the trailer update as normal and synchronizes it between all players.

It is always called first in filterscripts.

## Examples

```c
public OnTrailerUpdate(playerid, vehicleid)
{
    DetachTrailerFromVehicle(GetPlayerVehicleID(playerid));
    return 0;
}
```

## Notes

warning

-   This callback is called very frequently per second per trailer. You should refrain from implementing intensive calculations or intensive file writing/reading operations in this callback.
-   This callback is not called for trains.

## Related Callbacks

The following callbacks might be useful, as they're related to this callback in one way or another.

-   [OnUnoccupiedVehicleUpdate](https://omp.itsneufox.com/docs/scripting/callbacks/OnUnoccupiedVehicleUpdate): This callback is called when a driver-less vehicle's position is synced by a client.

## Related Functions

The following functions might be useful, as they're related to this callback in one way or another.

-   [GetVehicleTrailer](https://omp.itsneufox.com/docs/scripting/functions/GetVehicleTrailer): Check what trailer a vehicle is pulling.
-   [IsTrailerAttachedToVehicle](https://omp.itsneufox.com/docs/scripting/functions/IsTrailerAttachedToVehicle): Check if a trailer is attached to a vehicle.
-   [AttachTrailerToVehicle](https://omp.itsneufox.com/docs/scripting/functions/AttachTrailerToVehicle): Attach a trailer to a vehicle.
-   [DetachTrailerFromVehicle](https://omp.itsneufox.com/docs/scripting/functions/DetachTrailerFromVehicle): Detach a trailer from a vehicle.