console-command-system.md

Console Command System

To facilitate the writing of code that is used on both the client and server side the Half-Life Unified SDK has an abstraction for console commands to enable this without having to conditionally compile code with #ifdef CLIENT_DLL.

On the client side commands are prefixed with cl; on the server side commands are prefixed with sv. This is known as the library prefix.

The console command system uses the logger named cvar.

Registering commands

Registering a command is straightforward enough:

g_ConCommands.CreateCommand("command_name", [this](const auto& args) { MyMemberFunction(args); });

void CMyClass::MyMemberFunction(const CCommandArgs& args)
{
	if (args.Count() > 1)
	{
		Con_Printf("%s\n", args.Argument(1));
	}
}

Commands take a std::function object for a function signature void(const CCommandArgs& args). Typical use involves using a capturing lambda to forward command execution to a member function, as shown above.

You can also disable the use of a library prefix:

g_ConCommands.CreateCommand("command_name", [this](const auto& args) { MyMemberFunction(args); }, CommandLibraryPrefix::No);

Registering cvars

Registering a cvar is even simpler:

m_MyCvar = g_ConCommands.CreateCVar("my_cvar", "0", FCVAR_PROTECTED);

You can set the initial value and flags.

You can also disable the use of a library prefix:

m_MyCvar = g_ConCommands.CreateCVar("my_cvar", "0", FCVAR_PROTECTED, CommandLibraryPrefix::No);

Setting cvars on the command line

CVars registered with this system can be set from the command line in one of two ways.

Both ways require you to prefix the cvar name with :.

The first is to use the complete cvar name:

:sv_cvar_name argument

The second is to use only the base name without the library prefix:

:cvar_name argument

This allows you to set both the client and server version of a cvar at the same time.

CVar values should be quoted if they have spaces or if they start with a + or -.