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Frequently Asked Questions

Difference Between Server Commands and Client Commands

  • Server commands are commands registered by the server. They can be executed by the server itself as well as by other players connected to the same server.
  • Client commands are handled entirely by the client itself. They can only be executed by the client that registered them; other players and the server are unaware of the existence of client commands.

When LeviLamina runs on Bedrock Dedicated Server (hereinafter referred to as BDS), mods can only register server commands.
When Minecraft is in a local world, it is essentially running a BDS instance internally. In this case, mods can register both server commands and client commands.
When Minecraft is in multiplayer mode, mods can only register client commands.

You can obtain the server-side and client-side CommandRegistrar instances for command registration through:

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ll::command::CommandRegistrar::getInstance(false); // Server
ll::command::CommandRegistrar::getInstance(true);  // Client

Commands Registered in the Mod's enable() Method Work on the Server (BDS) but Fail on the Client

This happens because the timing of enabling all mods differs between the server (BDS) and the client.

  • The server enables all mods after server initialization is complete (when the world has already been loaded).
  • The client enables all mods after the game startup process is complete (when the main menu window appears).

Therefore, on the client side, registering commands in the enable() method will not succeed, regardless of whether they are client commands or server commands.

The solution is to listen for ServerCommandRegisterEvent and register server commands there, and listen for ClientCommandRegisterEvent and register client commands there.

ACCESS VIOLATION Exception When a Mod Calls MCAPI (e.g. Player::disconnect())

Please check whether the code calling MCAPI is running on the MC_SERVER thread. Most server-side MCAPIs can only be called from the MC_SERVER thread. This is a limitation imposed by Minecraft's game design.