Launch parameters are variables passed to a game server at the time of start-up. These variables load before any other configuration variables and are separate from configuration variables and the server.json file. Launch parameters are best suited for loading information that the server needs access to immediately after starting.

You might want to use a launch parameter instead of a configuration variable in the following scenarios:

• Initialize a port number.

• Set the log directory.

However, it makes more sense to use configuration variables instead of launch parameters in most cases.

You must encase each launch parameter variable in dollar symbols ($$), two on each side. For example, a launch parameter named port converts to . The following code snippet has example launch parameters.

-port  -queryport  -log 

Server variables

Like build configuration variables, you can use the following server-specific variables in your launch parameters. The following table has example server variables, each with a type, description, and example value.

Default launch parameters

The following sections display the default launch parameters for games made with Unity and games made with Unreal.

Note: Build configuration variables are encased in double dollar symbols ($$).

Unity

The default launch parameters for games made with Unity include -nographics, -batchmode, and -logFile.

Tip: The recommended best practice is to use sessions to integrate Multiplay Hosting into your Unity game. Refer to Unity Editor command line arguments to learn more about the different flags you can use.

-nographics -batchmode -port  -logFile /Engine.log

Depending on the game, the launch parameters might also include the query port (queryPort) and query protocol (queryType).

-nographics -batchmode -port  -logFile /Engine.log -queryPort  -queryType 

Unreal

The default launch parameters for games made with Unreal include -log, and -port.

Tip: Refer to Unreal Engine command line arguments to learn more about the different flags you can use.

-log=$serverid.log -port=

Depending on the game and SDK you're using, the launch parameters might include the query port (queryPort) and query protocol (queryType).

-log=$serverid.log -port= -queryPort  -queryType